Distal 7q11.23 microduplication syndrome

Distal 7q11.23 microduplication syndrome (also known as 7q11.23 duplication syndrome or Somerville-van der Aa syndrome) is a rare chromosomal disorder caused by a duplication of a segment of genetic material on the long arm of chromosome 7, in the region distal (farther from the centromere) to the Williams-Beuren syndrome critical region. This microduplication typically spans approximately 1.2 megabases and encompasses several genes that play roles in neurodevelopment and other biological processes. The syndrome primarily affects the nervous system and is characterized by speech and language delay, intellectual disability of variable severity, and behavioral abnormalities including features of autism spectrum disorder, attention deficit, and anxiety. Affected individuals may also present with mild dysmorphic facial features, such as a broad forehead, thin upper lip, and a short philtrum, though facial features can be subtle and variable. Hypotonia (low muscle tone) in infancy, motor developmental delays, and seizures have also been reported in some patients. Growth parameters are generally within the normal range, though some individuals may show mild short stature or macrocephaly. There is currently no specific cure or targeted therapy for distal 7q11.23 microduplication syndrome. Management is supportive and symptom-based, typically involving speech and language therapy, occupational therapy, behavioral interventions, and special educational support. Seizures, when present, are managed with standard antiepileptic medications. Early intervention programs are recommended to optimize developmental outcomes. Genetic counseling is advised for affected families, as the duplication may be inherited from a mildly affected or apparently unaffected parent.

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