15q13.3 Microdeletion Syndrome

15q13.3 microdeletion syndrome is a genetic disorder caused by a deletion of several genes on chromosome 15. When a syndrome is caused by the deletion of several genes, it is also known as a microdeletion syndrome or a contiguous gene deletion syndrome. Individuals with 15q13.3 microdeletion syndrome may have very different signs and symptoms from other affected individuals (even within the same family), or no symptoms at all. Features of the condition may include mild to moderate intellectual disabilities, learning delays, or normal intelligence; autism spectrum disorders; epilepsy (recurring seizures); and mental illness (such as schizophrenia or bipolar disorder). Various dysmorphic (abnormally formed) features have been reported, but there are no consistent physical features among individuals who have the condition. 15q13.3 microdeletion syndrome is caused by a deletion on the long arm of chromosome 15 that spans at least 7 genes and usually includes the CHRNA7 gene.It can be inherited in an autosomal dominant manner with reduced penetrance, or can occur as a new (de novo) deletion. Treatment typically focuses on individual signs and symptoms when possible.