Ophthalmological

Bietti Crystalline Dystrophy

Also known as BCD, Bietti crystalline corneoretinal dystrophy, CYP4V2 mutation

Bietti Crystalline Dystrophy is a rare progressive retinal degeneration caused by mutations in CYP4V2, a gene encoding a cytochrome P450 enzyme involved in fatty acid metabolism, leading to the pathological accumulation of lipid crystalline

ORPHA:41751 ↗Gene CYP4V2Prevalence Less than 1 per 100,000; higher in East Asian populationsOnset Second to third decadeAutosomal recessive

0

studies recruiting now

as of 7 Sept 2026

14

studies registered in total

as of 7 Sept 2026

0

countries with a recruiting site

as of 7 Sept 2026

None

recruiting study posted to date

among recruiting studies

Recruiting trials

No recruiting trial found right now.

14 studies are registered for Bietti Crystalline Dystrophy, but none was recruiting as of 7 Sept 2026. Here is what is still worth doing.

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About Bietti Crystalline Dystrophy

Bietti Crystalline Dystrophy is a rare progressive retinal degeneration caused by mutations in CYP4V2, a gene encoding a cytochrome P450 enzyme involved in fatty acid metabolism, leading to the pathological accumulation of lipid crystalline deposits in the cornea, retina, and circulating lymphocytes. The disease is notably more prevalent in individuals of East Asian descent and is characterised by glistening yellow-white crystals scattered across the posterior pole of the retina, progressive chorioretinal atrophy, and eventual severe visual impairment. Disease progression is typically slow but relentless, with most patients reaching legal blindness by the fifth or sixth decade.

Common clinical features

Glistening crystalline deposits in the posterior retina visible on fundus examinationProgressive chorioretinal atrophy beginning in the posterior poleNight blindness and dark adaptation difficultiesVisual field constriction beginning in the peripheryDecreased central visual acuity in advanced stagesCorneal limbal crystals detectable on slit-lamp examinationReduced ERG responses (both rod and cone affected)Legal blindness in the fifth to sixth decade

From Orphanet’s phenotype annotations (CC BY 4.0). Not a complete list.

Before you apply

Things trial teams commonly ask about for Bietti Crystalline Dystrophy. Not eligibility rules; those are set by each study.

  • Molecular confirmation of biallelic CYP4V2 pathogenic variants is necessary; the high prevalence of a specific splicing variant in East Asian patients means targeted testing is often efficient.
  • Fundus autofluorescence and OCT are used to measure areas of surviving RPE and photoreceptors, which serve as eligibility and outcome measures in emerging trials.
  • Given the slow progression, early enrolment in natural history studies can establish a baseline that strengthens eligibility for future interventional trials.

Related conditions

Information, not medical advice. Trial listings are shown as recorded on ClinicalTrials.gov; whether any study is right for you is a decision for you and your clinicians, and eligibility is decided by each research team. Disease information from Orphanet (CC BY 4.0).