Diastrophic dwarfism is a skeletal dysplasia that affects cartilage and bone development. Individuals with diastrophic dwarfism have short stature, with short arms and legs. Affected individuals may also have osteoarthritis and joint contractures. Diastrophic dwarfism is also characterized by the following deformities:
- Scoliosis (abnormal curvature of the spine)
- Hitchhiker thumb (shortening of the first metacarpal)
- Cleft palate
- Malformed ear cartilage
Diastrophic dwarfism is related to the skeletal disorder, atelosteogenesis, albeit less severe.
Diastrophic dwarfism is quite rare, occurring in 1 in 100,000 live births. It has been linked to mutations in the SLC26A2 gene, which provides instructions for making proteins necessary for the normal development of cartilage, and the conversion of cartilage to bone. Mutations to the SLC26A2 gene interfere with the normal development of cartilage to bone, resulting in the skeletal abnormalities characteristic of diastrophic dwarfism. The SLC26A2 gene is inherited recessively; therefore, affected individuals have both copies of the gene. The parents each carry a single copy of the recessive gene and typically do not show any symptoms.
At the Paley Institute we treat these patients with reconstruction of the hip, knee, and foot. Limb lengthening is sometimes performed to increase stature; however, lengthening is not always indicated due to the severe joint problems in these patients.