XLMR genes: update 1996

Am J Med Genet. 1996 Jul 12;64(1):147-57. doi: 10.1002/(SICI)1096-8628(19960712)64:1<147::AID-AJMG25>3.0.CO;2-M.


A current list of all known forms of X-linked mental retardation (XLMR) and a slightly revised classification are presented. The number of known disorders has not increased because 6 disorders have been combined based on new molecular data or on clinical grounds and only 6 newly described XLMR disorders have been reported. Of the current 105 XLMR disorders, 34 have been mapped, and 18 disorders and 1 nonspecific XLMR (FRAXE) have been cloned. The number of families with nonspecific XLMR with a LOD score of > or = 2.0 has more than doubled, with 42 (including FRAXE) now being known. a summary of the localization of presumed nonspecific mental retardation (MR) genes from well-studied X-chromosomal translocations and deletions is also included. Only 10-12 nonoverlapping loci are required to explain all localizations of nonspecific MR from both approaches. These new trends mark the beginning of a significantly improved understanding of the role of genes on the X chromosome in producing MR. Continued close collaboration between clinical and molecular investigators will be required to complete the process.

Publication types

  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Chromosome Mapping
  • Cloning, Molecular
  • Genetic Diseases, Inborn / genetics
  • Genetic Linkage*
  • Humans
  • Intellectual Disability / genetics*
  • X Chromosome*