Deletion 5q35 syndrome

Deletion 5q35 syndrome, also known as Sotos syndrome (when caused by NSD1 gene deletion), is a genetic condition resulting from a microdeletion on the long arm of chromosome 5 at band q35. This region contains the NSD1 (Nuclear Receptor Binding SET Domain Protein 1) gene, which is the major gene responsible for Sotos syndrome. The condition is characterized by overgrowth, particularly in childhood, with features including excessive growth in height and head circumference (macrocephaly), a distinctive facial appearance with a long face, broad forehead, sparse frontotemporal hair, downslanting palpebral fissures, and a pointed chin. Affected individuals typically have advanced bone age and intellectual disability ranging from mild to severe, along with developmental delay, particularly in motor and speech milestones. The deletion at 5q35 affects multiple body systems. Neurological involvement includes learning difficulties, behavioral problems (such as ADHD, anxiety, and social difficulties), hypotonia, and seizures in some cases. Cardiac anomalies, renal malformations, and scoliosis may also occur. Neonatal complications can include feeding difficulties and jaundice. Individuals with larger deletions encompassing additional genes beyond NSD1 may have more severe intellectual disability and additional clinical features compared to those with point mutations in NSD1 alone. There is no cure for deletion 5q35 syndrome, and management is supportive and symptom-based. Early intervention programs including speech therapy, occupational therapy, and physical therapy are important for optimizing developmental outcomes. Regular monitoring of growth, cardiac and renal function, and scoliosis screening are recommended. Behavioral and educational support is often needed throughout childhood and into adulthood. Genetic counseling is recommended for affected families to discuss recurrence risks and family planning.

Common questions about Deletion 5q35 syndrome