NCIt definition : An X-linked inherited syndrome caused by mutations in the gene that encodes the enzyme
hypoxanthine-guanine phosphoribosyltransferase, resulting in accumulation of uric
acid in the body. It affects males and is characterized by neurologic defects, moderate
mental retardation, muscle hypotonia, and a tendency for self-mutilation (self-biting
of lips, tongue, and fingertips).;