Brachydactyly a possible inherited anomaly at prehistoric Prince Rupert Harbour.код для вставкиСкачать
AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 76:363-376 (1988) Brachydactyly, a Possible Inherited Anomaly at Prehistoric Prince Rupert Harbour JEROME S . CYBULSKI Archaeological Survey of Canada, Canadian Museum of Ciuilization, National Museums of Canada, Ottawa, Ontario, Canada KIA OM8 KEY WORDS Paleopathology, Osteology, Brachymetapody, Inheritance, Northwest Coast Indians, British Columbia ABSTRACT Disproportionately short metacarpals or metatarsals in eight burial skeletons and three unusually short metapodials recovered as disturbed bones were identified in a 1500 B.C. to A.D. 500 skeletal series from eight archeological sites of the north mainland coast of British Columbia, Canada. At least ten people were affected from four sites for a minimum series frequency of 5.2%. Various factors clinically implicated in the occurrence of brachymetapody were investigated to account for the anomaly. Context-sensitive information suggested that trauma, infarction or infection, and individual or family-related malformation syndromes were unlikely possibilities. Some modern population data suggest that the series frequency was unusually high, particularly for fourth metatarsal involvement, the most commonly affected bone. Modern pedigree interpretations, ethnohistoric inferences,and the archeological contexts of the affected burial skeletons and site samples provide a framework for concluding that brachymetapody in the series was more likely due to the inheritance of an essentially isolated anomaly. Brachydactyly refers to short fingers or toes owing to anomalous development of one or more of the metacarpals, metatarsals, and phalanges. Widely acknowledged in modern clinical research, it is an individual malformation almost unknown in the literature of paleopathology or archeology. Abnormally short fourth metatarsals were reported for two adult female skeletons as part of the osteological surveys of an A. D. 1100-1200 American Indian site in the U.S. southwest and a late prehistoric period site in the Canadian plateau (Merbs and Vestergaard, 1985; Pokotylo et al., 1987). Details on the frequency of the anomaly and its possible interpretive significance were not discussed. This paper details the occurrence of brachydactyly and its somewhat more variable nature of expression in a 1500 B. C. to A. D. 500 skeletal series from eight shell-midden sites on the north mainland coast of British Columbia, Canada. Brachydactyly was principally identified by one, two, or three short metacarpals or metatarsals in eight burial skeletons and by three unusually short me- 0 1988 ALAN R. LISS, INC. tapodials recovered as disturbed bones. Four sites were represented, suggesting a fairly widespread distribution in this regional series. Among living subjects, disproportionately short metacarpals and/or metatarsals occur as sporadic individual anomalies (e.g., Beighton, 1978:200) or from acquired disorders (e.g., Poznanski et al., 1977:711) but have more commonly been reported as essentially isolated, autosomal dominant traits in families or as part of individual or familyrelated multiple malformation syndromes (e.g., Temtamy and McKusick, 1978: 187, 218-222,249-264). Problems in differential diagnosis have spawned a n often confusing literature with respect to specific digit involvement, possible genetic heterogeneity, nature and degree of syndrome involvement, and possibly associated skeletal malformations. Paleopathological diagnosis and interpretation are complicated by the fact that ~~ Received March 4, 1987; accepted November 3, 1987 364 J.S. CY BULSKI very few data are available on the general incidence of brachymetapody or its apparent variant expressions in human populations. In the absence of genealogical data, and lacking the potential for histological, biochemical, and other nonskeletal observations essential to differential diagnoses, the present study cannot resolve unanswered clinical questions concerning brachymetapody. The Prince Rupert Harbour materials also suffered from variable skeletal preservation and site disturbances, limiting the consistencywith which the anomaly and other skeletal malformations could be assessed in the affected individuals and in the sample as a whole. Some evidence, in the form of clinical reports, modern population data, the archaeological contexts of the examples, ethnohistoric inferences, other osteological data, and differential site concentrations, suggests that the apparently high frequency of brachymetapody at Prince Rupert Harbour may reflect a genetic characteristic of this sample without any syndrome relationship. MATERIALS AND METHODS Prince Rupert Harbour, about 65 km south of the Alaska-Canada boundary, is in the traditional territories of the Tsimshian, one of several major historic Northwest Coast Indian groups (Drucker, 1955). The skeletal series was recovered between 1966 and 1978 under the auspices of the National Museum of Man, Ottawa (recently renamed the Canadian Museum of Civilization), and studied as part of a multidisciplinary archeological investigation of the north coast of British Columbia (MacDonald and Inglis, 1981). Earlier osteological reports focused on cultural patterns of tooth wear and on culturally based postmortem bone modifications (Cybulski, 1974, 1978). Since those works were published, additional remains were excavated and studied resulting in a more comprehensive assessment of the total number of individuals and represented sites. Also, some revisions have been made in the ageat-death and sex identifications of individuals based on correlated morphological indicators in the series as a whole. These site data, incorporated in other recent treatments of the collection (Cybulski, 1986), are shown in Table 1. The excavated remains were largely represented as individual primary interments but not necessarily as complete skeletons. Many lacked various parts either through TABLE I . Summary of Prince Rupert Harbour individuals bv site and total series idants Site Dodge Island Garden Island Parizeau Point Boardwalk Lachane Baldwin Grassy Bay Ridley Island Total series Adolescents and adults and children' Males Females Sex? Total 7 5 6 15 9 3 1 1 47 8 13 2 66 31 16 - 3 139 5 10 - 4 - 35 20 3 1 4 1 - - - 1 78 6 20 29 12 120 61 22 1 5 270 'Fetal or newborn to 12 years. decay or extensive fragmentation, or as a result of prehistoric or recent site disturbances. Complete sets of hand and foot bones were rare, and some individuals lacked those parts entirely. Northwest Coast shell-middens are notorious for disturbed cultural and human remains, having been built up as refuse heaps in association with semipermanent (winter)villages or temporary (seasonal) camps over periods of hundreds or thousands of years (Fladmark, 1986). Portions of the mounds were dug and often redug for human interments and other cultural activities, and living quarters were sometimes built upon earlier segments of the middens. Natural erosion and modern development also took their toll at the Prince Rupert harbour sites (MacDonald, 1969; Inglis, 1974). Consequently, there were many disturbed and isolated bones that entered into the total count of individuals, effectively a minimum number estimate. Thirty-nine radiocarbon dates from skeletons, together with 60 other site dates and information on relative stratigraphic placements, indicated that all of the human burials were deposited between 1500 B.C. and A.D. 500 (Cybulski, in preparation; see also MacDonald and Inglis, 1981). In this context, the sites were contemporaneous and the deposition continuous, though there appeared to be less burial activity during the early third than in the later two-thirds of the 2,000-year range. About 16%of 225 datable remains could wholly or partly be relegated to the first third of the range, 44% to the second third, and 40% to the last third. Frequent overlap in the radiocarbon date ranges, however, suggested the cumulative mortuary program of a common regional population. BRACHYDACTYLY IN CANADIAN SKELETONS 365 Fig. 1. a: Short fourth and right fifkh metacarpals in burial 516. b: Short fourth metatarsals in burial 455; note also the unrelated impaction fracture in the distal end of the left f&h metatarsal. Owing to the variable preservation of skeletons and missing parts, it was not possible to assess all recovered individuals for brachydactyly and thereby obtain precise frequency data. The focus of observation, principally qualitative in scope, was on short metacarpals and metatarsals since those components were most readily identifiable numerically and by side. Although two examples are noted as part of this study, no attempt was made systematically to identify possibly shortened phalanges since many of those bones were missing and the side and numerical assignments of those present were often in doubt. RESULTS Table 2 details the affected individuals and bones by catalogue number (XVII-B series in the Ottawa museum), age-at-death, sex, and site affiliation. Illustrative examples are in Figure 1. Including the isolated bones, a t least ten people were affected. Two isolated elements, from two different sites, duplicated right and left fourth metatarsals in the affected burial 366 J.S. CYBULSKI TABLE 2. Individual and Harbour remains’ Catalogue Site Age Burial303 P 30-39 series Sex Side MC1 MC2 MC3 MC4 MC5 MT1 MT2 MT3 MT4 MT5 F Burial345 W 35-44 F Burial372 W 45-54 M W Burial397 L Burial455 22-28 25-34 M M Burial457 L 12-16 M? Burial505 B 45-54 M Burial516 B 16-20 F Isolated 353 W Adult ? ? Isolated 812 B Adult ? Isolated 853 B Adult Total bones affected Total series bones observed % affected ‘X short; o Boardwalk; L = = = distribution of short metacarpals and metatarsals in Prince Rupert R X L o R L R L R L R L R L R L R L R L R o o - o - - - o o - o o o o - - o o o o o o o o - - o o o o o o o o 0 0 x 0 - - - 0 0 - 0 0 o o - _ - - - - 0 0 - 0 - x o o o o - - x o o x o 0 - 0 0 0 x 0 o o o o o o o X x o o o 0 o o o o 0 - o o 0 o 0 o o o 0 0 o 0 _ 0 o o 0 o o o o o o o o 0 0 o X o o X 0 x 0 o o - X 0 - o o o 0 - 0 o x 0 - o o o o o o 0 0 X X X 2 184 1.1 0 245 0 0 239 0 2 216 0.9 1 197 0.5 3 225 1.3 0 245 0 normal; = bone missing or too incomplete for study. Site abbreviations:P Lachane; B = Baldwin. ~ skeletons. The isolated short first metacarpal, No. 812 in Table 2, might have been the missing left first metacarpal of burial 516 from the same site, though it probably was from a different person. The bone had been. collected from a different excavation unit, and it showed marked surface erosion in contrast to the better preserved metacarpals associated with burial 516. There was little disturbance of this burial on site, and its left first metacarpal may have been missed on recovery. About half the expected normal complement of hand phalanges and most phalanges of the feet were also missing in the laboratory. At the same time No. 812 could not be verified as a distinct brachydactylous individual relative to an isolated short fourth metatarsal recovered from the same site. The two bones may or may not originally have belonged to one person. Shortened hand and foot components in archeological remains are best noticed when entire hands or feet are available for study. In this way, the relative component lengths among digits can readily be compared qualitatively as they are in clinical radiographs. Occurrences in isolated bones may be difficult to identify unless population norms in length have been established. Each of the three isolated examples was distinctively short when observed qualitatively as well as when compared with the ranges and average = 0 230 0 8 245 3.3 0 214 0 Parizeau Point; W = lengths for complete series of presumed normal bones in the Prince Rupert Harbour sample. Where measurable lengths could be compared between normal and abnormal right and left counterparts in the same person, differences of 10 mm and 11 mm were noted for two sets of metatarsals, a difference of 13 mm was observed between the fifth metacarpals of burial 516, and a difference of 6 mm was recorded between the shortened right first metacarpal of burial 303 and the normal left bone. These differences were 16.5% to 29% greater than the proportionate differences between normal right and left counterparts in the Prince Rupert Harbour collection. The isolated first metacarpal, No. 812, was 1 mm shorter than the abnormal bone of burial 303 and 10 mm shorter than the normal right first metacarpal of burial 516. Table 2 also includes total numbers of first through fifth metacarpals and first through fifth metatarsals (sides combined) observed in the Prince Rupert Harbour series. Almost all counted were those in which the epiphyses were fully joined to the diaphyses. A few were those of 12-16-year-old individuals, the youngest age at which brachydactylous metapodials could feasibly be detected. The one affected individual in this group, burial 457, featured a shortened right fourth metatarsal in which the distal epiphysis ap- 367 BRACHYDACTYLY IN CANADIAN SKELETONS TABLE 3. Incidence of brmhydactyy among Prince Rupert Harbour individuals Site Dodge Island Garden Island Parizeau Point Boardwalk Lachane Baldwin Ridley Island Total series Individuals with metacarpals Freouencv % 0/9 0122 113 0176 0139 2/15 014 3168 0.0 0.0 33.3 0.0 0.0 13.3 0.0 1.8 Individuals with metatarsals Freouencv % 019 0118 015 4/83 2/34 2/15 014 U168 0.0 0.0 0.0 4.8 5.9 13.3 0.0 4.8 Individuals with metacarpals or metatarsals' Freauencv % 0110 0125 115 4/92 2/41 3/15 014 101192 0.0 0.0 20.0 4.3 4.9 20.0 0.0 5.2 'If nos. 812 and 854 in Table 2 represent separate individuals (see text), the incidence for Baldwin would be 4/16 or 25%, and the total series incidence would be 111193 or 5.7%. peared to have already fused but was extensively damaged postmortem. All other metacarpals and metatarsals of this person, indicated as normal in Table 2, had separate epiphyses. Each affected person lacked some of the phalanges. Those present appeared normal except in the case of burial 505. In this skeleton, in which the right first metatarsal was 11 mm shorter than the left, both first proximal foot phalanges appeared stunted compared with those of other individuals in the Prince Rupert Harbour collection. The series data in Table 2 indicate that metatarsals were more commonly affected than metacarpals and that the fourth metatarsal was most frequently shortened. Other affected bones included first, fourth, and fifth metacarpals, and first metatarsals. Since brachydactyly has largely been recorded clinically as an individual malformation, it is informative for comparative purposes to provide archeological frequency data in terms of affected individuals. This is clearly problematical when all individuals are not represented by all parts of the hands and feet. Table 3 reports three sets of data. The last column includes site and total sample frequencies based on all those individuals (12-16 years and older) who had at least one studiable metacarpal or metatarsal. A second includes only those individuals with normal or affected metacarpals, and a third only those persons with normal or affected metatarsals. None of these data are precise since not all bones could be studied in each subject. At best, each column provides a minimum frequency of occurrence. Additional information concerning the frequency of affected individuals is provided in the next section relative to specific digit involvement. DISCUSSION Individual occurrences of disproportionately short metacarpals and metatarsals have been reported as sporadic anomalies, i.e., apparently without family or syndrome significance (Beighton, 1978:200;Gates, 1946:407), as a result of metaphyseal infarction or infection (Greenfield, 1980:81-87), as a result of trauma (Greenfield, 1980:344),as skeletal anomalies in individual syndrome manifestations of gonadal dysgenesis (Finby and Archibald, 1963; Keats and Burns, 1964; Park, 19771, as part of several separately identified family-specific syndromes thought to represent genetic entities (Mollica et al., 1984; Stern et al., 1984; Temtamy and McKusick, 1978:259-2631, as part of several syndromes regarded as distinct genetic entities across family lines (Bell, 1958; Edeiken and Hodes, 1973:127, 176-180; Fitch, 1982; Poznanski et al., 1977; Steinbach and Young, 1966; Temtamy and McKusick, 1978:250-2591, and as inherited family traits with and without associated digital or other limb anomalies (Bell, 1951;Fitch, 1979;Holt, 1975;Ray, 1968; Ray and Haldane, 1965;Riccardi and Holmes, 1974; Temtamy and McKusick, 1978:187, 218-222). Family and medical histories, biochemical and histological tests, and examinations for other phenotypic abnormalities are essential for proper interpretation in clinical cases. In paleopathology, the issue is decidedly complex because only other skeletal changes, possible digital and sex distribution patterns, and inferences about the affected skeletons based on archeology and ethnohistory may be considered. Also, the clinical literature is often less than explicit concerning potentially augmentative data. The follow- 368 J.S. CYBULSKI ing four subsections argue for the elimination of other factors in the occurrence of brachymetapody at Prince Rupert Harbour in favor of its probable occurrence as an inherited isolated trait. Within this context, the following features of the sample appear pertinent: 1) multiple, including specific digit bilateral involvement in at least three people (four, if one includes burial 505 with its apparently short proximal big toe phalanges);2) the predominance of foot over hand involvement; 3) the consistency of fourth metatarsal involvement in six people; 4) a lack of other skeletal changes in the affected burials clearly indicative of a syndrome disorder related to brachymetapody; 5) an apparently high frequency of the anomaly; 6) archeological and ethnohistoric information suggesting a high probability that some of the excavated remains in the Prince Rupert Harbour series were those of close relatives; 7) a differential site distribution pattern in the occurrence of brachymetapody closely corresponding to that of another skeletal anomaly in the series believed to have familial significance.While more or less weight might be attached to each of these features separately, their conjunction points to the occurrence of an isolated inherited trait and diminishes the likelihood of other explanations. All digital injuries at Prince Rupert Harbour were in adult bones. Except for a possible greenstick fracture in a fibula of a 10-12-year-old, there was no gross evidence for limb trauma in growing children or adolescents. Unlike the pattern in brachymetapody, most digital injuries were in hands rather than feet, and single digit injuries were the rule. Eighteen metacarpals, nine hand phalanges, and six metatarsals were involved. Multiple component injuries were recorded in four of the 27 individuals, or 14.8% as opposed to multiple component occurrences of brachydactyly in 40% of that sample, and they were restricted to hands. One of the broken metatarsals was the left fifth of burial 455 who also featured bilaterally short fourth metatarsals. In view of a gross distortion evident in that bone, indicating a fracture &er growth was completed (see Fig. lb), and the bilateral nature of brachymetapody in this person, the association was likely spurious. The digital injury in burial 345 involved a fourth proximal hand phalange, clearly unrelated to that person’s short fourth metatarsal. Premature epiphyseal fusion apparently occurred in the short fourth metatarsal of burial 457, but this phenomenon has frequently been noted in nontraumatic expressions of brachymetapody (Steinbach and Young, 1966). On the likelihood of trauma Trauma might seriously have been entertained to explain occurrences of brachymetapody at Prince Rupert Harbour. Exclud ing equivocal examples, close to 40% of individuals exhibited traumatic fractures or hematomata, one of the more significant paleopathological characteristics of this series (Cybulski, 1986). Digital injuries of this nature were recorded in 27 individuals or, minimally, 14% of the total population (all those with at least one observable hand or foot bone), including two people with brachymetapody, Burials 345 and 455. Though trauma has been cited as a potential cause of brachymetapody clinically, the precise mechanism that results in an adult bone that is otherwise normal is unclear. Presumably, the damage would have to occur during growth and specifically involve the epiphyseal cartilage, apparently stimulating premature fusion of the epiphysis. On a series basis, the mechanism might expectedly be random, most often affecting no more than a single digit. On the likelihood of metaphyseal infarction or infection Brachymetapody resulting from metaphyseal infarction or infection has most commonly been linked with sickle-cell disease. This disease is almost exclusively found in Black African people and their New World descendants, and is not known to have been endemic among British Columbia Indians or, for that matter, other native North American populations. The disease often exhibits other skeletal changes (Edeiken and Hodes, 1973:360-374; Greenfield, 1980:74-94) that were not apparent in any of the Prince Rupert Harbour skeletons with brachymetapody. It has also been stated that the individual distribution of brachymetapody is not symmetrical in this disease and that there is no selective involvement of digits (Greenfield, 1980:85). On the likelihood of one or more syndrome relationships Disproportionately short metacarpals and/ or metatarsals have been implicated in at BRACHYDACTYLY IN CANADIAN SKELETONS least eight distinct and six family-specific multiple malformation syndromes.From both clinical and paleopathological perspectives, there are many problems involved in their identification and differentiation both within and outside the context of brachymetapody. It is beyond the scope of this paper to argue for or against the associations that have been made, to describe, explain and attempt to differentiate all of the features of the syndromes, and to detail their genetic or nongenetic bases. Those aspects have taken up a good deal of the clinical literature, often without firm conclusions and with confusing or contradictory results. Many problems stem from a lack of consistent reporting and detailed statistics concerning associated clinical abnormalities. Appendices A and B summarize those features that may be helpful to paleopathological diagnosis and interpretation. While the list of syndromes might suggest multiple possibilities of the occurrence of brachymetapody in any paleopathological series, certain considerations tend to diminish that likelihood. First, the degree of involvement of brachymetapody in each of the syndromes would appear quite variable (e.g., Appendix B), although knowledge of that involvement, particularly among the distinct entities, is also variable. Only Turner’s syndrome and Albright’s hereditary osteodystrophy have been studied in any statistical light with respect t o the occurrence of brachymetapody. These data, however, are wanting. The bulk of research involving Turner’s syndrome, a phenotypic disorder affecting females with one of the sex (X) chromosomesabsent or reduced, has focused on the detection in radiographs of a “positive or borderline metacarpal sign” as a possible diagnostic indicator of gonadal dysgenesis (Archibald et al., 1959). This focus has emphasized statistical knowledge of short fourth metacarpals almost to the exclusion of other hand or foot components occasionally noted or illustrated as short. Brachydactyly, in both hands and feet, has more explicitly been addressed statistically in Albright’s hereditary osteodystrophy, an “autosomal dominant with sex modification” (Fitch, 1982:15), and is regarded as a characteristic feature of the syndrome, the only one of the distinct entities so defined. A problem with the data is that at least two variant expressions of Albright’s hereditary osteodystrophy have been identified and one of 369 them, pseudo-pseudohypoparathyroidism, has often been reported largely on the basis of short metacarpals and metatarsals, a procedure that has led some investigators to conclude overdiagnosis of the syndrome in the literature (Fitch, 1982:17). The involvement of brachymetapody in Klinefelter’s syndrome, a sex chromosomal abnormality in males, and in male patients with myotonic dystrophy, an autosomal dominant disorder that may affect both sexes, in contentious. As with Turner’s syndrome, brachymetapody has been reported for those syndromes in terms of a positive or borderline metacarpal sign as a feature of gonadal dysgenesis (Keats and Burns, 1964). Others, however, have emphatically stated that the sign does not occur in Klinefelter’s syndrome (Archibald et al.,1959; Park, 1977). Outside of a summary statement by Keats and Burns (1964:312),no information could be found on the occurrence of short fourth metacarpals in myotonic dystrophy, a syndrome for which other skeletal changes have been reported in both sexes (see appendices). It is, therefore, uncertain to what extent the two syndromes might seriously be considered in the differential diagnosis of brachymetapody. There is uncertainty as well as to the degree of involvement of brachymetapody in the nevoid basal cell carcinoma syndrome, another autosomal dominant disorder, as indicated in the footnote to Appendix B. Similar problems exist for the LaurenceMoon-Biedl-Bardet syndrome, progressive myositis ossificans, and hereditary multiple exostosis, for which no comprehensive data are available on the involvement of brachymetapody. A second consideration with respect to the likelihood of multiple syndrome possibilities to explain the occurrence of brachymetapody concerns the family-specific entities (BSI, CHS, CRY, RUV, and TUO in Appendix A). The reported features of these “private” syndromes, both skeletal and nonskeletal, suggest many similarities to those that have been reported as distinct entities across family lines. The original authors of cryptodontic metacarpalia, published in 1971 (cited in Temtamy and McKusick, 1978:259), have since opined that their patients had Albright’s hereditary osteodystrophy (cited as a personal communication in Fitch, 1982). Similar reassessments may eventually prove to be the case with some or all of the other family-specific syndromes. 370 J.S. CYBULSKI One possible feature that might serve to eliminate most of the distinct entities from consideration in the Prince Rupert Harbour sample is the consistent emphasis on metacarpal involvement (see Appendix B). It is difficult to know, however, the extent to which this emphasis is a result of observational bias. Most clinically based research and reporting of brachydactyly in general have focused on hand rather than foot involvement, perhaps because hands are more readily visible or routinely x-rayed in potential subjects admitted to clinics or hospitals for treatment of their disorders. Other skeletal changes have variably been reported in all of the syndromes related to brachymetapody (Appendix A). Some of them are distinctive and far more important skeletal indicators (e.g., Appendix B), while others suffer from the same uncertainties of association or have been less commonly reported than brachymetapody. Only three changes, all from the second of these two classes, were present in any brachydactylous Prince Rupert Harbour skeletons: crowding of the dentition in burials 303,455,457, and 516; spina bifida occulta in burials 455 and 516; and hyperostosis frontalis interna in burial 345. While two changes were concurrent in individuals with brachymetapody, it is difficult to make much of the associations. Dental crowding has been implicated only in the family-specific Ruvalcaba syndrome and in direct association with a narrowed maxilla. It was not an unusual finding in the Prince Rupert Harbour series with, minimally, 17% of the population affected. Twenty-nine of 31 affected individuals, including three with brachydactyly, exhibited crowding only in the lower dentition. Spina bifida occulta has been implicated in three syndromes. The two skeletons with the anomaly lacked the more distinctive bone changes of the Laurence-Moon-Biedl-Bardet and nevoid basal cell carcinoma syndromes and burial 516, a female, lacked the more characteristic changes reported for Turner’s syndrome (Appendix B). Spina bifida occults, usually in the sacrum but also in cervical or lumbar vertebrae, was recorded in nine Prince Rupert Harbour individuals for a minimum series frequency of 5.2%. The anomaly has been regarded as a commonly occurring normal variant in modern populations (Bennett, 1972) and may, in fact, hold little significance for the identification of the syndromes related to brachymetapody (e.g., Greenfield, 1980:305-307, with reference t o Turner’s syndrome). Hyperostosis interna, an irregular overgrowth of bone on the inner table of the skull, most often in the frontal region, has been reported with Albright’s hereditary osteodystrophy and myotonic dystrophy. This feature, however, has been associated with many disorders unrelated to brachymetapody, and has been noted to be fairly common in healthy subjects, particularly middle-aged women (Capraro et al., 1970; Salmi et al., 1962; Verdy et al., 1980). The one in eight occurrence among the brachydactylous Prince Rupert Harbour individuals, a middle-aged female, is virtually identical with the 12.2% frequency reported by Salmi et al. (1962) for 982 normal subjects. Outside of the brachydactylous group, four individuals from Prince Rupert Harbour, including three females and one male, all estimated at 30 years of age or older, displayed hyperostosis frontalis interna or its more extensive form, hyperostosis calvariae diffusae. There were no indications of possibly associated abnormalities in these people. An overall series occurrence of 3.3%was recorded, considerably lower than the normal figure reported by Salmi et al. (1962). These differences were likely influenced by sex distribution differences between the samples. The sample of Salmi et al. had twice as many women as men, while the opposite was true for the Prince Rupert Harbour sample (see Table 1). Salmi et al. reported a 16.7%occurrence in women as opposed to only a 2.7%occurrence in men. On the likelihood of an inherited anomaly Some modern population data suggest that the frequency of brachymetapody at Prince Rupert Harbour was unusually high, one element that would argue for its occurrence as an inherited rather than sporadic anomaly. These data pertain exclusively to the fourth metatarsal, the most commonly affected bone. Tanaka (1963) reported three cases in a sample of 3,115 Japanese schoolgirls and “no case . . . among boys in a sample of similar size.” For samples of several thousands of individuals from different parts of India, Ray (1968) recorded frequencies of 0.13%to 0.66%.At Prince Rupert Harbour, right bones were affected in each of the six cases, two of which also had short left bones. There were 128 right and 117 left fourth metatarsals in the total series. These data indicate that 4.7%of people were affected, a figure far in excess of what might be expected on the basis of the Japanese and East Indian data. BRACHYDACTYLY IN CANADIAN SKELETONS For his samples, Ray (1968)concluded that the manifestation of short fourth toes behaved as an irregular autosomal dominant with penetrance values between 23% and 40%, decreasing with increased distance from the propositi (see also Ray and Haldane, 1965). Thirty-eight of 61 examined pedigrees had two or more affected individuals. Both bilateral and unilateral expressions were noted (130 and 76 cases respectiveIy). Eight percent of the affected had other limb anomalies, occasionally also present in unaffectedfamily members. They included short big toes or third toes, short thumbs or fourth fingers, short distal phalanges, elongated index fingers or second toes, polydactyly or syndactyly, club foot, or absence or reduction of the patella. Ray suspected that most of these anomalies were manifestations of a main gene affecting short fourth metatarsals, possibly under the influence of modifying genes. Other studies concerning the inheritance of brachymetapody have centered on separate pedigree occurrences. Families have been reported in which only the fourth metatarsal, only the fourth metacarpal, or both elements are short; only the second metacarpal is short; only the first metatarsal is short; short fourth or fifth metacarpals predominate but other finger o r toe digits are affected; multiple digits are involved together with other skeletal anomalies like those reported by Ray; or there is multiple or single digit involvement with short stature (e.g., Bell, 1951; Fitch, 1979). Authorities generally agree that autosomal dominance and reduced penetrance are in operation, but cannot decide whether one or more genes are involved. All forms of brachymetapody were initially given the classification of type E brachydactyly to distinguish them from other types mainly involving the phalanges, and genetic heterogeneity was proposed (Bell, 1951). Fitch (1979) has suggested that the phrase “type E” be reserved for multiple digit involvement together with short middle and/ or distal phalanges and short stature, and that forms in which short fourth metatarsals and/or metacarpals occur alone or predominate might eventually prove to represent an inclusive separate genetic entity. Although additional large-scale population studies are obviously needed, Ray’s (1968) results and Fitch’s (1979) offering suggest a pattern for genetic interpretation of the Prince Rupert Harbour data in which short fourth metatarsals predominate but other metatarsals or metacarpals may also 371 be short. Those individuals with short metacarpals need not have been part of a different genetic complex. In an English pedigree, for example, Holt (1975) illustrated a woman with short fifth metacarpals whose son and granddaughter each exhibited short left fourth metatarsals. Without genealogical information, consanguinity cannot be proven among any of the Prince Rupert Harbour individuals with brachymetapody. However, archaeological data and ethnohistoric inferences suggest a high probability that some of the excavated remains have been those of close relatives. In their regional overview of the excavation project, MacDonald and Inglis (1981) identified the four sites with brachydactylous individuals as continuously occupied winter villages and a fifth, Grassy Bay, as a seasonal camp. Although 1300 years separated the burial population from the historic period, the sites as a whole were referred to the Coast Tsimshian, or Tsimshian proper, one of three dialect-based Tsimshian subgroups. Historically for the Tsimshian area (Boas, 1916; Garfield, 1939), winter villages served as the focus of family life and tribal activities, and seasonal camps provided temporary quarters for individual activities directed to fishing and plant gathering, and the preparation of winter food resources. In Tsimshian society, tribes were political units formed of one large or several closely situated smaller villages, while families were the significant functioning social units. The villages were variably sized clusters of dwellings, each house holding 20-40 persons, most of whom were members of a single lineage including four or more generations. Where houses were not large enough to hold the entire lineage, all members usually lived in the same village. However, families, with their distinctive names, crests, and other ownership privileges, often cross-cut the village communities of a tribe. Village cemeteries were designated on land contiguous with the villages or nearby on small offshore islands. No details are available as to whether family members were buried close together, but other northern Northwest Coast groups with simiIar family-based social systems are known to have commonly practiced lineage burial so that “members . . . were kept close together as they were in the communal house during their lifetime” (MacDonald, 1973:l). Although the extension of this information 1300 years into the past is inferential, it 372 J.S. CYBULSKI suggests the possibility of consanguineous relationships among at least some of the remains within the Prince Rupert Harbour village sites and, potentially, between sites. Currently, the archaeological analysis is not susciently complete to conclude possible tribal entities among the village sites which might serve as a basis for grouping them into larger comparative population units. However, it is of interest that the three largest village site samples each had at least two individuals with brachydactyly. Of the three, the Baldwin site, with at least three and, possibly, four affected people and the highest concentration, also exhibited the highest concentration at any site of another, likely independent, skeletal anomaly believed to have familial significance. The frequency of posterior atlas bridging was 36.4% (n = 111, comparable to that shown for first-degree relatives in modern Canadian and United States White communities (Saunders and Popovich, 1978). The total Prince Rupert Harbour series frequency was 15.3% (n = 1181, lower than the general population figures for those communities (ibid.). The frequencies a t the larger Lachane and Boardwalk sites were 11% (n = 27) and 17.5%(n = 571, corresponding to their lower incidence of brachymetapody, both, perhaps, a reflection of their broader population genetic (i.e., familial) spectra. Area distributions of the recovered burials at each of these sites are also pertinent to this discussion. The maximum linear distance over which the Baldwin site burials were distributed was 30 m, while the burials of the Boardwalk and Lachane sites were distributed over distances of 88 m and 107 m, respectively. Burials 505 and 516 at the Baldwin site were recovered about 15 m apart and were archaeologically contemporaneous, dating in the late third of the Prince Rupert harbour burial sequence. Approximately the same distance maximally separated the three brachydactylous burial skeletons of the Boardwalk site; two were assigned to the middle part of the burial sequence and the third bridged the middle to late parts. Of stronger inferential value for a lineage relationship was that the only two individuals with brachymetapody a t the Lachane site were recovered from the same 1.5m2 excavation unit and within the same excavation level. They bridged the middle to late thirds of the burial sequence. None of the information in this section is conclusive of an inheritance factor to explain the occurrence of brachymetapody at Prince Rupert Harbour. However, it does provide a much more context-sensitive framework for interpretation than other explanations for short metacarpals and/or metatarsals cited in the clinical literature. Clearly, it would be useful to have more general, regional, and site-oriented population studies on the frequency of brachymetapody and its variant expressions, particularly in terms of its occurrence in modern and other prehistoric North American Indian samples. ACKNOWLEDGMENTS Support for this study was provided by the Canadian Museum of Civilization, Ottawa. I thank George F. MacDonald and Richard I. Inglis for entrusting me with the analysis of the Prince Rupert Harbour skeletal remains and for providing free access to their site excavation records. Christine Midwinter and Nancy Struthers, with the museum library services, aided greatly with bibliographic searches and interlibrary loans, and the Ottawa University Health Sciences Library provided generous access to their collections. Shelley Saunders, Robert McGhee, and Patricia Sutherland kindly commented upon earlier drafts of this paper, providing valuable advice in their fields of expertise. LITERATURE CITED Anderson, DE, Taylor, WB, Falls, HF,and Davidson, RT (1967) The nevoid basal cell carcinoma syndrome. Am. J. Hum. Genet. 19:12-22. Archibald, RM, Finby, N, and De Vito, F (1959) Endocrine significance of short metacarpals. J. Clin. Endocrinol. Metab. 19:1312-1322. Beighton, P (1978) Inherited Disorders of the Skeleton. New York Churchill Livingstone. Bell, J (1951) On brachydactyly and symphalangism. Treasury Hum. Inheritance 5 (part 1):l-31. Bell, J (1958) The Laurence-Moon syndrome. Treasury Hum. Inheritance 5 (Part 3):51-96. 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General Short stature or dwarfism Tall stature Acromegalic features Osteoporosis Osteosclerosis Subperiosteal erosions Single or multiple exostosis SoR-tissue calcification or ossification Skull Hydrocephaly or megalocephaly Microceuhalv Oxycepialy " Marked brachycephaly Marked dolichocephaly Marked frontal bossing Marked parietal bossing Undeveloped frontal sinuses Enlarged frontal sinuses Thickened cranial vault bones Hyperostosis interna Bridged clinoid processes Hypertelorism Facial asymmetry Destructive jaw cysts Narrow or hypoplastic upper jaw Highly arched palate Small mandible Dentition Congenital edentia Loose or edopic teeth Defective dentin or enamel Impacted teeth Crowded teeth Supernumerary or congenitally missing teeth, or teeth selectively reduced or increased in size Sternum and ribs Thick or abnormally segmented sternum Bifid or fused ribs Thinned and narrow ribs Skeletal change X X X X X X X X X X X X X X X X X X X x x X X X X X X X X X X X X X X X x X X x X x X X x X x X x X X X x X X X x AH0 BSI CHS CRY EAB HME KLI LMB MY0 NBC PMO RUV l W 0 TUR Syndromes' APPENDIX A. Additional skeletal changes reported in syndromes related to short metacarpals andlor metatarsals X X X X X X X X X x X X x x X X x X X x x x X X X X X X X X x X X X x X X X X X X X X X X X X X ‘AH0 = Albright’s hereditary osteodystrophy (pseudohypoparathyroidism and pseudo-pseudohypoparathyroidism) (Fitch, 1982; Halal et al., 1985; Steinbach and Young, 1966); BSI = Biemond’s Syndrome I (Bell, 1951:26; Temtamy and McKusick, 1978:259); CHS = corneal changes, hyperkeratosis, short stature, brachydactyly and premature birth (Stern et al., 1984); CRY = cryptodontic rnetacarpalia (Fitch, 1982; Temtamy and McKusick, 1978:259); EAB = exostosis, anetodemia and brachydactyly (Mollica et al., 1984);HME = hereditary multiple exostosis (Edeiken and Hodes, 1973:229-231; Fitch, 1982; J d e , 1958:150-168; Steinbach and Young, 1966);KLI = Klinefelter’s syndrome (Edeiken and Hodes, 1973:316-317; Keats and Bums, 1964); LMB = Laurence-MoonBid-Bardet syndrome (Bell, 1958; Edeiken and Hodes, 1973:127; Levy et al., 1970); MY0 = myotonic dystrophy (Caughey, 1952; Ishewood and Mawdsley, 1963; Keats and Bums, 1964); NBC = nevoid basal cell carcinoma syndrome (Anderson et al., 1967; Gorlin et al., 1965); PMO = progressive myositis ossiiicans (Edeiken and Hodes, 1973:176-183); RUV = Ruvalcaba syndrome (Temtamy and McKusick, 1978:259); TUO = Tuomaala syndrome (Temtamy and McKusick, 1978:262-263); Turner’s syndrome (Edeiken and Hodes, 1973:307-315; Finby and Archibald, 1963; Lemli and Smith, 1963). Spine Scoliosis Kyphosis Osteochondritis of body plates Fusion of select vertebrae Progressive fusion of vertebral centra Squared lumbar bodies Hemivertebrae Maldeveloped atlas or axis Spina biflda occulta Limbs Short limbs Abnormal clavicle form Bowed forearm long-bones Proximal radio-ulnar synostosis Shortened ulna relative to radius Elongated distal ulna Medially sloping distal radius surface Fusion of select carpal bones Pseudo-epiphysis in second metacarpals Male pelvic features in women Femur neck thickened with irregular bony overgrowths Depressed medial tibia plateau with enlarged femoral condyle and proximal tibia laterally bowed Polydactyly in hands andor feet Fused middle and distal foot phalanges J.S. CYBULSKI 376 APPENDIX B. Most l&ly occurring skeletal changes, sex distributwns, and features of brachydactyly in distinct syndromes related to short metacarpals andlor metatarsals Syndrome Albright’s hereditary osteodystrophy Hereditary multiple exostosis Klinefelter‘s syndrome Laurence-Moon-Bid-Bardet syndrome Myotonic dystrophy Nevoid basal cell carcinoma syndrome Progressive myositis ossificans Turner’s syndrome Comments‘ Short stature and brachydactyly; females affected twice as often as males; brachymetapody in 59% to 96% of patients with multiple digit involvement common, and short distal hand phalanges in 71% to 78% of patients Widely distributed exostoses or osteochondromata in juxta-epiphyseal regions of long-bones, bowed forearm bones and short limbs; males account for 70% of cases; short metacarpals “common” Skeletal changes inconsistent; incidence approximately 1 in 800 live male births; short fourth metacarpal (‘‘positive or borderline metacarpal sign”) inconsistent Short stature and polydactyly; males and females about equally affected; short metacarpals, metatarsals or phalanges occasionally reported Thickened cranial vault bones and hyperostosis frontalis interna; males and females about equally affected; short fourth metacarpal (“positive or borderline metacarpal sign”) in approximately half of male patients with testicular atrophy Multiple destructive jaw cysts and bifid or fused ribs; males and females about equally affected short fourth metacarpal in less than 4% of patients Ossification of muscles, tendons, and fascia, and microdactyly of big toe; predominant in males; short first and fdth metacarpals occasionally reported Short stature, early onset osteoporosis, and knee deformity; incidence estimated at one in 3,000 live female births; short fourth metacarpal (“positive or borderline metacarpal sign”)in 33%to 70% of patients, though other metacarpals, metatarsals or hand Dhdanees occasionallv noted as short ‘References in Appendix A also Poznanski et al. (1977) for Albright’s hereditary osteodystrophy, Kosowicz (1965) and Park (1977) for Turner’s syndrome, and Thompson and Thompson (1973:167, 170) for incidence data on Turner’s and Klinefelter’ssyndromes. The incidence of brachymetapody in the nevoid basal cell carcinoma syndrome was calculated from data for 55 cases of the syndrome reported by Anderson et al. (1967), Lile et al. (19681, Murphy (1969), Rater et al. (1968), and Wallace et al. (1973); these data contradict the 30% incidence summarily reported by Temtamy and McKusick (1978:255-256), a figure also out of line with the review of Gorlin et al. (1965).