Sotos syndrome

A genetic disorder characterized by excessive physical growth during the first years of life

Sotos syndrome, also known as cerebral gigantism, is a rare genetic disorder characterized by excessive physical growth during the first years of life. It is associated with advanced bone age, distinctive facial features, and a variety of developmental delays. The condition is caused by mutations in the NSD1 gene, which plays a role in normal growth and development.

Signs and symptoms

Individuals with Sotos syndrome typically exhibit rapid growth in infancy and early childhood, often resulting in a height and weight significantly above average for their age. Common features include a large head size (macrocephaly), a long face with a high forehead, and a pointed chin. Other facial characteristics may include down-slanting palpebral fissures, a prominent jaw, and a high-arched palate.

Developmental delays are common, particularly in motor skills and speech. Intellectual disability can range from mild to severe, although some individuals have normal intelligence. Behavioral issues, such as attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD), may also be present.

Genetics

Sotos syndrome is primarily caused by mutations in the NSD1 gene located on chromosome 5q35. This gene is responsible for producing a protein that regulates chromatin structure and gene expression, which are crucial for normal growth and development. Most cases of Sotos syndrome are sporadic, resulting from new mutations, but familial cases with autosomal dominant inheritance have been reported.

Diagnosis

Diagnosis of Sotos syndrome is based on clinical features and can be confirmed by genetic testing for mutations in the NSD1 gene. The presence of characteristic facial features, overgrowth, and developmental delays often prompts genetic testing. Advanced bone age, as determined by X-ray, can also support the diagnosis.

Management

There is no cure for Sotos syndrome, and treatment focuses on managing symptoms and supporting development. Early intervention programs, including physical, occupational, and speech therapy, can help address developmental delays. Regular monitoring of growth and development is important, and educational support may be necessary for children with learning difficulties.

Prognosis

The prognosis for individuals with Sotos syndrome varies depending on the severity of symptoms. While physical growth tends to normalize in adulthood, developmental and intellectual challenges may persist. With appropriate support and intervention, many individuals can lead fulfilling lives.

Related pages

• Genetic disorder
• Developmental delay
• Intellectual disability
• NSD1