Is 1q21.1 microdeletion inherited ?
1q21.1 microdeletion is inherited in an autosomal dominant pattern, which means that missing genetic material from one of the two copies of chromosome 1 in each cell is sufficient to increase the risk of delayed development, intellectual disability, and other signs and symptoms.  In at least half of cases, individuals with a 1q21.1 microdeletion inherit the chromosomal change from a parent. In general, parents who carry a 1q21.1 microdeletion have milder signs and symptoms than their children who inherit the deletion, even though the deletion is the same size. About one-quarter of these parents have no associated features.  A 1q21.1 microdeletion can also occur in people whose parents do not carry the chromosomal change. In this situation, the deletion occurs most often as a random event during the formation of reproductive cells (eggs or sperm) in a parent or in early embryonic development.