15q24 microdeletion is a chromosomal change in which a small piece of chromosome 15 is deleted in each cell. The deletion occurs on the long (q) arm of the chromosome at a position designated q24.
This condition is very rare; only a few dozen affected individuals have been identified.
People with a 15q24 microdeletion are missing between 1.7 million and 6.1 million DNA building blocks (base pairs), also written as 1.7-6.1 megabases (Mb), at position q24 on chromosome 15. The exact size of the deletion varies, but all individuals are missing the same 1.2 Mb region. This region contains several genes that are thought to be important for normal development.
The signs and symptoms that result from a 15q24 microdeletion are probably related to the loss of one or more genes in the deleted region. However, it is unclear which missing genes contribute to the specific features of the disorder.
The identified cases of 15q24 microdeletion have occurred in people with no history of the condition in their family. The chromosomal change likely occurs as a random event during the formation of reproductive cells (eggs or sperm) or in early fetal development.
This entry is adapted from the peer-reviewed paper https://medlineplus.gov/genetics/condition/15q24-microdeletion