Arthrogryposis like disorder

Synonyms

3

Overview

It 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.

Symptoms

The range and and severity of signs and symptoms in individuals with Kuskokwim disease can vary, even among siblings. Affected individuals usually have congenital contractures, especially of lower extremities, which progress during childhood and persist for the lifetime of the individual. However, not all individuals with the condition have contractures at birth. The severity of contractures can be very asymmetrical in any given individual. The knees and elbows are often affected, and skeletal abnormalities of the spine, pelvis, and feet also commonly occur. Muscle atrophy of limbs with contractures and displacement of kneecaps (patellae) have also been reported.

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.

General Symptoms:

  • Abnormal gait
  • Absent kneecap
  • Abnormal kneecap
  • Restricted joint mobility
  • Talipes varus
  • Talipes valgus
  • Knee joint contractures
  • Ankle joint contractures
  • Wasting of leg muscles
  • Overgrowth of leg muscle
  • Gait disturbance
  • Limitation of joint mobility
  • Patellar aplasia
  • Aplasia/Hypoplasia of the patella
  • Joint stiffness

Treatment

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.

Resources

  • NIH