Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0012872 (DNA marker)
 929 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Retinitis pigmentosa (RP) is an hereditary degenerative disease of the retina and a major cause of visual impairment, prevalence estimates ranging from 1 in 3000 to 1 in 7000. The condition may segregate as an autosomal dominant, autosomal recessive or an X-linked recessive trait and it may also occur on a sporadic basis in up to 50% of cases. In the autosomal dominant form, close linkage to the DNA marker C17 (D3S47) was recently established in a large family of Irish origin displaying early-onset disease (McWilliam et al. 1989), multipoint analysis indicating the gene for rhodopsin as a likely candidate (Farrar et al. 1990). In that gene, a C----A transversion in codon 23, resulting in a proline----histidine substitution has now been identified in 17 of 148 unrelated ADRP patients in the United States (Dryja et al. 1990). This mutation is absent however in the original Irish pedigree (it is also absent in 21 other dominant Irish pedigrees, representing approximately 70% of the estimated ADRP population) indicating that another mutation, either in rhodopsin itself, or in a gene very closely linked to rhodopsin is responsible for the disease in that family. Analysis of other dominant pedigrees using the C17 and/or rhodopsin probes has indicated either tight linkage (Bhattacharya, Personal Communication), looser linkage, possibly indicative of a second locus on 3q (Olsson et al. 1990) or no linkage (Farrar et al. 1990, Blanton et al. 1990, Inglehearn et al. 1990). Extensive genetic heterogeneity thus exists in the autosomal dominant form of this disease, and in the light of these new observations, earlier tentative evidence for linkage of ADRP to the Rhesus locus on chromosome 1 will be re-evaluated. A locus for type II Usher syndrome (classical RP combined with congenital pedial deafness, and normal vestibular function) has now been established on the long arm of chromosome 1 (Kimberling et al. 1990). Type I Usher families, in which hearing loss is more profound and vestibular function absent, do not segregate with the same chromosome 1q markers, indicating the existence of another, as yet unlocated gene. In the X-linked form of the disease, two genes, XLRP2 and XLRP3, have been located on the proximal short arm of the X chromosome using a combination of physical and linkage mapping techniques, and there is some evidence to suggest a possible third locus more distally located.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Retinitis pigmentosa: genetic mapping in X-linked and autosomal forms of the disease. 220 66

In order to elucidate the genetic basis of autosomal dominant retinitis pigmentosa (adRP) in a large eight-generation family (UCLA-RP09) of British descent, we assessed linkage between the UCLA-RP09 adRP gene and numerous genetic loci, including eight adRP candidate genes, five anonymous adRP-linked DNA loci, and 20 phenotypic markers. Linkage to the UCLA-RP09 disease gene was excluded for all eight candidate genes analyzed, including rhodopsin (RP4) and peripherin/RDS (RP7), for the four adRP loci RP1, RP9, RP10 and RP11, as well as for 17 phenotypic markers. The anonymous DNA marker locus D17S938, linked to adRP locus RP13 on chromosome 17p13.1, yielded a suggestive but not statistically significant positive lod score. Linkage was confirmed between the UCLA-RP09 adRP gene and markers distal to D17S938 in the chromosomal region 17p13.3. A reanalysis of the original RP13 data from a South African adRP family of British descent, in conjunction with our UCLA-RP09 data, suggests that only one adRP locus exists on 17p but that it maps to a more telomeric position, at band 17p13.3, than previously reported. Confirmation of the involvement of RP13 in two presumably unrelated adRP families, both of British descent, suggests that this locus is a distinct adRP gene in a proportion of British, and possibly other, adRP families.
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PMID:Map refinement of locus RP13 to human chromosome 17p13.3 in a second family with autosomal dominant retinitis pigmentosa. 857 61