Arthrogryposis multiplex congenita, distal type 1

Arthrogryposis multiplex congenita, distal type 1
Synonyms	N/A
Pronounce	N/A
Specialty	N/A
Symptoms	Congenital joint contractures
Complications	N/A
Onset	Birth
Duration	Lifelong
Types	N/A
Causes	Genetic mutations
Risks	N/A
Diagnosis	Clinical evaluation, genetic testing
Differential diagnosis	N/A
Prevention	N/A
Treatment	Physical therapy, orthopedic interventions
Medication	N/A
Prognosis	Variable
Frequency	N/A
Deaths	N/A

Arthrogryposis multiplex congenita, distal type 1 (DA1) is a rare genetic disorder characterized by congenital joint contractures that primarily affect the distal parts of the limbs. This condition is part of a broader group of disorders known as arthrogryposis multiplex congenita (AMC), which involves multiple joint contractures present at birth.

Etiology

DA1 is caused by mutations in genes that are involved in the development and function of the musculoskeletal system. The most commonly implicated gene in DA1 is the MYH3 gene, which encodes a protein that is part of the myosin heavy chain. Mutations in this gene disrupt normal muscle development and function, leading to the characteristic joint contractures seen in this condition.

Clinical Features

Individuals with DA1 typically present with:

• Contractures of the hands and feet, such as clubfoot or clenched fists.
• Limited range of motion in affected joints.
• Normal or near-normal muscle strength.
• Absence of significant muscle atrophy.

Unlike other forms of arthrogryposis, DA1 does not usually involve the proximal joints, such as the hips and shoulders, and does not affect the central nervous system.

Diagnosis

Diagnosis of DA1 is primarily clinical, based on the presence of characteristic joint contractures. Genetic testing can confirm the diagnosis by identifying mutations in the MYH3 gene or other related genes. Prenatal diagnosis is possible if there is a known family history of the condition.

Management

Management of DA1 focuses on improving joint mobility and function. This may include:

• Physical therapy to maintain and improve range of motion.
• Orthopedic surgery to correct severe contractures or deformities.
• Use of splints or braces to support affected joints.

Early intervention is crucial to optimize outcomes and improve quality of life.

Prognosis

The prognosis for individuals with DA1 varies depending on the severity of the contractures and the effectiveness of treatment. Many individuals can achieve a good level of function with appropriate management, although some may experience lifelong limitations in joint mobility.

Genetic Counseling

DA1 is typically inherited in an autosomal dominant pattern, meaning that a single copy of the mutated gene is sufficient to cause the disorder. Genetic counseling is recommended for affected individuals and their families to discuss inheritance patterns, risks to future offspring, and available testing options.

Also see

• Arthrogryposis multiplex congenita
• Distal arthrogryposis
• Congenital contractures
• Genetic disorders