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

Purpose: 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. Methods: 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). Results: 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. Conclusion: 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.