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. While many affected people inherit the condition from a parent, others are affected due to having a new mutation that occurs for the first time. In either case, the condition can be passed on to 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. The duplication is not detectable by karyotype and most cases are identified by a technique known as chromosomal microarray. Treatment depends on the symptoms in each person and includes an individualized educational program.