What is interstitial duplication 15?
People born without an extra chromosome but who have a segment of duplicated material within chromosome 15 are said to have an interstitial duplication. Most often this is the same section (15q11-13) that makes up the extra chromosome in idic(15). For this reason, people with interstitial duplications of 15q and those with idic(15) share similar characteristics. For both conditions, there is a wide range of severity from one person to the next; as a group however, people with interstitial duplication 15 tend to have milder symptoms than those with idic(15). Generally, people with duplications of chromosome 15q do not have family members with the chromosome abnormality. The duplication usually forms by chance in one person in the family. Children with chromosome 15q duplications are born to parents of every socioeconomic, racial, and ethnic background. There is no known link between chromosome 15q duplications and environmental or lifestyle factors. In other words, there is nothing that
