Chromosome Xq duplication is a chromosome abnormality that affects many different parts of the body. People with this condition have an extra copy of the genetic material located on the long arm (q) of the X chromosome in each cell. The severity of the condition and the associated signs and symptoms vary based on the size and location of the duplication; the genes involved; and the sex of the affected person. In general, males are typically more severely affected than females and often experience intellectual disability, developmental delay, short stature, abnormalities of the reproductive organs, and distinctive craniofacial features. Many females with this duplication do not have any symptoms or are only affected with short stature; however, some may be just as severely affected as males with the condition. Most cases are inherited in an X-linked manner, often from a mother with no signs or symptoms of the condition.