5q22 microdeletion syndrome

5q22 microdeletion syndrome (Orphanet code 261584) is a rare chromosomal disorder caused by a submicroscopic deletion on the long arm of chromosome 5 at band q22. This region encompasses several genes, most notably the APC (adenomatous polyposis coli) gene, which plays a critical role in tumor suppression and cell signaling. When the deletion includes APC, affected individuals may present with features overlapping with familial adenomatous polyposis (FAP), including a predisposition to developing numerous colorectal polyps and an elevated risk of colorectal cancer. The syndrome is sometimes referred to as a contiguous gene deletion syndrome at 5q22. Because the deletion can vary in size and may encompass multiple adjacent genes, the clinical presentation can be broader than isolated FAP. Patients may exhibit intellectual disability, developmental delay, dysmorphic facial features, and behavioral difficulties depending on the extent of the deletion. Some individuals also present with congenital anomalies and growth abnormalities. The involvement of multiple body systems — including the central nervous system, gastrointestinal tract, and craniofacial structures — reflects the loss of several functionally important genes within the deleted segment. Management is multidisciplinary and tailored to the individual's specific clinical features. Gastrointestinal surveillance with regular colonoscopy is essential for those at risk of polyposis and colorectal cancer, and prophylactic colectomy may be recommended. Developmental support including speech therapy, occupational therapy, and special education services is often needed. Genetic counseling is important for affected families. There is currently no cure for the syndrome; treatment focuses on surveillance, symptom management, and early intervention to optimize developmental outcomes.

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