Clinical findings in a carrier of a new mutation in the choroideremia gene.
OBJECTIVE
To describe the clinical and molecular findings of a female carrier of a new mutation in the choroideremia (CHM) gene.


METHODS
Single interventional case report.


METHODS
A 27-year-old woman was seen with mild difficulties with dark adaptation and a history of a retinal degeneration in her father and choroideremia in 3 male paternal first cousins. Visual acuity measurements, peripheral and color vision tests, electroretinography (ERG), Goldmann visual fields, fluorescein angiogram, computed tomography scan, and DNA analysis were performed.


METHODS
(1) Visual fields, (2) fluorescein angiography, and (3) DNA analysis.


RESULTS
Visual acuity decreased from 20/30 to 10/200 in the right eye abruptly over 2 months, then remained stable over 2 years of follow-up and remained 20/25 in the left eye. Goldmann visual fields showed development of a central scotoma in the right eye concurrent with the rapid decline. A small amount of subretinal hemorrhage was visible on dilated fundus examination at that time, but definite leakage was not evident on fluorescein angiography; afterwards, a choroidal neovascular membrane (CNV) was suspected. The ERG was normal. DNA analysis revealed that the patient was heterozygous for a previously undescribed substitution mutation at the 3'-splice site of intron 6 of the CHM gene (850-1 G to C), confirmed by mRNA analysis with reverse transcriptase polymerase chain reaction.


CONCLUSIONS
Severe visual acuity loss rarely occurs in female carriers of choroideremia mutations. The diagnosis should be considered in patients with a suitable family history and fundus findings. Physicians should consider the possibility of CNV development in such patients, which may be a response to abnormal retinal pigment epithelium. Recognition of this new mutation may help identify patients who could benefit from current and future treatments to protect against vision loss.
Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, Canada.
Michael J
MJ
Potter
Edward
E
Wong
Shelagh M
SM
Szabo
Kerry E
KE
McTaggart
D048868:Adaptor Proteins, Signal Transducing; D000328:Adult; D019883:Alkyl and Aryl Transferases / Q000235:genetics*; D015794:Choroideremia / Q000175:diagnosis / Q000235:genetics*; D004252:DNA Mutational Analysis; D003623:Dark Adaptation; D004596:Electroretinography; D005260:Female; D005451:Fluorescein Angiography; D006579:Heterozygote; D006801:Humans; D009154:Mutation; D012333:RNA, Messenger / Q000032:analysis; D012162:Retinal Degeneration; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014792:Visual Acuity
D048868:Adaptor Proteins, Signal Transducing; C081787:CHM protein, human; D012333:RNA, Messenger; D019883:Alkyl and Aryl Transferases