Sotos

Sotos syndrome, also known as cerebral gigantism, is a rare genetic overgrowth disorder characterized by rapid early growth, macrocephaly, and distinctive facial features, along with developmental delay and varying degrees of intellectual disability. Most affected children are normal at birth but display accelerated growth in infancy and continuing above-average height in childhood.

Clinical features commonly include a long face with a high forehead, sparse frontotemporal hair, a broad nasal bridge, and down-slanting palpebral fissures. Other typical signs are neonatal hypotonia, advanced bone age, and persistent macrocephaly. Developmental delays range from mild to moderate, with speech and motor delays often prominent. Behavioral issues, attention difficulties, and, in some cases, seizures or autistic features may occur. Brain imaging can show megalencephaly or other signs of brain overgrowth, though findings are variable.

Genetically, Sotos syndrome is usually caused by haploinsufficiency of the NSD1 gene on chromosome 1q35. Most cases arise de novo, but familial transmission has been reported. Genetic testing for NSD1 mutations or deletions can confirm the diagnosis and help differentiate it from other overgrowth or neurodevelopmental conditions.

Diagnosis is based on clinical presentation supported by genetic testing. Management is supportive and multidisciplinary, involving developmental and educational interventions, physical, occupational, and speech therapy, and monitoring for associated health issues such as seizures or orthopedic problems. Regular growth and development assessments guide individualized care, with attention to speech and social development.

Prognosis is variable and depends on the level of intellectual disability and associated medical issues. The syndrome was first described in the 1960s and is named after the physician Sotos, who contributed to its early characterization.