22q11.2 duplication syndrome

22q11.2 duplication syndrome is a rare chromosomal disorder caused by a microduplication of a region on the long arm of chromosome 22 (band 11.2). This is the reciprocal genomic rearrangement of the well-known 22q11.2 deletion syndrome (DiGeorge/velocardiofacial syndrome). The duplicated region typically spans approximately 3 megabases and encompasses multiple genes, including TBX1. The condition is also referred to as 22q11.2 microduplication syndrome. Because the clinical presentation is highly variable, some individuals carrying the duplication may have no apparent symptoms, which complicates diagnosis and genetic counseling. The syndrome can affect multiple body systems, though with incomplete penetrance and variable expressivity. Key clinical features may include intellectual disability or learning difficulties (often mild to moderate), developmental delay, speech and language delays, growth retardation, and behavioral abnormalities. Congenital heart defects have been reported in some patients, though less frequently than in the deletion syndrome. Velopharyngeal insufficiency, palatal abnormalities, and urogenital anomalies may also occur. Some individuals present with dysmorphic facial features, which can be subtle and may include hypertelorism, a broad flat nasal bridge, and micrognathia. Hypotonia in infancy is also described. There is no specific cure for 22q11.2 duplication syndrome. Management is symptomatic and supportive, tailored to the individual's clinical presentation. This may include speech therapy, occupational therapy, educational support, cardiac evaluation and management if heart defects are present, and behavioral or psychiatric interventions as needed. Genetic counseling is recommended for affected families, as the duplication can be inherited from a mildly affected or apparently unaffected parent. Regular developmental monitoring is important, particularly in childhood, to ensure early intervention for any emerging difficulties.

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