Purpose: To report the identification of a novel mutation of the RP2 gene in two Japanese brothers with X-linked retinitis pigmentosa of a differing clinical severity. The mother was a carrier of both retinitis pigmentosa and optic atrophy.
Methods: The older brother had a severe form of retinitis pigmentosa associated with macular degeneration and total optic atrophy, whereas the younger brother presented typical X-linked retinitis pigmentosa.
Results: Each patient exhibited a novel 2-bp insertion at codon 278 in exon 3 of the RP2 gene as well as a 11778 mutation in mitochondrial DNA. This suggests that the older brother may have developed Leber hereditary optic neuropathy as well as retinitis pigmentosa.
Conclusion: Molecular testing confirmed the clinical diagnosis in each case. However, such testing did not explain the differences in the severity of the ophthalmoscopic findings between the two brothers.