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Last updated: 4/23/2025
Years published: 1988, 1989, 1991, 1993, 2000, 2002, 2015, 2018, 2022, 2025
NORD gratefully acknowledges Lisa Vawter, PhD, Medical Writer and Ian M. MacDonald, MD, CM, Professor Emeritus in the Department of Ophthalmology and Visual Sciences, University of Alberta, for assistance in the preparation of this report.
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Choroideremia is a vision disorder characterized by difficulty seeing in the dark in childhood followed by progressive loss of peripheral vision resulting in tunnel vision later in life. The degree of vision loss may differ among individuals in the same family but is usually similar. Choroideremia is an X-linked genetic disorder that affects males and occasionally female carriers. Female carriers generally have milder symptoms than males.
Choroideremia is characterized by extensive loss of all retinal layers in the eyes. This disorder usually begins during childhood with wasting (atrophy) of the pigmented retinal epithelium, retina and choroid. The retina is the light sensitive, most internal layer, consisting of many nerve containing layers. There is a single layer of pigmented cells underneath the retina. The choroid is located between the retinal pigment epithelium and the “white” section of the eye (the sclera); this layer contains small blood vessels.
Degeneration of the retinal pigment epithelium results in secondary degeneration of the blood vessels of the choroid and the photoreceptors of the retina. These changes lead to loss of peripheral vision and can progress to eventual legal blindness. Central vision is usually preserved until late in life. The symptoms of choroideremia may vary between affected individuals. Female carriers usually have very mild symptoms with night blindness or sensitivity to glare late in life.
Choroideremia can be caused by many different changes (variants) in the CHM gene. The CHM gene encodes REP1 (RAB escort protein 1), a protein that takes part in targeting vesicles (small sacs of substances) into, out of and within cells.
Choroideremia is an X-linked recessive genetic condition. X-linked genetic disorders are conditions caused by a disease-causing gene variant on the X chromosome and mostly affect males. Females who have a disease-causing gene variant on one of their X chromosomes are carriers for that disorder. Carrier females usually do not have symptoms because females have two X chromosomes and only one carries the gene variant. Males have one X chromosome that is inherited from their mother and if a male inherits an X chromosome that contains a disease-causing gene variant, he will develop the disease.
Female carriers of an X-linked disorder have a 25% chance with each pregnancy to have a carrier daughter like themselves, a 25% chance to have a non-carrier daughter, a 25% chance to have a son affected with the disease and a 25% chance to have an unaffected son.
If a male with an X-linked disorder can reproduce, he will pass the gene variant to all his daughters who will be carriers. A male cannot pass an X-linked gene to his sons because males always pass their Y chromosome instead of their X chromosome to male children.
Choroideremia primarily affects males. Female carriers of a CHM gene variant generally have few or no symptoms. However, a small number of carrier females develop the disorder because of a genetic process that inactivates the normal copy of the CHM gene and leaves only the variant copy of the gene active. In the Salla area of northern Finland, an unusually high number of people have been diagnosed with choroideremia; approximately one in forty persons.
A doctor will perform tests to examine the visual field in a person suspected of having choroideremia and will look inside the eye for degeneration of the retina. Genetic testing is available for some gene variants that cause choroideremia.
The symptoms of choroideremia can be treated but the disease itself cannot yet be cured. Organizations listed below provide services for people with vision impairment and their families.
Genetic counseling is recommended for families affected by this disorder.
Information on current clinical trials is posted on the Internet at https://clinicaltrials.gov/ All studies receiving U.S. Government funding, and some supported by private industry, are posted on this government web site.
For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:
Tollfree: (800) 411-1222
TTY: (866) 411-1010
Email: [email protected]
Some current clinical trials also are posted on the following page on the NORD website: https://rarediseases.org/living-with-a-rare-disease/find-clinical-trials/
For information about clinical trials sponsored by private sources, contact: https://www.centerwatch.com/
For information about clinical trials conducted in Europe, contact: https://www.clinicaltrialsregister.eu/
REVIEW ARTICLES
Coussa RG, Traboulsi EI. Choroideremia: a review of general findings and pathogenesis. Ophthalm Genet 2012;33(2):57 65.
Mitra S, Cheng KW, Mills GB. Rab GTPases implicated in inherited and acquired disorders. Seminars Cell Develop Biol. 2011;22(1):57 68.
Pereira Leal JB, Hume AN, Seabra MC. Prenylation of Rab GTPases: molecular mechanisms and involvement in genetic disease. FEBS Lett 2001;498:197 200.
JOURNAL ARTICLES
MacDonald IM. Lessons learned from research on choroideremia. Ophthalmic Genet. Published online January 26, 2022. doi:10.1080/13816810.2022.2025608
MacLaren RE, Groppe M, Barnard AR, Cottriall CL, 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(9923):1129 37.
Köhnke M, Delon C, Hastie ML, Nguyen UTT, Wu Y W, Waldmann H, et al. Rab GTPase prenylation hierarchy and its potential role in choroideremia disease. PLoS One 2013;8(12):e81758.
Coussa RG, Kim J, Traboulsi E. Choroideremia: effect of age on visual acutity in patients and female carriers. Ophthmal Genet. 2012;33(2)66 73.
Lazow MA, Hood DC, Ramachandran R, Burke TR, Wang Y-Z, Greenstein VC, 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(13):9581-90.
MacDonald IM, Russell L, Chan C-C. Choroideremia: new findings from ocular pathology and review of recent literature. Surv Ophthalmol. 2009;54(3):401 407.
Tolmachova T, Anders R, Abrink M, Bugeon L, Dallman MJ, Ramalho JS et al. Independent degeneration of photoreceptors and retinal pigment epithelium in conditional knockout mouse models of choroideremia. J Clin Invest 2006;116:386–94.
Roberts MF, Fishman GA, Roberts DK, Heckenlively JR, Weleber RG, Anderson RJ, et al. Retrospective, longitudinal, and cross sectional study of visual acuity impairment in choroideraemia. Br J Ophthalmol 2002;86(6):658 62.
Seabra, M. C., Brown, M. S., Goldstein, J. L. Retinal degeneration in choroideremia: deficiency of Rab geranylgeranyl transferase. Science.1993;259:377 381.
INTERNET
MacDonald IM, Hume S, Zhai Y, et al. Choroideremia. 2003 Feb 21 [Updated 2021 Mar 4]. In: Adam MP, Feldman J, Mirzaa GM, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2025. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1337/ Accessed April 9, 2025.
McKusick VA., ed. Online Mendelian Inheritance in Man (OMIM). Baltimore. MD: The Johns Hopkins University; Entry No: 303100; Last Update:08/02/2019. Available at: https://omim.org/entry/303100 Accessed April 9, 2025.
Orphanet. Choroideremia. Last update: December 2011. Available at https://www.orpha.net/en/disease/detail/180 Accessed April 9, 2025.
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Learn more https://rarediseases.org/patient-assistance-programs/medicalert-assistance-program/Ensuring that patients and caregivers are armed with the tools they need to live their best lives while managing their rare condition is a vital part of NORD’s mission.
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Learn more https://rarediseases.org/patient-assistance-programs/caregiver-respite/The information provided on this page is for informational purposes only. The National Organization for Rare Disorders (NORD) does not endorse the information presented. The content has been gathered in partnership with the MONDO Disease Ontology. Please consult with a healthcare professional for medical advice and treatment.
The Genetic and Rare Diseases Information Center (GARD) has information and resources for patients, caregivers, and families that may be helpful before and after diagnosis of this condition. GARD is a program of the National Center for Advancing Translational Sciences (NCATS), part of the National Institutes of Health (NIH).
View reportOrphanet has a summary about this condition that may include information on the diagnosis, care, and treatment as well as other resources. Some of the information and resources are available in languages other than English. The summary may include medical terms, so we encourage you to share and discuss this information with your doctor. Orphanet is the French National Institute for Health and Medical Research and the Health Programme of the European Union.
View reportOnline Mendelian Inheritance In Man (OMIM) has a summary of published research about this condition and includes references from the medical literature. The summary contains medical and scientific terms, so we encourage you to share and discuss this information with your doctor. OMIM is authored and edited at the McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine.
View report