Fundus autofluorescence in carriers of X-linked recessive retinitis pigmentosa associated with mutations in RPGR, and correlation with electrophysiological and psychophysical data.

Abstract

To describe fundus autofluorescence (AF) in carriers of X-linked retinitis pigmentosa (XLRP) associated with mutations in RPGR (RP3), and to compare the findings on AF with ophthalmoscopy and with electrophysiological and psychophysical data. Eleven carriers from two families with XLRP and mutations in RPGR underwent clinical examination including fundus photography, AF, full-field electroretinography, Goldmann kinetic perimetry and two-colour threshold perimetry (2CT perimetry). An abnormal AF pattern was found in 9 of 11 carriers, with a radial pattern in 6 of 11. In 2CT perimetry patchy rod and cone sensitivity losses were seen in 7 of 8 carriers. Rods tended to be more affected than cones. The areas of sensitivity loss showed some correspondence with the abnormalities seen on AF. AF had a specific pattern in 9 of 11 carriers from two families with mutations in RPGR. The result was independent of the family investigated. The radial pattern may be explained by random X-inactivation early during embryogenesis subsequently preserved in all daughter cells and the centrifugal radial growth pattern of the developing neuroretina. AF may prove to be a rapid and easy clinical test to identify carriers of RP3.