• Disease Overview
  • Synonyms
  • Signs & Symptoms
  • Causes
  • Affected Populations
  • Disorders with Similar Symptoms
  • Diagnosis
  • Standard Therapies
  • Clinical Trials and Studies
  • References
  • Programs & Resources
  • Complete Report



Last updated: December 13, 2022
Years published: 1988, 1989, 1991, 1993, 2000, 2002, 2015, 2018, 2022


NORD gratefully acknowledges Lisa Vawter, PhD, Medical Writer and Ian M. MacDonald, MD, CM, Professor, Department of Ophthalmology and Visual Sciences, University of Alberta, for assistance in the preparation of this report.

Disease Overview

Choroideremia is a genetic disorder of sight that usually affects males. Female carriers may have mild symptoms without loss of vision. Major symptoms are difficulty seeing in the dark leading to progressive loss of peripheral vision, followed by tunnel vision. The rate and degree of vision loss differs among individuals. Night blindness, usually the first noticeable symptom, generally occurs during childhood.

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  • choroidal sclerosis
  • progressive choroidal atrophy
  • progressive tapetochoroidal dystrophy
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Signs & Symptoms

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. A layer of single pigmented cells is the layer outside of the retina. The choroid is the next layer located between the retina and the “white” section of the eye (the sclera); this layer contains small blood vessel).

Degeneration of the blood vessels of the choroid is followed by damage to the retina, which usually leads to loss of peripheral vision that can progress to eventual blindness. Central vision is usually preserved until late in life. The symptoms of choroideremia may vary greatly between affected individuals. Female carriers usually have very mild symptoms with night blindness or sensitivity to glare occurring late in life.

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Choroideremia can be caused by many different changes (called variants or mutations) 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. These disorders are caused by an abnormal gene on the X chromosome and manifest mostly in males. Females who have an altered gene on one of their X chromosomes are carriers for that disorder. Carrier females usually do not display symptoms, because females have two X chromosomes and only one carries the altered gene. Males have one X chromosome that is inherited from their mothers; if a male inherits an X chromosome that contains the altered gene, 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 has a child, he will pass the altered gene to all of 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 offspring.

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Affected populations

Choroideremia affects primarily males. Female carriers generally have few or no symptoms. However, a small number of females develop the disorder because of a genetic process that inactivates the normal gene and leaves only the dysfunctional 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.

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A doctor will perform tests that examine the patient’s visual field suspected of having choroideremia and will look inside the eye for degeneration of the retina. Genetic testing is available for some genetic variants that cause choroideremia.

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Standard Therapies

The symptoms of choroideremia can be treated but the disease itself cannot yet be cured. Organizations providing services to sight impaired people help patients and their families.

Genetic counseling is recommended for families affected by this disorder.

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Clinical Trials and Studies

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:http://www.centerwatch.com/

For information about clinical trials conducted in Europe, contact:https://www.clinicaltrialsregister.eu/

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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.

MacDonald IM. Lessons learned from research on choroideremia. Ophthalmic Genet. 2022 Jan 26:1-8. doi: 10.1080/13816810.2022.2025608. Epub ahead of print. PMID: 35080186.

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.

MacDonald IM, Hume S, Zhai Y, et al. Choroideremia. 2003 Feb 21 [Updated 2021 Mar 4]. In: Adam MP, Everman DB, Mirzaa GM, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2022. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1337/ Accessed Nov 22, 2022.

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: http://omim.org/entry/303100 Accessed Nov 22, 2022.

Orphanet. Choroideremia. Last update: December 2011. Available at http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=GB HYPERLINK “http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=GB&Expert=180″& HYPERLINK “http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=GB&Expert=180″Expert=180 Accessed Nov 22, 2022.

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Programs & Resources

RareCare® Assistance Programs

NORD strives to open new assistance programs as funding allows. If we don’t have a program for you now, please continue to check back with us.

Additional Assistance Programs

MedicAlert Assistance Program

NORD and MedicAlert Foundation have teamed up on a new program to provide protection to rare disease patients in emergency situations.

Learn more http://rarediseases.org/patient-assistance-programs/medicalert-assistance-program/

Rare Disease Educational Support 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.

Learn more http://rarediseases.org/patient-assistance-programs/rare-disease-educational-support/

Rare Caregiver Respite Program

This first-of-its-kind assistance program is designed for caregivers of a child or adult diagnosed with a rare disorder.

Learn more http://rarediseases.org/patient-assistance-programs/caregiver-respite/

Patient Organizations

IAMRARE® Patient Registry

Powered by NORD, the IAMRARE Registry Platform® is driving transformative change in the study of rare disease. With input from doctors, researchers, and the US Food & Drug Administration, NORD has created IAMRARE to facilitate patient-powered natural history studies to shape rare disease research and treatments. The ultimate goal of IAMRARE is to unite patients and research communities in the improvement of care and drug development.

Learn more >