Diastrophic dysplasia is a rare congenital skeletal dysplasia characterized by disproportionated dwarfism with short extremities and joint malformations. Deformities of the spine and multiple joint contractures, especially shoulders, elbows, interphalangeal and hip joints, often occur.
The final size of adult patients is about 120 ± 10 cm. The children are born with a bilateral clubfoot, deformed wrists and abducted thumbs, so-called "hitchhikers' thumbs". Often there is also a cleft palate and a hypoplastic lower jaw.
In the first months of life, cystic structures develop on the ear cartilage, which later leave a cauliflower-like ear deformity. The growth is slowed down and often there is a progressive kyphoscoliosis.
Joint deformations are associated with limited flexibility or hyperextension. The clinical variability of the clinical picture is considerable and ranges from moderate to very severe courses.
The syndrome is inherited as an autosomal recessive trait. The cause are homozygous mutations in the SLC26A2 / DTDST (diastrophic dysplasia sulfate transporter) gene, which codes for a predominantly cartilage-expressed sulfate transporter.
Occasionally, the disease is lethal at birth, but most affected individuals survive the neonatal period and develop described physical limitations with normal intelligence.
If there are no serious complications associated with spinal cord deformities (spinal cord compression), life expectancy is good. However, those affected are usually exceptionally handicapped and in need of assistance in their daily life.