Acropectoral syndrome

Overview

Acropectoral syndrome is a rare genetic disorder characterized by malformations of the limbs (especially the hands and feet) and abnormalities of the pectoral (chest) muscles. It belongs to a broader group of conditions known as limb malformation syndromes and shares similarities with other disorders affecting limb development, such as Holt-Oram syndrome. Individuals with acropectoral syndrome typically present with preaxial polydactyly

Causes

Acropectoral syndrome is caused by mutations in the GLI3 gene, a gene that plays a critical role in embryonic development, especially the patterning of limbs and other body structures. The condition is inherited in an autosomal dominant pattern, meaning only one copy of the altered gene is sufficient to cause the syndrome. Affected individuals have a 50% chance of passing the condition on to their children.

Symptoms

The symptoms of acropectoral syndrome can vary in severity and may involve one or both sides of the body. Common features include:

• Preaxial polydactyly: Presence of extra digits on the thumb or great toe side

• Bifid thumbs: A split or duplicated thumb

• Hypoplasia or aplasia of the pectoral muscles: Underdevelopment or absence of the chest muscles, especially the pectoralis major

• Shortened or abnormally shaped fingers or toes

• Possible clavicle or shoulder anomalies: In some cases

Unlike other syndromes involving the chest wall (e.g., Poland syndrome), acropectoral syndrome does not typically involve internal organ defects or significant systemic abnormalities.

Diagnosis

Diagnosis is based on physical examination and confirmed through genetic testing. Diagnostic steps include:

• Clinical assessment: Identification of limb anomalies and chest wall underdevelopment

• Family history: Often positive for similar limb defects in an autosomal dominant pattern

• Imaging studies: X-rays of the hands, feet, and chest to evaluate bone and muscle structure

• Genetic testing: Detection of mutations in the GLI3 gene confirms the diagnosis

Treatment

There is no cure for acropectoral syndrome, but many of its physical features can be managed through supportive and surgical care. Treatment options include:

• Orthopedic surgery: To correct polydactyly, bifid thumbs, or improve hand and foot function

• Physical and occupational therapy: To enhance motor skills and adaptive function

• Cosmetic or reconstructive surgery: In cases where chest wall asymmetry causes aesthetic or functional concerns

• Genetic counseling: For families planning to have children, given the hereditary nature of the syndrome

Prognosis

The prognosis for individuals with acropectoral syndrome is generally excellent. The condition does not typically affect intellectual development or life expectancy. With appropriate medical and surgical care, most individuals lead normal, active lives. Functional outcomes are very good, especially when early intervention is provided for limb anomalies.