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The kniest swiss cheese cartilage syndrome.

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Description of a Distinct Arthropathy
A boy with the Kniest (Swiss cheese cartilage)
syndrome is reported and the salient features of this
rare chondrodystrophy are described. The unique polyarthropathy of this syndrome is characterized by symmetrical bony joint enlargements and fixed flexion contractures significantly contributing to the incapacitating
nature of the disease.
In 1952 Kniest described a young girl with an
unusual syndrome characterized by disproportionate
dwarfism, kyphoscoliosis, a peculiar flat and rounded
facies, deformed extremities, and distinctively enlarged
articular structures that were limited in motion ( I ) . The
Kniest (Swiss cheese cartilage) syndrome-thus far reported in 15 patients (I-6)-proved to be a well defined
chondrodystrophy with established chondrosseous histopathology and roentgenographic findings. Whereas a
characteristic arthropathy constitutes a cardinal manifestation of the syndrome, a search in the rheumatologic
literature failed to reveal a description of this condition.
From the Departments of Internal Medicine, Radiology, and
Pediatrics, American University of Beirut Hospital, Beirut, Lebanon.
Rida Frayha, MD: Assistant Professor of Medicine, Rheumatology Section, Department of Internal Medicine; Rafic Melhem,
MD: Head, Department of Radiology; Hassan Idriss, MD: Clinical
Professor of Pediatrics.
Address reprint requests to R. Frayha, MD, Department of
lnternal Medicine, American University Medical Center, Beirut,
Submitted for publication June 13, 1978; accepted in revised
form September 11, 1978.
Arthritis and Rheumatism, Vol. 22, No. 3 (March 1979)
Reported herein is a patient with the Kniest syndrome who demonstrated the classic clinicoradiologic
stigmata of the disease, including a unique arthropathy
most pronounced over the hands. He also exhibited
neurosensory hearing loss and ptosis of the left upper
MS (AUH 366630), a 9-year-old boy born to nonconsanguineous parents, was admitted to our hospital in 1977
for evaluation of unusual short stature and articular contractures. He could walk at the age of one year, and similarly,
other milestones of motor activity were not delayed and intelligence remained normal. At the age of 2 years he underwent correction of genu varum in another hospital, followed 3
years later by correction of bilateral genu valgum. Between
the ages of 5 and 9 years, progressive painless flexion contractures of the elbows, knees, and hips developed which prevented satisfactory ambulation. At the age of 7. it was noted
that he had painless symmetrical knobby enlargements of the
small joints of the hands with resultant inability to form a fist.
At no time did he experience joint stiffness on inactivation.
Decreased hearing and a narrow left palpebral fissure were
present since birth. He had not suffered from recurrent respiratory infections or otitis media. None of his 3 siblings has a
similar illness.
T h e striking features o n examination were disproportionate dwarfism (height was 122 cm with a short and
wide barrel shaped chest), marked dorsal kyphosis, a flattened
and rounded face with prominent eyes and broad mouth (Figure 1). The palate was high arched but without a cleft. Oph-
thalmologic evaluation revealed no evidence of a refraction
error, but the left palpebral fissure was 3 mm narrower than
the right and there were 6 mm of levator action on the left.
There was no abdominal visceromegaly and the cardiopulmonary and neurologic examinations were normal. His intellectual abilities were normal for his age.
Musculoskeletal examination. The prominent feature
evidenced by the musculoskeletal examination was nontender
and remarkably symmetrical articular bony growth involving
all the distal and proximal interphalangeal (DIP and PIP)
joints, both knees and elbows, resulting in a characteristic
knobby appearance (Figure 2). The h g e r s were elongated
with limited flexion at the metacarpophalangeal and interphalangeal levels resulting in a poor fist. Inflammatory signs,
in particular synovial thickening and fluid, were lacking. Both
hips had 30 degree flexion contractures. Abduction was virtually absent and with the flexion contracture of both knees resulted in a waddling gait. The feet were flat. After many
weeks of an intensive physical therapy program, no improvement in the movement of the lower extremities was achieved.
Laboratory data. The following results of laboratory
tests were normal or negative: hemogram, ESR, urinalysis,
routine blood chemistries including calcium, phosphorous,
and alkaline phosphatase, protein immunoelectrophoresis, LE
cell preparation, antinuclear antibodies, RA latex, and
VDRL. Twenty-four hour urinary excretion of mucopolysaccarides by the method of DiFerrante (7) was normal.
Audiogram revealed neurosensory hearing loss.
A survey of the whole skeleton showed evidence of
diffuse changes in the peripheral joints consisting of symmetrical enlargement of the articular structures due to widening
of the metaphyseal ends. The epiphyseal centers were irregularly ossified. The hands showed characteristic changes of
marked widening of the metaphyseal areas, irregularity of the
ossification centers, and narrowing of the joint spaces. The
carpal bones were large and irregular (Figure 3). The capital
femoral epiphyses were bulky and also irregularly ossified.
The spine showed marked diminution in the height of the vertebrae with gross irregularity of their superior and inferior
margins (Figure 4).These changes were most obvious over the
dorsal and upper lumbar segments. Both iliac bones were
hypoplastic and there was narrowing of the midpelvis.
The composite picture of disproportionate
dwarfism with a short and barrel shaped chest, gross
kyphoscoliosis, flexion contractures of the peripheral
joints secondary to bony enlargement of the articular
surfaces, round and flattened facies with prominent eyes
and broad mouth, high arched palate, and hearing loss
constitutes the clinical hallmarks of the newly recognized chondrodystrophy of Kniest. Myopia, which has
been described in some of the patients (6),was not manifest in this boy who had, instead, congenital unilateral
ptosis: a new manifestation of this syndrome. The present patient did not suffer from recurrent respiratory
Figure 1. Patient MS. Note the wide and barrel shaped chest and
kyphoscoliosis. There are flexion contractures of the elbows, hips, and
knees. The feet are flat and turned out. Other characteristic features
include a flat wide nasal bridge and rounding of the angle of the jaw.
tract infections and otitis media, complications that
have been reported to occur rather commonly in this
disease (6). The diagnosis of Kniest syndrome could he
made at birth should the characteristic features of short
stature, deformed limbs, and enlarged joints be present.
The appearance of the joints is unique for this
syndrome. The small and large joints of the upper and
Figure 2. The prominent findings in the hand are symmetrical bony-hard knobby enlargements at the interphalangeal
joints most pronounced over the second and third proximal interphalangeal ones. The fingers appear long.
lower extremities are symmetrically enlarged with fixed
flexion contractures, the latter being most marked over
the elbows, knees, and hips. The arthropathy of the minor joints of the hands, mainly the PIP and DIP joints,
gives the hand remarkable features; the fingers look
elongated and are knobby in a symmetrical fashion at
the interphalangeal levels (3-6). Such a picture superficially simulates the hand in degenerative joint disease
with multiple Heberden’s and Bouchard’s nodes. Notable is the absence of soft tissue hypertrophy overlying
the bony-hard enlargements of these joints.
The roentgenogram of the hand is also characteristic of Kniest syndrome (6). When the patient is under one year of age, the x-ray findings are normal, but
when the epiphyseal centers of the metacarpals and
phalanges appear, roentgenographic abnormalities become evident. Epiphyseal ossification is delayed; there
is generalized osteopenia. Increased density at all the interphalangeal joints is most marked at the PIP level,
where fragmented accessory ossification centers are seen
mainly over the distal phalanges. By the patient’s sixth
year of age, the joint spaces are narrowed including the
intercarpals and large malformed carpal centers are
seen. The epiphyses, especially of the metacarpals, be-
come flat on the side opposite the epiphyseal plate.
Later, both ends of the bones in the hand show bullous
enlargements. This characteristic flattened and squared
off epiphyses of the hand with joint space narrowing
help to distinguish Kniest syndrome from spondyloepiphyseal dysplasia congenita and other dysplasias. Other
characteristic radiologic findings in Kniest syndrome include platyspondylitis with elongated bodies and vertical clefts in the young and waviness of the superior and
inferior surfaces in adolescents.
The chondrosseous histology is distinctive and
differs from that of other chondrodystrophies (3,4). The
cartilage is friable and irregular in both cellular size and
matrix staining. Some of the cells within the cartilage
are hypertrophic and surrounded by a loose matrix containing large holes resembling Swiss cheese. Because the
cartilage in the growth plate is extremely hypercellular
with little matrix, broad and irregular spicules of calcified cartilage and bone develop. Ultrastructural studies
of this cartilage reveal chondrocytes with markedly dilated cisternae of the endoplasmic reticulum containing
finely granular electron opaque contents. Focal microscars containing large collagen bundles may be seen.
These findings suggested to Rimoin et a1 that the abnor-
Figure 3. The characteristic roentgenogram of the hand. Note the
marked widening of the metaphyses, the irregularity of the ossification centers, the narrowing of the joint spaces (including the intercarpals), and the malformation of the carpal bones.
mality in the cartilagenous structure may be a defect in
collagen metabolism (4).
In summary, the Kniest syndrome is recognized
as a clinical triad of disproportionate dwarfism, enlarged joints with fixed contractures, and a characteristic facies coupled to the distinctive radiologic features
of shortened tubular bones with metaphyseal flaring,
epiphyseal delay, and platyspondylitis with vertebral irregularity.
1. Kniest W: Zur Abgrenzung der Dysostosis enchondralis
von der Chondrodystophie. Ztschr Kinderh 70:633-640,
2. Maroteaux P, Spranger J: La maladie de Kniest. Arch
Franc Pediatr 30:735-750, 1973
3. Rimoin DL, Hollister DW, Silberberg R, Lachman RS,
Figure 4. Lateral view of the dorsal spine illustrating the diminution
in the height of the vertebrae and the irregular superior and inferior
McAlister W, Kaufman R: Kniest (Swiss cheese cartilage)
syndrome: clinical, radiographic, histologic and ultrastructural studies. Clin Res 21:296, 1973
Rimoin DL, Hollister DW, Siggers D, Silberberg R, Lachman RS, McAlister W, Kaufman R, Mckusick V, Dorst J:
Clinical, radiologic, histologic and ultrastructural definition of Kniest syndrome. Pediatr Res 7:348, 1973
Spranger J, Maroteaux P: The Kniest syndrome. Birth Defects, Original Article Series X (12):SO-56, 1974
Lachman RS, Rimoin DL, Hollister DW, Dorst J, Siggers
D, McAlister W, Kaufman R, Langer L: The Kniest syndrome. Am J Roentgenol 123:805-814, 1975
DiFerrante N, Rich C: The determination of acid aminopolysaccharide in urine. J Lab Clin Med 48:491494, 1956
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syndrome, swiss, cartilage, cheese, kniest
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