Lesch-Nyhan syndrome is a rare X-linked genetic disease caused by a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT).
Affects 1 per 380,000 individuals, which are nearly all male given the X-linked inheritance 1.
- hyperuricemia-related symptoms such as gouty arthritis and uric acid nephrolithiasis 1,2
- neurological symptoms which can include extrapyramidal signs such as choreoathetosis and dystonia as well as cognitive defects 1,2
- classic self-mutilating behaviors 1,2
X-linked inherited absence of the nucleotide salvage enzyme HPRT leads to pathologic accumulation of uric acid as hypoxanthine, which would otherwise be recycled into nucleotides, is degraded into uric acid by xanthine oxidase 1.
Ultrasound of the renal tract shows:
- increase in medullary echogenicity, which may be diffuse or patchy 3
- increase in collecting system echogenicity 3
- multiple uric acid stones 3
Brain CT or MRI shows decreased cerebral volume with a predilection for white matter 4.
History and etymology
Discovered in 1946 by Michael Lesch, an American medical student at Johns Hopkins University, and his mentor William Nyhan, a pediatrician and geneticist 1.
- 1. Rosa J Torres, Juan G Puig. Hypoxanthine-guanine phosophoribosyltransferase (HPRT) deficiency: Lesch-Nyhan syndrome. (2007) Orphanet Journal of Rare Diseases. 2 (1): 1. doi:10.1186/1750-1172-2-48 - Pubmed
- 2. Jinnah HA, Visser JE, Harris JC, Verdu A, Larovere L, Ceballos-Picot I, Gonzalez-Alegre P, Neychev V, Torres RJ, Dulac O, Desguerre I, Schretlen DJ, Robey KL, Barabas G, Bloem BR, Nyhan W, De Kremer R, Eddey GE, Puig JG, Reich SG. Delineation of the motor disorder of Lesch-Nyhan disease. (2006) Brain : a journal of neurology. 129 (Pt 5): 1201-17. doi:10.1093/brain/awl056 - Pubmed
- 3. D. L. Rosenfeld, M. P. Preston, K. Salvaggi-Fadden. Serial renal sonographic evaluation of patients with Lesch-Nyhan syndrome. (1994) Pediatric Radiology. 24 (7): 509. doi:10.1007/BF02015015
- 4. Schretlen DJ, Varvaris M, Vannorsdall TD, Gordon B, Harris JC, Jinnah HA. Brain white matter volume abnormalities in Lesch-Nyhan disease and its variants. (2015) Neurology. 84 (2): 190-6. doi:10.1212/WNL.0000000000001128 - Pubmed