choroideremia


choroideremia

 [ko-roi″der-e´me-ah] hereditary (X-linked) primary choroidal degeneration that, in males, eventually leads to blindness as degeneration of the retinal pigment epithelium progresses to complete atrophy; in females, it is nonprogressive and vision is usually normal.

cho·roi·der·e·mi·a

(kō-roy-der-ē'mē-ă), [MIM*303100] Progressive degeneration of the choroid in males, occasionally in females, beginning with peripheral pigmentary retinopathy, followed by atrophy of the retinal pigment epithelium and of the choriocapillaris, night blindness, progressive constriction of visual fields, and finally complete blindness; X-linked inheritance caused by mutation in the Rab escort protein-1 (REP1) gene on Xq; heterozygous females show a pigmentary retinopathy but without visual defect or peripheral progression. Synonym(s): progressive choroidal atrophy, progressive tapetochoroidal dystrophy [choroid + G. erēmia, absence]

choroideremia

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

choroideremia

Tapetochoroidal dystrophy A form of X-linked hereditary retinal degeneration–other hereditary retinal degenerations include Refsum's disease, gyrate atrophy and abetaipoproteinemia–characterized by a centripetal loss of visual fields due to a gene mutation in chromosome Xq21

cho·roi·der·e·mi·a

(kōr'oyd-ĕr-ē'mē-ă) Progressive degeneration of the choroid in males, occasionally in females, beginning with peripheral pigmentary retinopathy, followed by atrophy of the retinal pigment epithelium and of the choriocapillaris, night blindness, progressive constriction of visual fields, and finally complete blindness; X-linked inheritance; heterozygous females show a pigmentary retinopathy but without visual defect or peripheral progression.
Synonym(s): progressive choroidal atrophy, progressive tapetochoroidal dystrophy.[choroid + G.erēmia, absence]

choroideremia 

A bilateral, X-linked, recessive inherited degeneration of the choroid and retinal pigment epithelium characterized by night blindness (nyctalopia) which begins in early youth. Most males are myopic. The condition is mild and non-progressive in females. Both males and females display a salt and pepper appearance of the fundus, but in males it advances to complete atrophy and eventually blindness. Syn. progressive choroidal atrophy; progressive tapetochoroidal atrophy. See chromosome; inheritance.