Detection of localized retinal dysfunction in a choroideremia carrier

Purpose

To investigate severe unilateral vision loss in a choroideremia carrier.

Design

Case report.

Methods

Ocular examination, genetic testing, Humphrey visual fields, full-field and multifocal (mf) electroretinogram (ERG) tests were used to study a family with choroideremia.

Results

In a carrier with unilateral central vision loss, mfERG showed severely reduced amplitudes which correlated with a band of retinal pigment epithelial and choroidal atrophy in the macula, a dense central scotoma on Humphrey visual fields testing, and decreased ERG amplitudes.

Conclusions

Multifocal ERG may be a sensitive tool to measure functional abnormalities in choroideremia carriers. Mosaic inactivation of the normal gene may cause expression of the mutation with severe vision loss in choroideremia carriers.