Lesch-Nyhan Syndrome [x] [x]
Lesch-Nyhan syndrome (LNS) is a rare, inherited disorder cause by a deficiency of hypoxanthine-guanine phosphoribosyltransferase (HPRT). The lack of HPRT leads to a build up of uric acid in all body fluids. This can cause severe gout, kidney and bladder stones, poor muscle control, and moderate retardation that shows up in the first year of life. Nervous system and behavioral disturbances are characteristic of this disorder. People with this disorder usually deal with involuntary muscle movements such as flexing, jerking, flailing, and facial grimacing, similar to those seen in Huntington’s disease. Another common feature of LNS is self-mutilating behaviors, such as head banging and finger and lip biting that begin in their second year of life. People with this condition usually can’t walk, require assistance sitting, and are generally wheelchair-bound.
The prevalence of LNS is about 1 in 380,000 individuals, and occurs with similar frequency in all populations. Sufferers prognosis is poor; death is usually caused by renal failure in the first or second decades of life. There are no standard treatments for the neurological aspects of LNS, but symptoms like gout and stones can be treated.
LNS is an X-linked recessive disease (the gene associated with the disorder is located on the X chromosome). Only the mother carries and can pass on the gene. Males are much more frequently affected by LNS as they have only one X-chromosome (only need one mutated gene in each cell to be affected), while females have two X-chromosomes (need two mutated genes in each cell to be affected).