Disease Directory Achromatopsia
Ophthalmological

Achromatopsia

Also known as: Rod monochromacy, total color blindness, CNGA3/CNGB3 cone dystrophy

Prevalence

1 per 30,000

Onset

Congenital

Type

Autosomal recessive

Gene

CNGA3, CNGB3, GNAT2

About Achromatopsia

Achromatopsia is a congenital, stationary (non-progressive) retinal disorder caused by the complete absence of functional cone photoreceptors, resulting in total colour blindness, severely reduced visual acuity, extreme light sensitivity, and nystagmus from birth. The most common causative genes, CNGA3 and CNGB3, encode subunits of the cyclic nucleotide-gated channel essential for phototransduction in cone cells. Because the cone cells themselves are often structurally preserved despite being non-functional, gene therapy approaches aimed at restoring cone function have shown considerable promise in early-phase clinical trials.

Common Clinical Features

Complete absence of colour discrimination (total colour blindness) Best-corrected visual acuity of approximately 20/200 Severe photophobia and hemeralopia (day blindness) Pendular nystagmus from birth Preference for low-light environments Foveal hypoplasia on OCT Normal or near-normal rod-mediated ERG with absent cone ERG Reduced contrast sensitivity

Clinical Trial Eligibility Tips

What to know before applying to Achromatopsia trials.

Gene-specific eligibility is strict; CNGA3 and CNGB3 trials are separate programmes, so molecular confirmation of your specific pathogenic variant is mandatory.

Foveal cone structure assessed by adaptive optics or high-resolution OCT is used to determine whether sufficient residual cone cells remain to benefit from gene therapy; recent imaging is important.

Trials may cap enrolment by age, often preferring younger patients; contact trial coordinators early as paediatric cohorts can fill quickly.

Patient Resources

Patient Organization

Foundation Fighting Blindness

Visit website ↗

Natural History Registry

My Retina Tracker

Join registry ↗

Orphanet

European reference resource for rare diseases (ORPHA:49382)

View on Orphanet ↗

NORD

National Organization for Rare Disorders

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Find recruiting Achromatopsia trials

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

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