Kuskokwim disease is a congenital (present at birth) contracture disorder that occurs solely among Yup'ik Eskimos in and around the Kuskokwim River delta region of southwest Alaska. Affected individuals usually, but not always, have congenital contractures of large joints (especially knees and/or elbows) and spinal, pelvic, and foot deformities. Other skeletal features have also been reported. Kuskokwim disease has been shown to be caused by mutations in the FKBP10 gene and is inherited in an autosomal recessive manner.

Milder skeletal features are common. Vertebral features may include spondylolisthesis, mild to moderate scoliosis, and/or lordosis. Many affected individuals have had several low-energy fractures. Other skeletal abnormalities that have been reported include bunions (hallux valgus), "flat feet" (plano valgus feet), and clubfoot (talipes equinovarus). Development and arrangement of the teeth (dentition) are normal.

Although some individuals with full bilateral contractures of the knees can move about by “duck walking” (sitting with buttocks on their heels) or by “knee walking” (moving on their knees with their lower legs drawn up behind them to their buttocks), most affected individuals are treated with leg braces and/or surgery in childhood and can walk upright.

Treatment for Kuskokwim disease depends on the nature and severity of signs and symptoms in each affected individual. There is currently no completely successful approach to treat arthrogryposis. The goals of treatment may include lower-limb alignment, establishing stability for ambulation (moving about) and improving upper-limb function for self-care. Many individuals with Kuskokwim disease are treated with leg braces and/or surgery and eventually are able to walk upright.