Choroideremia carriers maintain a normal electro-oculogram (EOG).
OBJECTIVE
To assess the functional integrity of the retinal pigment epithelium and outer retina in choroideremia (CHM) carriers with confirmed mutations in the REP-1 gene, by recording the EOG.


METHODS
The visual function of 17 choroideremia carriers ages 25-61 was assessed by determining their Snellen visual acuity and by recording the Arden ratio of the EOG. The 15 exons of the CHM gene were PCR-amplified from DNA from each of the carriers and their sequences were compared to the normal sequence to identify mutations.


RESULTS
The 17 CHM carriers had normal logMAR visual acuity (average of 0.07: Snellen equivalent of 20/25; with no acuities lower than 20/40). The average of the Arden ratio recorded from the 17 carriers was 2.71, which is not significantly different from the average value of 2.46 recorded in our lab. Fundus examination revealed mottled areas of chorioretinal degeneration consistent with the carrier status of CHM. Mutations in the CHM gene were identified in all CHM carriers by sequencing.


CONCLUSIONS
Whereas clinical observation suggests that progressive fundus changes are present in female carriers, these carriers do not show a change in the Arden ratio of the EOG over the ages studied (25-61 years).
Yau
Ryan J
RJ
Ocular Genetics Laboratory, University of Alberta, Edmonton, AB, Canada.
Sereda
Christina A
CA
McTaggart
Kerry E
KE
Sauvé
Yves
Y
MacDonald
Ian M
IM
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics; D000328:Adult; D015794:Choroideremia / Q000235:genetics / Q000503:physiopathology*; D004252:DNA Mutational Analysis; D004585:Electrooculography; D005260:Female; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010857:Pigment Epithelium of Eye / Q000502:physiology*; D016133:Polymerase Chain Reaction; D012160:Retina / Q000502:physiology*; D014792:Visual Acuity / Q000502:physiology; D020691:rab GTP-Binding Proteins / Q000235:genetics
D048868:Adaptor Proteins, Signal Transducing; C081787:CHM protein, human; D020691:rab GTP-Binding Proteins