11q

11q refers to the long arm of human chromosome 11 in cytogenetic notation. Chromosomes are divided into a short arm (p) and a long arm (q) by the centromere; regions are designated by numbers that describe their position along the arm. For example, 11q23 designates a specific subregion of the long arm of chromosome 11. This nomenclature is used in karyotypes, genome mapping, and diagnostic reporting to describe the location of genes, deletions, duplications, or translocations.

In clinical genetics, 11q is notable for several regions and rearrangements. The 11q23 region contains the MLL gene (also called KMT2A); rearrangements of this locus, such as translocations involving 11q23, are common in various leukemias and have diagnostic and prognostic significance. The 11q13 region is another area prone to copy-number changes in cancer, with amplification of genes including CCND1 observed in several carcinomas. Terminal deletions of 11q can cause Jacobsen syndrome (11qter deletions), a rare developmental disorder characterized by distinctive facial features, growth delays, and thrombocytopenia. Deletions of 11q have also been reported in neuroblastoma and other cancers, reflecting the region’s contribution to cancer biology.

11q abnormalities are identified and described using standard cytogenetic nomenclature and are interpreted in the context of the patient’s clinical presentation and other laboratory findings. They contribute to diagnosis, prognosis, and, in some cases, targeted therapeutic considerations.