arthrogryposis, distal, type 2B3

Arthrogryposis, distal, type 2B3 is a condition that primarily affects the musculoskeletal system, leading to joint contractures and alterations in limb function. It is classified among the distal arthrogryposes, where congenital joint stiffness predominantly influences the hands and feet. Variants in the MYH3 gene have been implicated in this condition, and it follows an autosomal dominant pattern of inheritance, meaning that a single altered copy of the gene can be associated with the phenotype. Prevalence data are not specified, and although this condition is present from birth, the clinical features may vary considerably in severity among affected individuals.

Individuals affected by arthrogryposis, distal, type 2B3 typically exhibit distinctive physical features that form the core clinical presentation. Characteristic findings include downslanted palpebral fissures, adducted thumbs, camptodactyly, ulnar deviation of the hand, and a narrow mouth, all of which are noted to be present in 100% of reported cases. These features often contribute to the diagnosis during infancy as parents and clinicians notice challenges related to joint mobility and facial configuration. While these particular signs are always observed, the impact on overall function and appearance can vary, and not all individuals experience every possible complication associated with the condition. In addition, severity and the degree of impairment may differ from one affected person to another, emphasizing that there is a broad spectrum of clinical expression.

The underlying cause of arthrogryposis, distal, type 2B3 is linked to variants in the MYH3 gene. The protein encoded by MYH3 plays an important role in muscle development and function during embryonic growth, and disruptions in this protein can affect the formation and mobility of the limbs. Inherited in an autosomal dominant pattern, a single altered copy of the gene is enough to lead to the condition. That, even among relatives who inherit an affected gene, the specific symptoms and severity can vary considerably, a phenomenon known as variable expressivity. Families are encouraged to consider genetic counseling to better understand the inheritance implications and to discuss how the condition may impact future family planning.

Currently, management of arthrogryposis, distal, type 2B3 focuses on supportive care and symptom management. Because there are no FDA-approved or gene-specific treatments available for this condition, treatment typically revolves around optimizing joint function, addressing any musculoskeletal or functional challenges, and ensuring the best possible quality of life. Intervention strategies may include physical and occupational therapy to maintain mobility and to reduce discomfort, as well as the supportive guidance of a multidisciplinary team experienced in managing musculoskeletal disorders. In addition, families are advised to seek genetic counseling to understand the condition further and to explore all available resources to support individualized care. Treatment plans are tailored to the needs of each patient, and ongoing communication with a healthcare team is essential for monitoring progress and adjusting management as needed.

The outlook for individuals with arthrogryposis, distal, type 2B3 is variable, as the condition may range from relatively mild joint limitations to more significant functional challenges. With current standards of care, many individuals are able to manage their symptoms over a lifetime and maintain a good quality of life, although the degree of disability can differ widely between individuals. Outcomes described in medical literature continue to evolve as standards of care improve, and ongoing advancements in supportive therapies contribute to better long-term management. It is important for families to work closely with specialists and genetic counselors to gain personalized guidance on managing the condition, and patient support groups can offer additional resources and community connection.