A family with severe X-linked arthrogryposis.

Five males are reported with severe X-linked arthrogryposis. Main findings are marked respiratory insufficiency and feeding problems, multiple contractures, deformities of chest and vertebral column, and typical facies. Most of these findings can be explained by a pronounced prenatal and postnatal muscle weakness. The sole living child has severe psychomotor retardation. Several female carriers show mild features (clubfeet, contractures, hyperkyphosis, and slight muscle weakness). One manifesting carrier is affected more severely (multiple contractures, mental retardation, and various dysmorphic features). Additional investigations including muscle biopsy revealed none of the usual signs of denervation, and pointed to the presence of a degenerative muscle disorder.