Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q00604 (X-linked)
 16,883 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The heterozygous states in X-linked ocular albinism, choroideremia and X-linked retinitis pigmentosa are described. Their fundus appearances differ, to a greater or lesser extent, from those of hemizygous (affected) males and a possible explanation for these differences is briefly discussed.
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PMID:X-linked retinal disorders and the Lyon hypothesis. 386 76

The luminance threshold for the detection of 25 Hz flicker was measured in nine patients with retinal disorders under stimulus conditions that have been shown previously to involve an interaction between rod and cone systems. The disorders studied included congenital stationary nightblindness, X-linked juvenile retinoschisis, hereditary dominant optic atrophy, optic atrophy found in association with neurofibromatosis, retinitis pigmentosa, choroideremia, and an acquired diffuse photoreceptor disorder, all of which involve pathologic changes that are presumed to occur primarily at specific levels of the retina. The results are consistent with a distal (outer) retinal locus for the rod-cone interaction.
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PMID:Rod-cone interaction in flicker perimetry: evidence for a distal retinal locus. 393 Jan 92

Choroideremia (McK 30310), an X-linked hereditary retinal dystrophy, causes nyctalopia, progressive visual field loss, and ultimately central blindness in affected males in early adulthood. We have used restriction fragment length polymorphisms from the X-chromosome to localize the region of the mutation for choroideremia in three families with this disorder. One polymorphic marker, DXYS1, located within Xq13-q21, shows no recombination with choroideremia at a LOD score of 5.78. Thus choroideremia maps within 9 centiMorgans of DXYS1 at 90% probability. Another marker, DXS11, located at Xq24-q26, shows no recombination with choroideremia but at a smaller LOD score of 1.54. These results suggest that the locus for choroideremia is distal to DXYS1 and between the two markers in the region Xq13-q24. This information may be useful for antenatal diagnosis, isolation of the mutant gene, and development of a rational therapy for the disorder.
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PMID:Mapping X-linked ophthalmic diseases. Provisional assignment of the locus for choroideremia to Xq13-q24. 403 75

Choroideremia, an X-linked form of retinal degeneration, results from defects in the Rab escort protein-1 (REP-1) gene. REP-1 and REP-2 assist in the attachment of geranylgeranyl groups to Rab GTPases, a modification essential for their action as molecular switches regulating intracellular vesicular transport. If Rabs that depend preferentially on REP-1 for prenylation exist, they will accumulate unprenylated in choroideremia cells. Using recombinant Rab geranylgeranyl transferase and REPs to label unprenylated cytosolic proteins, we identified one unprenylated protein in choroideremia lymphoblasts that was prenylated in vitro more efficiently by REP-1 than by REP-2. This protein was purified and identified as Ram (renamed Rab27), a previously cloned Rab of unknown function. Immunohistochemistry of rat retina showed that Ram/Rab27 is expressed in the pigment epithelium and choriocapillaris, the two retinal cell layers that degenerate earliest in choroideremia. These results raise the possibility that the retinal degeneration in choroideremia results from the deficient geranylgeranylation of Ram/Rab27 or a closely related protein.
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PMID:Deficient geranylgeranylation of Ram/Rab27 in choroideremia. 759 56

Parallel genetic analysis of animal and human genetic diseases can facilitate the identification and characterization of the causative gene defects. For example, canine X-linked severe combined immunodeficiency (SCID) is characterized by clinical, pathological, and immunological manifestations similar to the most common form of human SCID. To derive a canine syntenic map including genes that in humans are located in proximal Xq, near human X-linked SCID, poly(TG) polymorphisms were identified at the canine phosphoglycerate kinase (PGK) and choroideremia (CHM) loci. These plus a polymorphic poly(CAG) sequence in exon 1 of the canine androgen receptor gene (AR) were used to genotype members of the colony informative for X-linked SCID. No recombinations among SCIDX1, AR, PGK, or CHM were observed. Fluorescence in situ hybridization localized PGK and CHM to proximal Xq in the dog, in the same chromosomal location occupied by the human genes. Somatic cell hybrid analysis and methylation differences at AR demonstrated that female dogs carrying X-linked SCID have the same lymphocyte-limited skewed X-chromosome inactivation patterns as human carriers. These genetic and phenotypic findings provide evidence that mutations in the same gene, now identified as the gamma chain of the IL-2 receptor, cause canine and human X-linked SCID. This approach is an efficient method for comparative gene mapping and disease identification.
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PMID:Comparative mapping of canine and human proximal Xq and genetic analysis of canine X-linked severe combined immunodeficiency. 782 3

We have found that the microsatellite marker AFM207zg5 (DXS995) maps to all previously described deletions which are associated with X-linked mixed deafness (DFN3) with or without choroideremia and mental retardation. Employing this marker and pHU16 (DXS26) we have identified two partially overlapping yeast artificial chromosome clones which were used to construct a complete 850 kb cosmid contig. Cosmids from this contig have been tested by Southern blot analysis on DNA from 16 unrelated males with X-linked deafness. Two novel microdeletions were detected in patients which exhibit the characteristic DFN3 phenotype. Both deletions are completely contained within one of the known DFN3-deletions, but one of them does not overlap with two previously described deletions in patients with contiguous gene syndromes consisting of DFN3, choroideremia, and mental retardation. Assuming that only a single gene is involved, this suggests that the DFN3 gene spans a chromosomal region of at least 400 kb.
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PMID:X-linked mixed deafness (DFN3): cloning and characterization of the critical region allows the identification of novel microdeletions. 798 85

Familial exudative vitreoretinopathy (FEVR) is a congenital hereditary, bilateral eye disorder which affects both retina and the vitreous body. As a first step toward the identification of the gene responsible for the X-linked disorder, we report here the results of DNA analyses from the patients and their parents of two families having members affected with FEVR. The results indicate that loci MIC2 and choroideremia are unlikely to be associated with the disease. Similar results are obtained with anonymous probes DXS7 and DXYS1 and microsatellite markers DXS426, DXS453 and DXS454. No signs of microdeletion, substitution and rearrangements in these loci could be detected. These data suggest that the above loci are probably not involved in determining the FEVR pathology.
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PMID:Mapping studies of an X-linked familial exudative vitreoretinopathy. 809 90

Among the genetic diseases of vision, retinitis pigmentosa (alone or in combination with systemic afflictions like Usher syndrome, Kearns-Sayre syndrome) deserves special interest because it can be autosomal dominant, autosomal recessive, and X-linked. Leber's hereditary optic neuropathy, the first mitochondrial disease to be defined at the molecular level, manifests at mitochondrial DNA position 11778, but 10 other mutations have recently been found, all residing within mitochondrial DNA-encoded respiratory chain polypeptides. The analysis of Leber's optic neuropathy mutations has provided new important insight into the phenotypic expression of mitochondrial DNA mutations. Some rarer hereditary diseases of vision such as Cone dystrophy, dominant optic atrophy, Leber's congenital amaurosis, Stargardt maculopathy, and choroideremia are discussed.
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PMID:Genetic diseases of vision. 817 81

Rab geranylgeranyl transferase (GG transferase) is a two-component enzyme that attaches 20-carbon isoprenoid groups to cysteine residues in Rab proteins, a family of guanosine triphosphate-binding proteins that regulate vesicular traffic. The mutant gene in human choroideremia, an X-linked form of retinal degeneration, encodes a protein that resembles component A of rat Rab GG transferase. Lymphoblasts from choroideremia subjects showed a marked deficiency in the activity of component A, but not component B, of Rab GG transferase. The deficiency was more pronounced when the substrate was Rab3A, a synaptic vesicle protein, than it was when the substrate was Rab1A, a protein of the endoplasmic reticulum. The data imply the existence of multiple component A proteins, one of which is missing in choroideremia.
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PMID:Retinal degeneration in choroideremia: deficiency of rab geranylgeranyl transferase. 838 May 7

Mitochondrial DNA (mtDNA) was deleted in a patient with Kearns-Sayre syndrome (KSS) presenting with a choroideremia-like fundus picture instead of pigmentary retinopathy. No evidence for X-linked choroideremia was present, and because of the strong association between KSS and deleted mtDNA, we suggest that choroideremia is a phenocopy and can be part of KSS.
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PMID:Kearns-Sayre syndrome with a phenocopy of choroideremia instead of pigmentary retinopathy. 842 92


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