Acrocephalosyndactyly

Patient with Apert syndrome

Baby with Crouzon Syndrome (cropped)

Acrocephalosyndactyly is a rare genetic disorder that encompasses a group of conditions characterized by craniosynostosis and syndactyly. Craniosynostosis is the premature fusion of one or more cranial sutures, leading to an abnormal head shape. Syndactyly involves the fusion of two or more fingers or toes. This condition is part of a broader category of disorders known as craniofacial syndromes, which affect the skull and facial bones.

Etiology

Acrocephalosyndactyly is primarily caused by genetic mutations that affect the development of the bones in the skull and limbs. The most common genetic mutations associated with this condition occur in the FGFR (Fibroblast Growth Factor Receptor) genes. These mutations are usually inherited in an autosomal dominant pattern, meaning only one copy of the altered gene in each cell is sufficient to cause the disorder.

Classification

There are several types of Acrocephalosyndactyly, each with distinct characteristics:

• Apert Syndrome: Characterized by craniosynostosis, syndactyly of the hands and feet, and distinctive facial features.
• Crouzon Syndrome: Involves craniosynostosis, with no hand or foot abnormalities but with distinctive facial features.
• Pfeiffer Syndrome: Features craniosynostosis, broad thumbs and big toes, and partial soft tissue syndactyly.
• Saethre-Chotzen Syndrome: Includes craniosynostosis, facial asymmetry, ptosis (drooping of the upper eyelid), and mild syndactyly.

Symptoms

The symptoms of Acrocephalosyndactyly vary depending on the specific type but generally include:

• Abnormal head shape due to craniosynostosis
• Fused fingers or toes (syndactyly)
• Intellectual disability (varies by type and individual)
• Vision problems
• Hearing loss
• Breathing difficulties
• Dental problems

Diagnosis

Diagnosis of Acrocephalosyndactyly is based on physical examination, medical history, and imaging tests such as X-rays or CT scans to assess the extent of craniosynostosis and syndactyly. Genetic testing can confirm the diagnosis by identifying mutations in the FGFR genes or other genes associated with the condition.

Treatment

Treatment for Acrocephalosyndactyly is multidisciplinary and may involve:

• Surgery to correct craniosynostosis and reshape the skull
• Surgery to separate fused fingers or toes
• Orthodontic treatment for dental problems
• Management of vision and hearing problems
• Supportive therapies, such as physical therapy and occupational therapy

Prognosis

The prognosis for individuals with Acrocephalosyndactyly varies widely depending on the severity of the symptoms and the success of treatment interventions. Early diagnosis and treatment can improve outcomes, particularly in terms of cognitive development and quality of life.