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An X-linked recessive, MIM 303100 hereditary retinal degeneration (other hereditary retinal degenerations include Refsum’s disease, gyrate atrophy and abetalipoproteinemia), characterised by progressive centripetal loss of visual fields and depth perception due to degeneration of the choroid and retina. It is caused by mutation of the CHM (formerly, REP-1) gene on chromosome Xq21 that encodes component A of the RAB geranylgeranyl transferase holoenzyme, which binds unprenylated Rab GTPases and then presents them to the catalytic Rab GGTase subunit for the geranylgeranyl transfer reaction.

Blindness is due to degeneration of choriocapillaris, retinal pigment epithelium and photoreceptors.


A rare genetic disorder featuring progressive degeneration of the CHOROID coat of the eye and leading to progressive visual loss and eventual blindness.
References in periodicals archive ?
Starting with the positive results from the recent choroideraemia trial, Professor MacLaren explained how gene therapy helped to stem the tide of retinal degeneration in a small cohort of patients with the condition, restoring a level of functional sight and enabling patients to see in dim light.