Symphalangism

Symphalangism
Specialty	Orthopedics, Genetics
Symptoms	Fusion of joints in fingers or toes
Usual onset	Congenital
Duration	Lifelong
Types	Proximal, distal
Causes	Genetic mutation
Risk factors	Family history
Diagnostic method	Physical examination, X-ray
Treatment	Physical therapy, surgery
Frequency	Rare

Symphalangism is a rare medical condition characterized by the fusion of the joints in the fingers or toes, leading to restricted movement or immobility in the affected digits. This condition can be either congenital, meaning present from birth, or acquired due to other medical conditions or trauma. The primary form of symphalangism is often associated with genetic factors and can be part of several genetic syndromes.

Classification

Symphalangism is classified based on the location of the fused joints:

• Proximal symphalangism: Involves the fusion of the proximal interphalangeal joints (the first joints of the fingers or toes).
• Distal symphalangism: Involves the fusion of the distal interphalangeal joints (the last joints of the fingers or toes).

Causes

The condition is most commonly caused by mutations in specific genes, including the NOG gene which encodes the noggin protein, important for joint development. It can be inherited in an autosomal dominant manner, meaning only one copy of the altered gene is sufficient to cause the disorder.

Symptoms

Symptoms of symphalangism include:

• Lack of flexibility in the affected fingers or toes
• Visible fusion of joints
• Possible pain or discomfort with attempted movement

Diagnosis

Diagnosis of symphalangism typically involves a physical examination and confirmation through imaging techniques such as X-rays, which can clearly show the fusion of joints.

Treatment

Treatment options for symphalangism are limited and focus primarily on managing symptoms and improving joint function. These may include:

• Physical therapy to maximize the range of motion
• Surgical intervention to separate fused joints, although this is complex and not always recommended

Prognosis

The prognosis for individuals with symphalangism varies depending on the severity of the joint fusion and the success of treatment interventions. While mobility can be improved, complete normal function is rarely restored.

See also

• Ankylosis
• Arthrogryposis
• Genetic disorder

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