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7) And many others diseases
will not be
detailed here: arthrogryposis, myelomenigo
cele, chondroosteodystrophy…
Patellaaplasia-
hypoplasia
Patella aplasia-hypoplasia is a rare condition
characterized by the congenital absence or
marked reduction of the patella (but dislocation
is also possible). Aplasia or hypoplasia occurs
classically in nail-patella syndrome, small
patella syndrome, and several other syndromes
(Table 1), but can also very rarely be isolated
[9]. Most common syndromes are:
1) Nail-patella syndrome
(NPS), also called
hereditary osteo-onychodysplasia, is a rare
hereditary autosomal dominant disorder
resulting from a heterogenous loss of function
in the LMXB1 gene on chromosome 9q34. The
clinical manifestations are extremely variable
in both frequency and severity. Patients have a
characteristic tetrad of pathologic symptoms
including aplasia/hypoplasia patellas and iliac
horns (fig. 3),
fingernail dysplasia, and radial
head dislocation
(fig. 4) [12].
Table 1: Differential Diagnoses of Nail-Patella Syndrome according to Sweeney [12].
Syndrome
Similarities
Differences
References
Small patella
syndrome (SPS)
Small or absent patellae
Recurrent patella
dislocations
Pelvic anomalies
Defective ossification at the ischiopubic
junction - Ischial hypoplasia
Infra-acetabular «axe-cut» notch
No nail changes
No elbow changes
No renal involvement
No ocular involvement
OMIM
147891
Patella aplasia-
hypoplasia (PTLAH)
Hypoplasia of the patella
or Isolated aplasia
No nail changes
No elbow changes
No renal involvement
No ocular involvement
OMIM
168860
Familial recurrent
dislocation
of the patella
Familial tendency toward
patella dislocation
OMIM
169000
Meier-Gorlin
syndrome (MGS)
Absent patellae
Dislocation of the radial
head
Microtia
Markedly short stature
Delayed bone age
Characteristic facial appearance
OMIM
224690
Genitopatellar
syndrome (GPS)
Absent patellae
Renal anomalies
Flexion deformities of
the knees and hips
Club foot
Hypoplasia of the ischia and iliac bones
Genital anomalies
Facial dysmorphism
Microcephaly
Intellectual disability
Multicystic kidneys or hydronephrosis
Renal manifestations
OMIM
606170
Trisomy 8
mosaicism
Hypoplastic patellae
Limited elbow supination
Abnormal nails
Significant learning difficulties
Variable facial dysmorphism
Camptodactyly and progressive joint
restriction, usually of the fingers and toes
Jones [1997]
Coffin-Siris
syndrome (CSS)
Absence or hypoplasia
of the nails and patellae
Elbow dislocation
Nail hypoplasia, usually affecting the little
finger nails
Facial dysmorphism
OMIM
135900
RAPADILINO
syndrome
(Rothmund-
Thomson
syndrome)
Radial defects
Absent or hypoplastic
patellae
Dislocated joints
Cleft palate
Facial dysmorphism
Short stature
Radial defects, including absent or
hypoplastic thumbs and radii
OMIM
266280