Disease Directory Choroideremia
Ophthalmological

Choroideremia

Also known as: CHM, tapetochoroidal dystrophy, REP1 deficiency

Prevalence

1 per 50,000–100,000

Onset

Childhood (night blindness); progressive through adulthood

Type

X-linked recessive

Gene

CHM

About Choroideremia

Choroideremia is an X-linked progressive retinal dystrophy caused by loss-of-function mutations in the CHM gene, which encodes Rab Escort Protein 1 (REP1), a protein required for normal vesicle trafficking in retinal cells. The disease is characterised by progressive degeneration of the choroid, retinal pigment epithelium, and photoreceptors beginning in the peripheral retina and advancing centripetally, ultimately leading to legal blindness in affected males, usually in mid-life. Female carriers are typically asymptomatic but exhibit patchy areas of chorioretinal atrophy and may have subtle visual symptoms.

Common Clinical Features

Night blindness beginning in childhood Progressive concentric peripheral visual field loss Patches of chorioretinal atrophy visible on fundus examination Reduced dark-adapted ERG responses Photophobia in some patients Central vision preserved until late in the disease course Legal blindness typically in the fourth to sixth decade Female carriers may have mild visual field defects

Clinical Trial Eligibility Tips

What to know before applying to Choroideremia trials.

Molecular confirmation of a CHM pathogenic variant is required; because this is a single-gene disease, genetic testing is straightforward and results are usually unambiguous.

Area of remaining intact retina (ellipsoid zone) measured by fundus autofluorescence and OCT is the key eligibility parameter in most gene therapy trials; preserve recent imaging records.

Affected males of a broad age range are typically eligible, but trials often exclude those with very limited residual central vision; enrol while central acuity is still measurable.

Patient Resources

Patient Organization

Choroideremia Research Foundation

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Natural History Registry

Choroideremia Research Foundation Patient Registry

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Orphanet

European reference resource for rare diseases (ORPHA:180)

View on Orphanet ↗

NORD

National Organization for Rare Disorders

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Find recruiting Choroideremia trials

Search 500,000+ studies from ClinicalTrials.gov, filtered for Choroideremia. Updated daily.

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