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Distal arthrogryposis type 1
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Distal Arthrogryposis Type 1

Distal arthrogryposis type 1 is a rare genetic disorder characterized by congenital joint contractures that restrict movement primarily in the hands and feet.

Overview

Distal arthrogryposis type 1 (DA1) is a condition marked by joint deformities, known as contractures, that limit the range of motion in the distal joints of the limbs. The term "arthrogryposis" derives from Greek roots: arthro-, meaning joint, and gryposis, meaning crooked or hooked. Unlike many other congenital conditions, the signs and symptoms of distal arthrogryposis type 1 typically spare other parts of the body, focusing almost entirely on the hands and feet.

Signs and Symptoms

The specific structural abnormalities in the limbs can vary significantly among affected individuals, but hallmark clinical features include:

  • Permanently bent fingers and toes (camptodactyly)
  • Fingers angled outward toward the fifth digit (ulnar deviation)
  • Inward- and upward-turning feet (clubfoot)
  • Restricted mobility in the small joints of the hands and feet

Causes and Genetics

Distal arthrogryposis type 1 is associated with genetic variants in at least two genes:

  • TPM2
  • MYBPC1

These genes are active in muscle tissue, where their encoded proteins interact with other muscle proteins to regulate the tensing and contraction of muscle fibers. While the exact molecular mechanism remains under investigation, researchers suggest that impaired muscle contraction limits joint movement prior to birth, leading to joint contractures. In some affected individuals, the precise genetic cause remains unidentified, and research into additional genetic factors is ongoing.

Inheritance

This disorder is inherited in an autosomal dominant pattern. Under this mode of inheritance, a single copy of the altered gene in each cell is sufficient to cause the condition. Many individuals diagnosed with distal arthrogryposis type 1 have an affected parent and other close relatives with the disorder.

Prevalence

Distal arthrogryposis type 1 is estimated to affect approximately 1 in 10,000 individuals worldwide.

Alternative Names

  • AMCD1 (Arthrogryposis Multiplex Congenita, Distal, Type 1)
  • Arthrogryposis, distal, type 1
  • DA1

Frequently Asked Questions

Distal arthrogryposis type 1 (DA1) is characterized by contractures predominantly restricted to the hands and feet, featuring camptodactyly, ulnar deviation of the fingers, hypoplastic flexion creases, and clubfoot. Unlike other distal arthrogryposis forms (such as Sheldon-Hall or Freeman-Sheldon syndromes), DA1 generally lacks prominent facial abnormalities (like a whistling face appearance or downslanting palpebral fissures), cleft palate, or significant contractures involving major proximal joints such as the hips and shoulders.
No, distal arthrogryposis type 1 does not affect cognitive function, brain development, or internal organ systems. Children have normal intelligence and a standard life expectancy. The condition is non-progressive, meaning the underlying muscle contractures do not spontaneously worsen, although secondary joint stiffness or degenerative changes can develop if early physical rehabilitation and positioning therapies are neglected.
Distal arthrogryposis type 1 is inherited in an autosomal dominant pattern, which means an affected parent has a 50 percent chance of passing the responsible genetic variant (such as in TPM2 or MYBPC1) to each child. However, the condition displays variable expressivity; an affected child may exhibit more severe or much milder joint contractures than their parent.
Intervention should begin immediately after birth with conservative orthopedic and physical therapies. Serial casting, notably the Ponseti method, is standard for correcting clubfoot deformities. Daily passive stretching regimens, occupational therapy, and specialized thermoplastic splinting help improve hand mobility, encourage thumb abduction, and preserve finger range of motion. Surgical tendon releases, osteotomies, or capsulotomies are reserved for fixed deformities that fail to respond to physical modalities.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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