choroideremia

Summary

Summary: An X chromosome-linked abnormality characterized by atrophy of the choroid and degeneration of the retinal pigment epithelium causing night blindness.

Top Publications

  1. Preising M, Ayuso C. Rab escort protein 1 (REP1) in intracellular traffic: a functional and pathophysiological overview. Ophthalmic Genet. 2004;25:101-10 pubmed
    ..REP1 null mutations underlie an X-linked retinal degeneration called choroideremia (CHM). This review summarizes the current biochemical and clinical knowledge on REP1 and CHM.
  2. Anand V, Barral D, Zeng Y, Brunsmann F, Maguire A, Seabra M, et al. Gene therapy for choroideremia: in vitro rescue mediated by recombinant adenovirus. Vision Res. 2003;43:919-26 pubmed
    b>Choroideremia (CHM) is an X-linked retinal degenerative disease resulting from a lack of functional Rab Escort Protein-1 (REP-1)...
  3. MacLaren R, Groppe M, Barnard A, Cottriall C, Tolmachova T, Seymour L, et al. Retinal gene therapy in patients with choroideremia: initial findings from a phase 1/2 clinical trial. Lancet. 2014;383:1129-37 pubmed publisher
    b>Choroideremia is an X-linked recessive disease that leads to blindness due to mutations in the CHM gene, which encodes the Rab escort protein 1 (REP1)...
  4. Preising M, Wegscheider E, Friedburg C, Poloschek C, Wabbels B, Lorenz B. Fundus autofluorescence in carriers of choroideremia and correlation with electrophysiologic and psychophysical data. Ophthalmology. 2009;116:1201-9.e1-2 pubmed publisher
    To describe fundus autofluorescence (FAF) in carriers of choroideremia (CHM), and to compare FAF findings with ophthalmoscopy and electrophysiologic and psychophysical data.
  5. Rak A, Pylypenko O, Niculae A, Pyatkov K, Goody R, Alexandrov K. Structure of the Rab7:REP-1 complex: insights into the mechanism of Rab prenylation and choroideremia disease. Cell. 2004;117:749-60 pubmed
    ..in members of this family, such as REP-1, lead to abnormalities, including progressive retinal degradation (choroideremia) in humans...
  6. O S, Kim S, Lee H. A case of choroideremia with recurrent anterior uveitis. Korean J Ophthalmol. 2003;17:55-62 pubmed
    b>Choroideremia is a rare hereditary disease with characteristic fundus that causes night blindness and peripheral visual field loss. The authors encounter choroideremia accompanied by recurrent uveitis...
  7. Fujimura K, Tanaka K, Nakano A, Toh e A. The Saccharomyces cerevisiae MSI4 gene encodes the yeast counterpart of component A of Rab geranylgeranyltransferase. J Biol Chem. 1994;269:9205-12 pubmed
    ..We propose that the MSI4 gene product is a yeast counterpart of component A of Rab geranylgeranyltransferase that is essential for Ypt1p to localize on membranes...
  8. Fodor E, Lee R, O Donnell J. Analysis of choroideraemia gene. Nature. 1991;351:614 pubmed
  9. Seabra M, Brown M, Slaughter C, Sudhof T, Goldstein J. Purification of component A of Rab geranylgeranyl transferase: possible identity with the choroideremia gene product. Cell. 1992;70:1049-57 pubmed
    ..Six peptides from rat component A show striking similarity to the product of the defective gene in choroideremia, an X-linked retinal degeneration disease. The choroideremia protein resembles Rab3A GDI, which binds Rab3A...

More Information

Publications65

  1. Genead M, McAnany J, Fishman G. Topical dorzolamide for treatment of cystoid macular edema in patients with choroideremia. Retina. 2012;32:826-33 pubmed publisher
    To determine the value of a topical carbonic anhydrase inhibitor on the macular thickness and function in choroideremia patients with cystoid macular edema.
  2. Cremers F, Sankila E, Brunsmann F, Jay M, Jay B, Wright A, et al. Deletions in patients with classical choroideremia vary in size from 45 kb to several megabases. Am J Hum Genet. 1990;47:622-8 pubmed
    Making use of the p1bD5 probe (DXS165), we have isolated several markers from the choroideremia locus by chromosomal jumping, preparative field-inversion gel electrophoresis, and cloning of a deletion junction fragment...
  3. Bonilha V, Trzupek K, Li Y, Francis P, Hollyfield J, Rayborn M, et al. Choroideremia: analysis of the retina from a female symptomatic carrier. Ophthalmic Genet. 2008;29:99-110 pubmed publisher
    To define the retinal pathology in a 91 year-old affected matriarch of a three-generation choroideremia family with multiple manifesting carriers.
  4. Syed R, Sundquist S, Ratnam K, Zayit Soudry S, Zhang Y, Crawford J, et al. High-resolution images of retinal structure in patients with choroideremia. Invest Ophthalmol Vis Sci. 2013;54:950-61 pubmed publisher
    To study retinal structure in choroideremia patients and carriers using high-resolution imaging techniques.
  5. Corbeel L, Freson K. Rab proteins and Rab-associated proteins: major actors in the mechanism of protein-trafficking disorders. Eur J Pediatr. 2008;167:723-9 pubmed publisher
    ..its associated protein is expressed, frequent features are hypopigmentation (Griscelli syndrome), eye defects (Choroideremia, Warburg Micro syndrome and Martsolf syndrome), disturbed immune function (Griscelli syndrome and Charcot-..
  6. Macdonald I, Russell L, Chan C. Choroideremia: new findings from ocular pathology and review of recent literature. Surv Ophthalmol. 2009;54:401-7 pubmed publisher
    Histopathology of young individuals affected by choroideremia is rarely available to allow correlation with the clinical presentation...
  7. van den Hurk J, Hendriks W, van de Pol D, Oerlemans F, Jaissle G, Rüther K, et al. Mouse choroideremia gene mutation causes photoreceptor cell degeneration and is not transmitted through the female germline. Hum Mol Genet. 1997;6:851-8 pubmed
    b>Choroideremia (CHM) is an X-linked progressive eye disorder which results from defects in the human Rab escort protein-1 (REP-1) gene. A gene targeting approach was used to disrupt the mouse chm/rep-1 gene...
  8. Sandberg M, Gaudio A. Reading speed of patients with advanced retinitis pigmentosa or choroideremia. Retina. 2006;26:80-8 pubmed
    ..To quantify, account for, and enhance the reading speed of patients with generalized retinal degeneration and small central visual fields...
  9. van Bokhoven H, van den Hurk J, Bogerd L, Philippe C, Gilgenkrantz S, de Jong P, et al. Cloning and characterization of the human choroideremia gene. Hum Mol Genet. 1994;3:1041-6 pubmed
    ..resulted in the identification of a gene which is disrupted by deletions in patients with the classic choroideremia (CHM) phenotype...
  10. Villaverde C, Trujillo Tiebas M, Garcia Hoyos M, Narvaiza R, Perez N, Garcia Sandoval B, et al. Novel human pathological mutations. Gene symbol: CHM. Disease: choroideraemia. Hum Genet. 2007;121:648 pubmed
  11. Macdonald I, Sereda C, McTaggart K, Mah D. Choroideremia gene testing. Expert Rev Mol Diagn. 2004;4:478-84 pubmed
    b>Choroideremia is a chorioretinal degeneration displaying X-linked recessive inheritance. In recent years, technological advances have increased the accessibility of genetic testing for mutations in the gene that lead to this disorder...
  12. Poloschek C, Kloeckener Gruissem B, Hansen L, Bach M, Berger W. Syndromic choroideremia: sublocalization of phenotypes associated with Martin-Probst deafness mental retardation syndrome. Invest Ophthalmol Vis Sci. 2008;49:4096-104 pubmed publisher
    To identify the mutation leading to syndromic choroideremia (CHM) in two families and to define fundus autofluorescence (FAF) in CHM carriers.
  13. Francis P, Fishman G, Trzupek K, Macdonald I, Stone E, Weleber R. Stop mutations in exon 6 of the choroideremia gene, CHM, associated with preservation of the electroretinogram. Arch Ophthalmol. 2005;123:1146-9 pubmed
  14. van den Hurk J, van de Pol D, Wissinger B, van Driel M, Hoefsloot L, de Wijs I, et al. Novel types of mutation in the choroideremia ( CHM) gene: a full-length L1 insertion and an intronic mutation activating a cryptic exon. Hum Genet. 2003;113:268-75 pubmed
    b>Choroideremia (CHM) is a progressive chorioretinal degeneration caused by mutations in the widely expressed CHM gene on chromosome Xq21...
  15. Yip S, Cheung T, Chu M, Cheung S, Leung K, Tsang K, et al. Novel truncating mutations of the CHM gene in Chinese patients with choroideremia. Mol Vis. 2007;13:2183-93 pubmed
    b>Choroideremia (CHM) is an X-linked retinal degenerative disorder caused by mutations in the CHM gene. The mutations result in malfunction of the Rab escort protein 1 (REP-1)...
  16. Coussa R, Kim J, Traboulsi E. Choroideremia: effect of age on visual acuity in patients and female carriers. Ophthalmic Genet. 2012;33:66-73 pubmed publisher
    The extent and time course of vision loss in Choroideremia (CHM) is still unclear...
  17. Alory C, Balch W. Organization of the Rab-GDI/CHM superfamily: the functional basis for choroideremia disease. Traffic. 2001;2:532-43 pubmed
    b>Choroideremia is an X-chromosome-linked disease that leads to the degeneration of the choriocapillaris, the retinal pigment epithelium and the photoreceptor layer in the eye...
  18. Syed N, Smith J, John S, Seabra M, Aguirre G, Milam A. Evaluation of retinal photoreceptors and pigment epithelium in a female carrier of choroideremia. Ophthalmology. 2001;108:711-20 pubmed
    To clarify the pathogenesis of choroideremia.
  19. Sergeev Y, Smaoui N, Sui R, Stiles D, Gordiyenko N, Strunnikova N, et al. The functional effect of pathogenic mutations in Rab escort protein 1. Mutat Res. 2009;665:44-50 pubmed publisher
    b>Choroideremia (CHM) is a chorioretinal degeneration with an X-linked pattern of inheritance. Affected males experience progressive atrophy of the choroid, retinal pigment epithelium and retina leading to eventual blindness...
  20. Alory C, Balch W. Molecular basis for Rab prenylation. J Cell Biol. 2000;150:89-103 pubmed
    ..REP1 in mammalian cells is the product of the choroideremia gene (CHM)...
  21. Renner A, Fiebig B, Cropp E, Weber B, Kellner U. Progression of retinal pigment epithelial alterations during long-term follow-up in female carriers of choroideremia and report of a novel CHM mutation. Arch Ophthalmol. 2009;127:907-12 pubmed publisher
    To report clinical and functional findings in 2 female carriers of choroideremia who were followed up for 11 and 17 years and who showed progression of fundus alterations; and to report a novel CHM mutation.
  22. Seabra M, Brown M, Goldstein J. Retinal degeneration in choroideremia: deficiency of rab geranylgeranyl transferase. Science. 1993;259:377-81 pubmed
    ..The mutant gene in human choroideremia, an X-linked form of retinal degeneration, encodes a protein that resembles component A of rat Rab GG ..
  23. Zhou Q, Liu L, Xu F, Li H, Sergeev Y, Dong F, et al. Genetic and phenotypic characteristics of three Mainland Chinese families with choroideremia. Mol Vis. 2012;18:309-16 pubmed
    To describe the phenotype and genotype of three Mainland Chinese families affected by choroideremia (CHM).
  24. Jiang Y, Ferro Novick S. Identification of yeast component A: reconstitution of the geranylgeranyltransferase that modifies Ypt1p and Sec4p. Proc Natl Acad Sci U S A. 1994;91:4377-81 pubmed
    ..Component A, encoded by the choroideremia gene in humans, is an escort protein that brings Rabs to component B, the catalytic alpha/beta heterodimer...
  25. Lazow M, Hood D, Ramachandran R, Burke T, Wang Y, Greenstein V, et al. Transition zones between healthy and diseased retina in choroideremia (CHM) and Stargardt disease (STGD) as compared to retinitis pigmentosa (RP). Invest Ophthalmol Vis Sci. 2011;52:9581-90 pubmed publisher
    To describe the structural changes across the transition zone (TZ) in choroideremia (CHM) and Stargardt disease (STGD) and to compare these to the TZ in retinitis pigmentosa (RP).
  26. Bowne S, Humphries M, Sullivan L, Kenna P, Tam L, Kiang A, et al. A dominant mutation in RPE65 identified by whole-exome sequencing causes retinitis pigmentosa with choroidal involvement. Eur J Hum Genet. 2011;19:1074-81 pubmed publisher
    ..was not present in Irish controls, but was found in a second Irish family provisionally diagnosed with choroideremia, bringing the combined maximum two-point LOD score to 5.3...
  27. Tolmachova T, Wavre Shapton S, Barnard A, MacLaren R, Futter C, Seabra M. Retinal pigment epithelium defects accelerate photoreceptor degeneration in cell type-specific knockout mouse models of choroideremia. Invest Ophthalmol Vis Sci. 2010;51:4913-20 pubmed publisher
    b>Choroideremia (CHM) is a progressive X-linked degeneration of three ocular layers (photoreceptors, retinal pigment epithelium, and choroid), with a complex and still largely unclear pathogenesis...
  28. Larijani B, Hume A, Tarafder A, Seabra M. Multiple factors contribute to inefficient prenylation of Rab27a in Rab prenylation diseases. J Biol Chem. 2003;278:46798-804 pubmed
    ..Two genetic diseases involve the Rab geranylgeranylation machinery: choroideremia, an X-linked retinal degeneration resulting from loss-of-function mutations in REP1, and gunmetal, a mouse ..
  29. van den Hurk J, Schwartz M, van Bokhoven H, van de Pol T, Bogerd L, Pinckers A, et al. Molecular basis of choroideremia (CHM): mutations involving the Rab escort protein-1 (REP-1) gene. Hum Mutat. 1997;9:110-7 pubmed
    b>Choroideremia (CHM) is an X-linked recessive eye disease that results from mutations involving the Rab escort protein-1 (REP-1) gene. In 18 patients deletions of different sizes have been found...
  30. Mura M, Sereda C, Jablonski M, Macdonald I, Iannaccone A. Clinical and functional findings in choroideremia due to complete deletion of the CHM gene. Arch Ophthalmol. 2007;125:1107-13 pubmed
    To report the clinical, functional, and in vivo microanatomic characteristics of a family with choroideremia with a deletion of the entire gene that encodes for the Rab escort protein 1 (CHM).
  31. van den Hurk J, van de Pol T, Molloy C, Brunsmann F, Rüther K, Zrenner E, et al. Detection and characterization of point mutations in the choroideremia candidate gene by PCR-SSCP analysis and direct DNA sequencing. Am J Hum Genet. 1992;50:1195-202 pubmed
    By making use of positional cloning strategies we recently isolated a candidate gene for choroideremia (CHM), which is transcribed in retina, choroid, and/or retinal pigment epithelium...
  32. Seabra M, Ho Y, Anant J. Deficient geranylgeranylation of Ram/Rab27 in choroideremia. J Biol Chem. 1995;270:24420-7 pubmed
    b>Choroideremia, an X-linked form of retinal degeneration, results from defects in the Rab escort protein-1 (REP-1) gene...
  33. Strunnikova N, Barb J, Sergeev Y, Thiagarajasubramanian A, Silvin C, Munson P, et al. Loss-of-function mutations in Rab escort protein 1 (REP-1) affect intracellular transport in fibroblasts and monocytes of choroideremia patients. PLoS ONE. 2009;4:e8402 pubmed publisher
    b>Choroideremia (CHM) is a progressive X-linked retinopathy caused by mutations in the CHM gene, which encodes Rab escort protein-1 (REP-1), an escort protein involved in the prenylation of Rabs...
  34. Cremers F, Armstrong S, Seabra M, Brown M, Goldstein J. REP-2, a Rab escort protein encoded by the choroideremia-like gene. J Biol Chem. 1994;269:2111-7 pubmed
    ..the first characterized REP, is produced by a gene on the X chromosome that is defective in patients with choroideremia, a form of retinal degeneration. Cremers et al. (Cremers, F.P.M., Molloy, C. M., van de Pol, D. J. R...
  35. Endo K, Yuzawa M, Ohba N. Choroideremia associated with subretinal neovascular membrane. Acta Ophthalmol Scand. 2000;78:483-6 pubmed
    To report two Japanese patients with choroideremia, one male and one heterozygous female, who developed subretinal neovascular membrane and/or subretinal fibrosis in the intermediate stage of the disease, and, in addition, to describe ..
  36. Hume A, Collinson L, Rapak A, Gomes A, Hopkins C, Seabra M. Rab27a regulates the peripheral distribution of melanosomes in melanocytes. J Cell Biol. 2001;152:795-808 pubmed
    ..report a possible function of Rab27a, a protein implicated in several diseases, including Griscelli syndrome, choroideremia, and the Hermansky-Pudlak syndrome mouse model, gunmetal...
  37. Tolmachova T, Tolmachov O, Barnard A, De Silva S, Lipinski D, Walker N, et al. Functional expression of Rab escort protein 1 following AAV2-mediated gene delivery in the retina of choroideremia mice and human cells ex vivo. J Mol Med (Berl). 2013;91:825-37 pubmed publisher
    b>Choroideremia (CHM) is an X-linked retinal degeneration of photoreceptors, the retinal pigment epithelium (RPE) and choroid caused by loss of function mutations in the CHM/REP1 gene that encodes Rab escort protein 1...
  38. Duncan J, Aleman T, Gardner L, De Castro E, Marks D, Emmons J, et al. Macular pigment and lutein supplementation in choroideremia. Exp Eye Res. 2002;74:371-81 pubmed
    b>Choroideremia is an incurable X-linked retinal degeneration caused by mutations in the gene encoding Rab escort protein-1...
  39. Iino Y, Fujimaki T, Fujiki K, Murakami A. A novel mutation (967-970+2)delAAAGGT in the choroideremia gene found in a Japanese family and related clinical findings. Jpn J Ophthalmol. 2008;52:289-297 pubmed publisher
    To investigate the choroideremia (CHM) gene of one affected male and one obligate carrier in a Japanese family with choroideremia, and to characterize the related clinical features.
  40. McTaggart K, Tran M, Mah D, Lai S, Nesslinger N, Macdonald I. Mutational analysis of patients with the diagnosis of choroideremia. Hum Mutat. 2002;20:189-96 pubmed
    All reported mutations in the choroideremia (CHM) gene result in the truncation or complete absence of Rab escort protein 1 (REP1). Molecular analysis was carried out on 57 families diagnosed with CHM...
  41. Tolmachova T, Anders R, Abrink M, Bugeon L, Dallman M, Futter C, et al. Independent degeneration of photoreceptors and retinal pigment epithelium in conditional knockout mouse models of choroideremia. J Clin Invest. 2006;116:386-94 pubmed
    b>Choroideremia (CHM) is an X-linked degeneration of the retinal pigment epithelium (RPE), photoreceptors, and choroid, caused by loss of function of the CHM/REP1 gene...
  42. Krock B, Bilotta J, Perkins B. Noncell-autonomous photoreceptor degeneration in a zebrafish model of choroideremia. Proc Natl Acad Sci U S A. 2007;104:4600-5 pubmed
    b>Choroideremia is an X-linked hereditary retinal degeneration resulting from mutations in the Rab escort protein-1 (REP1)...
  43. Chi J, Macdonald I, Hume S. Copy number variant analysis in CHM to detect duplications underlying choroideremia. Ophthalmic Genet. 2013;34:229-33 pubmed publisher
    To investigate the possibility of duplications or deletions within the CHM gene as a cause of choroideremia (CHM).
  44. Tolmachova T, Tolmachov O, Wavre Shapton S, Tracey White D, Futter C, Seabra M. CHM/REP1 cDNA delivery by lentiviral vectors provides functional expression of the transgene in the retinal pigment epithelium of choroideremia mice. J Gene Med. 2012;14:158-68 pubmed publisher
    b>Choroideremia (CHM) is a progressive X-linked degeneration of three ocular layers: photoreceptors, retinal pigment epithelium (RPE) and choroid, caused by the loss of Rab Escort Protein-1 (REP1)...
  45. Coussa R, Traboulsi E. Choroideremia: a review of general findings and pathogenesis. Ophthalmic Genet. 2012;33:57-65 pubmed publisher
    b>Choroideremia (CHM) is an X-linked retinal dystrophy belonging to the family of blinding disorders. It is characterized by progressive degeneration of the choriocapillaris, retinal pigment epithelium and photoreceptors...
  46. Keiser N, Tang W, Wei Z, Bennett J. Spatial and temporal expression patterns of the choroideremia gene in the mouse retina. Mol Vis. 2005;11:1052-60 pubmed
    b>Choroideremia (CHM), an X-linked retinal disease, is caused by mutations affecting the CHM gene. This gene encodes REP-1, which functions in the covalent modifications of proteins involved in vesicle trafficking...
  47. Thobani A, Anastasakis A, Fishman G. Microperimetry and OCT findings in female carriers of choroideremia. Ophthalmic Genet. 2010;31:235-9 pubmed publisher
    To evaluate structural retinal changes and macular function by a combined spectral domain optical coherence tomography/scanning laser ophthalmoscope (OCT/SLO) microperimetry device in choroideremia carriers.
  48. Robert L, S n chal A, Bocquet B, Herbin L, Chaudieu G, Kalatzis V, et al. Screening for a canine model of choroideremia exclusively identifies nonpathogenic CHM variants. Ophthalmic Res. 2011;45:155-63 pubmed publisher
    b>Choroideremia is an X-linked, progressive photoreceptor degeneration disorder due to mutations in CHM. In addition to an atrophy of the outer retina, affected individuals present with a characteristic atrophy of the choroid...
  49. Perez Cano H, Garnica Hayashi R, Zenteno J. CHM gene molecular analysis and X-chromosome inactivation pattern determination in two families with choroideremia. Am J Med Genet A. 2009;149A:2134-40 pubmed publisher
    b>Choroideremia is an X-linked recessive retinal dystrophy characterized by progressive loss of the photoreceptor, the retinal pigment epithelium, and the choriocapillaris layers which ultimately can result in blindness by the fifth decade ..
  50. Moosajee M, Tulloch M, Baron R, Gregory Evans C, Pereira Leal J, Seabra M. Single choroideremia gene in nonmammalian vertebrates explains early embryonic lethality of the zebrafish model of choroideremia. Invest Ophthalmol Vis Sci. 2009;50:3009-16 pubmed publisher
    Mutations of the CHM gene underlie the X-linked chorioretinal degeneration choroideremia (CHM). The affected gene product, Rab Escort Protein (REP)1, mediates the posttranslational prenyl modification of Rab GTPases...
  51. Jacobson S, Cideciyan A, Sumaroka A, Aleman T, Schwartz S, Windsor E, et al. Remodeling of the human retina in choroideremia: rab escort protein 1 (REP-1) mutations. Invest Ophthalmol Vis Sci. 2006;47:4113-20 pubmed
    To characterize in detail the disease expression in choroideremia (CHM), a blinding X-linked disease of the retina caused by loss-of-function mutations in Rab Escort Protein 1 (REP-1)...
  52. Cremers F, Molloy C, van de Pol D, van den Hurk J, Bach I, Geurts van Kessel A, et al. An autosomal homologue of the choroideremia gene colocalizes with the Usher syndrome type II locus on the distal part of chromosome 1q. Hum Mol Genet. 1992;1:71-5 pubmed
    Employing the mouse homologue of the human choroideremia cDNA as a probe, we have identified a homologous human gene...
  53. Rudolph G, Preising M, Kalpadakis P, Haritoglou C, Lang G, Lorenz B. Phenotypic variability in three carriers from a family with choroideremia and a frameshift mutation 1388delCCinsG in the REP-1 gene. Ophthalmic Genet. 2003;24:203-14 pubmed
    To perform genotype-phenotype correlations in a family with choroideremia.
  54. Roberts M, Fishman G, Roberts D, Heckenlively J, Weleber R, Anderson R, et al. Retrospective, longitudinal, and cross sectional study of visual acuity impairment in choroideraemia. Br J Ophthalmol. 2002;86:658-62 pubmed
    ..In order to determine the degree and rate of VA impairment associated with this disease, the central VA was analysed in a large group of patients with choroideraemia...
  55. Pereira Leal J, Hume A, Seabra M. Prenylation of Rab GTPases: molecular mechanisms and involvement in genetic disease. FEBS Lett. 2001;498:197-200 pubmed
    ..b>Choroideremia patients have loss of function mutations in REP1 and the murine Hermansky-Pudlak syndrome model gunmetal ..
  56. Sankila E, Tolvanen R, van den Hurk J, Cremers F, de la Chapelle A. Aberrant splicing of the CHM gene is a significant cause of choroideremia. Nat Genet. 1992;1:109-13 pubmed
    b>Choroideremia (CHM) is an X-linked progressive degeneration of the choroid and retina. 12% of unrelated male patients carry deletions of the partially cloned CHM gene...