What is (are) 22q11.2 duplication syndrome ?
22q11.2 duplication syndrome is a condition caused by an extra copy of a small piece of chromosome 22 which contains about 30 to 40 genes. The features of this condition vary widely, even among members of the same family (intrafamilial variability). Affected individuals may have intellectual or learning disability, developmental delay, slow growth leading to short stature, and weak muscle tone (hypotonia). Many people with the condition have no apparent physical or intellectual disabilities. It is inherited in an autosomal dominant manner, with about 70% genes of affected individuals inheriting the condition from a parent. In other cases it occurs as a de novo mutation (new genetic change) in an individual; however, individuals with a de novo mutation can can pass the duplication to their children. Researchers are working to determine which duplicated genes may contribute to the developmental delay and other problems that sometimes affect people with this condition. Duplication is not detectable by karyotype and most of the people with 22q11.2 duplication syndrome are identified by a special technique known as chromosomal microarray. Treatment depends on the symptoms and includes an individualized educational program. Read more out chromosome 22.