Kuskokwim syndrome

Kuskokwim syndrome is characterized by joint deformities called contractures that restrict the movement of affected joints. This condition has been found only in a population of Alaska Natives known as Yup'ik Eskimos, who live in and around a region of southwest Alaska known as the Kuskokwim River Delta.

In Kuskokwim syndrome, contractures most commonly affect the knees, ankles, and elbows, although other joints, particularly of the lower body, can be affected. The contractures are usually present at birth and worsen during childhood. They tend to stabilize after childhood, and they remain throughout life.

Some individuals with this condition have other bone abnormalities, most commonly affecting the spine, pelvis, and feet. Affected individuals can develop an inward curve of the lower back (lordosis), a spine that curves to the side (scoliosis), wedge-shaped spinal bones, or an abnormality of the collarbones (clavicles) described as clubbing. Affected individuals are typically shorter than their peers and they may have an abnormally large head (macrocephaly).