Typical hand deformities include brachydactyly and symphalangism of the proximal joints of the second through fifth fingers. The thumbs are proximally placed and sub luxed in abduction. This feature is known as hitchhiker thumb. The toes are also affected in the same manner. The phenotypic expression varies from mild to severe forms of disease 1-4 .
Affected individuals can achieve normal intellectual development.
The occurrence is undetermined, but it is one of the more common skeletal dysplasias 5 . Six cases have been prenatally diagnosed up to now. Autosomal recessive 1 . Destructive process characterized by disorganization and degeneration of the chondrocytes in the resting cartilage. The cartilage matrix contains a decreased amount of collagen fibers, large cystic areas of fibrous tissue and sometimes ossification.