Bietti's crystalline dystrophy

Epidemiology

• rare disease
• more common in Asians

Pathology

• crystals in the cornea
• yellow, shiny deposits on the retina
• progressive atrophy of the retina, choriocapillaries & choroid
• progressive night blindness & visual field constriction
• crystals in lymphocytes seen by electron microscopy.
• composition of crsytals unkonwn
• crystals do not appear to harm the patient in any other way except to affect vision

Genetics

• autosomal recessive inheritance
• associated with defects in CYP4V2
• involved gene(s) localized to chromosome 4

Clinical manifestations

• progressive
• patients develop decreased vision, nyctalopia, & paracentral scotomata between the 2nd & 4th decade of life
• later, patients develop peripheral visual field loss & marked visual impairment, usually progressing to legal blindness by the 5th or 6th decade of life

Management

there is no treatment

More general terms

• eye disease (ophthalmopathy)
• developmental disorder

Additional terms

• Biett sign

Database

• OMIM: https://mirror.omim.org/entry/210370