Novel mutation in RP2 gene in two brothers with X-linked retinitis pigmentosa and mtDNA mutation of Leber hereditary optic neuropathy who showed marked differences in clinical severity

PURPOSE: To report the identification of a novel mutation of the RP2 gene i n two Japanese brothers with X-linked retinitis pigmentosa of a differing c linical severity. The mother was a carrier of both retinitis pigmentosa and optic atrophy. METHODS: The older brother had a severe form of retinitis pigmentosa associ ated 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 s uggests that the older brother may have developed Leber hereditary optic ne uropathy 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, (C) 2000 by Elsevier Science Inc. All rights reserved.