Dermatoglyphics of American Blacks QUTUB H. QAZI,' HELOUISE C. MAPA AND JAMES WOODS Department of Pediatrics, Downstate Medical Center, 450 Clarkson Auenue, Brooklyn, New York 11203 KEY WORDS Dermatoglyphics Footprints I - Fingerprints . Palmprints - American Blacks ABSTRACT Dermatoglyphics of 100 male and 100 female phenotypically normal Black Americans living in New York City were analyzed. The significant bimanual asymmetry was noted only for patterns in the second and the third interdigital areas of the palms. The significant sex differences included excess of digital arch patterns in females and higher mean finger ridge counts in males. Distribution of dermatoglyphic characteristics of Black Americans in our study was compared to those of Black Americans studied by Steinberg e t al. ('75) and Caucasian Americans studied by Schaumann and Alter ('76). The results show that significant differences in the dermatoglyphics exist not only between the Caucasian and Black subjects but also between the two groups of Black Americans. Abnormal dermatoglyphics have been described in a variety of clinical disorders associated with chromosomal aberrations, other genetically determined diseases and prenatal conditions such as congenital rubella (Schaumann and Alter, '76).Since the abnormal dermal configurations due to disease are only a secondary phenomena superimposed on a primary pattern, in part inherited and variable in different sexes and racial groups, it is essential to evaluate dermatoglyphics of patients against those of a group of normal subjects of the same racial and geographic distribution. There is a paucity of data on the dermatoglyphics of normal Black populations of North America. The present report describes dermatoglyphics of the phenotypically normal American Black subjects living in the New York City. MATERIAL AND METHODS The sample is comprised of 200 phenotypically normal unrelated Black Americans (100 male and 100 female) ranging in age from three years to adult. Prints were obtained of fingers, palms and soles utilizing either Faurot (inkless) or Hollister (ink pad) methods. The patterns were evaluated primarily according to the conventional methods (Cummins and Midlo, '43). Modal types of C AM. J. P m s . ANTHROP., 47: 483-488. lines as described by Plato ('70) were used. The position of the distal axial triradius was expressed as a percentage of the distance of the distally placed palmar axial triradius from the distal wrist crease to the length of the palm measured from the distal wrist crease to the proximal of the middle finger (Walker, '57). RESULTS Digital patterns The frequency distribution of finger patterns of male and female subjects are shown in table 1. There were no significant bimanual differences in either sex. There was an excess of arch patterns on both hands of female subjects compared t o males (p<0.005). In all, 8.2%of finger patterns in females were arches in contrast to only 3.2%in males. The pattern intensity index was 13.04 (6.44, left hands; 6.0, right hands) for males and 12.39 (6.20, left hands; 6.19, right hands) for females. Neither bilateral nor sex differences were observed in the pattern intensity index. Finger ridge counts, a-b-ridge counts and atd angles Although the mean total finger ridge count was higher for the right hand than for the left Reprint Requests t o Dr Qutub H Qazi, Department of Pediatrics, 450 Clarkson Avenue, B m k l y n , New York 11203 483 484 QUTUB H. QAZI, HELOUISE C. MAPA AND JAMES WOODS 9999999? n m m w o o r l m Nrlr-t- 99999999 m o m m o o m m dNc-c- 99999999 rlmmc-oo+* *mmm 99999999 mNc-mNNw= NNww 9999 9999 wwNwcOw*S] mom-$ hand in both sexes (table 21, the differences were not significant. The means of total finger ridge counts of each hand as well as combined ridge counts for both hands were significantly higher in males than the corresponding means in females (p < 0.05). There were neither bimanual nor sex differences in means of a-b ridge counts and atd angles (table 2 ) . Palmar patterns The frequency of occurrence of patterns in hypothenar, thenar/I, I1 interdigital, I11 interdigital and IV interdigital areas of palms are shown in table 3. Neither bimanual nor sex differences were observed for occurrences of patterns in hypothenar, thenari1 and IV interdigital areas. There were no sex differences in frequency of the I1 interdigital patterns which occurred more frequently in the right hand than in the left hand in both sexes; however, in only female subjects the bimanual difference (4%left and 14%right) was significant (p< 0.05). Similarly, although there were no sex differences in occurrence of patterns in the 111 interdigital area, in both sexes, the right hand had a higher (p<0.005) frequency of patterns than the left hand (24% left hands and 48% right hands in males; 18%left hands and 41% right hands in females). The position of the distal axial triradius exceeded 40% of the total palm length (t” triradius) in 1.5% (1% left hands; 2% right hands) in males and 1%left hands; 1%right hands) in females. The C p a l m a r line The C line was present in over 90% of the palms of both sexes (table 4). There were no significant sex differences in the direction of the line. The ulnar direction was more frequent (p<O.O25) in the left hand than in the right hand in males but not so in females. The radial direction was significantly more frequent in right hands than in left hands of males (p<0.005), and also more frequent in right hands than in left hands of females (p<0.05). Palmar creases The Simian crease and its variants were scored following the classification of Hook et al. (’74). The classic Simian crease was found in both hands of 1%of the males and none of 485 DERMATOGLYPHICS OF AMERICAN BLACKS TABLE 2 Mean values of total finger ridge count, maximal atd angle, and a-b ridge count by hand and sex in American Blacks Female (n=2001 Mean-tS.D. Male (n = 200) Mean? S.D. Total finger ridge count a - b ridge count Maximal atdangle Left Right Both hands Left Right Both hand6 59.4k21.0 37.5+ 5.4 45.6? 6.2 62.7220.1 36.8-t 6.3 4 5 . 2 ~6.2 122.0240.1 74.3P11.0 90.8r11.8 53.1 t 22.8 38.1- 6.0 45.4-t 6.1 56.52 22.4 36.72 5.9 44.7- 6.5 109.7- 44.4 74.9211.0 90.1*12.0 TABLE 3 Percentage pattern frequencies on right and left palms of American Blacks Male (n= 100) Hypothenar Thenarll I1 interdigital 111interdigital IV interdigital t” triradius Female In = 100) Left Right Both hands Left Right Both hands 27.0 10.0 12.0 24.0 84.0 1.0 24.0 3.0 19.0 48.0 77.0 2.0 25.5 6.5 15.5 36.0 80.5 1.5 34.0 6.0 4.0 18.0 85.0 1.0 31.0 4.0 14.0 41.0 72.0 1.0 32.5 5.0 9.0 29.5 78.5 1.0 TABLE 4 Percentage dmtrabution of the modal types of C palmar line Ulnar Sex Male(n=100) Female (n=100) Radial of American Blacks Proximal Absent Lefl Right Left and right Left Right Left and right Left Right Left and right 57.0 60.0 40.0 48.0 48.5 54.0 20.0 21.0 42.0 35.0 31.0 28.0 10.0 11.0 12.0 9.0 11.0 10.0 Left Right 13.0 6.0 8.0 8.0 Left and right 9.5 8.0 TABLE 5 Percentage frequencies of hallucal patterns an American Blacks Female In= 100) Male (n = 1001 Patterns Arch tibial Small loop dmtal Large loop distal Vestigeal loop distal Loop tibial Whorl Tented arch Arch fibular LWDfibular Opekieldiopen field Left Right 1.0 2.0 10.0 2.0 20.0 59.0 0.0 0.0 0.0 6.0 0.0 2.0 16.0 3.0 19.0 55.0 0.0 0.0 2.0 3.0 the females; it occurred unilaterally in 1%of the males and 1.5%of the females. The Simian crease variants were found only unilaterally in 3% of males and 1%of females. The complete Sidney line occurred bilaterally in 1% of Left t Right Left Right Left + Right 0.5 2.0 13.0 2.5 19.5 57.0 0.0 0.0 1.0 4.5 0.0 4.0 13.0 0.0 22.0 53.0 0.0 1.0 2.0 5.0 0.0 4.0 19.0 0.0 18.0 52.0 0.0 1.0 1.0 5.0 0.0 4.0 16.0 0.0 20.0 52.5 0.0 1.0 1.5 5.0 the males and unilaterally in 1%and 1.5%of male and female subjects, respectively. Hallucal patterns The plantar hallucal patterns did not show 486 QUTUB H. QAZI, HELOUISE C. MAPA AND JAMES WOODS index (13.04 for males and 12.39 for females versus 11.9 for males and 11.2 for females) than those in the group studied by Steinberg et al. However, the means of total finger ridge counts of our subjects were closely similar (p>0.05) to those found by Steinberg e t al. (119.0, S.D. 41 for males and 106.5. S.D. 47 for females). There were also similarities in freDISCUSSION quencies of palmar patterns in the two popuThe only significant bimanual differences lations. The significant differences were obnoted in the present sample are: (1)a higher served only in the occurrence of patterns in frequency of patterns in the second inter- the Thenar/I (p<0.005) and I11 interdigital digital area in the right hand of females (p<0.025) areas in both sexes. In both in(p< 0.05) and (2) a higher frequency of I11 in- stances the subjects in the other study had terdigital patterns in the right hands of both higher frequency of patterns. Our female subsexes (p < 0.005). These bilateral differences jects had a higher pattern frequency in the have been observed by Steinberg et al. ('75). hypothenar area (p<O.Ol) than the female The significant sex differences included an subjects in the other study. No significant difexcess of digital arch patterns in females ferences were noted in the modal types of C (p<0.05) and a higher mean finger ridge lines and atd angles in the two groups. Comparison of our dermatoglyphic data for count in males (p<0.025). Such sex differences have also been previously described American Blacks with those for North American Caucasians (Schaumann and Alter, '76) (Steinberg et al., '75). In their article, Steinberg e t al. ('75) com- shows significant differences between the two pared t h e dermatoglyphics of American groups. Compared to Caucasians, Blacks in Negroes to the characteristics of Negro popu- our study have (1)higher frequency of whorls lations such as African Bushmen, African and lower frequency of radial loops (p < 0.005) Pygmies and other African Negroes, derived on digits of both sexes, (2) lower frequency of from numerous studies. They found a number ulnar loops (p<0.05) in females and lower freof similarities of dermatoglyphics between quency of arch patterns (p<0.005) in males, different Negro subgroups. Within Negro pop- (3) lower mean total finger ridge count in ulations there was very little variation in males (p<O.OOl), (4) higher frequency of I1 the digital pattern frequencies, although the interdigital and IV interdigital patterns in African Bushmen have higher values of both sexes (p < 0.005) and lower frequency of arches than other subgroups. American Ne- hypothenar patterns in males (p<0.005), (5) groes were found t o be more similar to the lower frequency of ulnar direction of modal other African Negroes than t o the African C-line in females (p<0.05) and lower frequenPygmies or African Bushmen. The modal cy of radial direction of C-line in males types of the C line of the American Negroes (p<O.O25), (6)lower mean a-b ridge count in were similar in frequencies to those of the both sexes (p<O.OOl), (7) higher mean atd African Negroes. The palmar pattern frequen- angle in males (p<O.OOl), and (8) lower frecies of the American Negroes, in general, con- quency of distal loops (p<0.005) and tibial formed to those of the other Negro subgroups. loops (p<0.025) in the hallucal patterns of Our findings of dermal patterns of Ameri- both sexes. Only 1.25% of Black subjects in can Blacks living in the New York area are, to our study had t" triradius compared to 11.8% some extent, similar to those of American of Canadian Caucasians studied by Walker Blacks enrolled in the Collaborative Perinatal ('57). The present study has confirmed the racial Study of the National Institute of Neurological Diseases and Strokes (Steinberg et al., and sex variations in the dermatoglyphics of '75). Both male and female subjects in our Black Americans. Statistically significant study group had a higher frequency of whorls differences in the type and frequency of pat(p< 0.005), lower frequency of ulnar loops terns exist not only between the Caucasian (p<O.Ol), lower frequency of arch patterns and Black subjects, but even among the peo(p<0.05), and a higher pattern intensity ple of apparently similar racial backgrounds either sex or lateral differences (table 5). The three most frequent hallucal patterns were whorls (57% in males and 52.5% in females), tibial loops (19.5% in males and 209: in females) and large distal loops (13%in males and 16% in females). The other hallucal patterns occurred with a frequency of 5%or less. DERMATOGLYPHICS OF AMERICAN BLACKS such as groups of American Blacks studied by Steinberg et al. ('75) and by us. It must be stressed that these differences are important enough that they be taken into consideration while evaluating dermatoglyphics in clinical situations. LITERATURE CITED Cummins, H., and C. Midlo 1943 Finger Prints, Palms and Soles. Blakiston Co., Philadelphia. Hook, E. B., R. Bonenfant, M. L. Powers, M. Greenberg and L. R. Shapiro 1974 The human Simian crease and its 487 variants: a model for investigation of serious congenital malformations. Birth Defects: Original Article Series X, No. 7, 7-16, Plato, C. C. 1970 Polymorphism of the C line: with a new classification of the C line terminations. Am. J. Phys. Anthrop., 33: 413-420. Schaumann, B., and M. Alter 1976 Dermatoglyphics in Medical Disorders. Springer-Verlag, New York, Heidelberg, Berlin. Steinberg, F. S., J. J. Cereghino and C. C. Plato 1975 The dermatoglyphics of American Negroes. Am. J. Phys. Anthrop., 42: 183-194. Walker, N. F. 1957 The use of dermal configurations in the diagnosis of mongolism. J. 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