Two novel genetic associations with sector retinitis pigmentosa: USH2A and PRPF31

Though both variants are previously reported, the phenotype in those reports was not consistent with sector RP. The current USH2A pedigree is the first reported with the c.13274C>T' variant homozygously, expressing a restricted, predominantly perivascular, sectoral RP. Non-syndromic USH2 genes have not previously been associated with sector RP. In the PRPF31 pedigree (c.351dup), the proband has restricted/sectoral disease but her daughter has classic pan-retinal RP. The cause of the attenuated phenotype and intrafamilial variability is unknown but could depend on several factors including occult modifier genes and environmental influences (e.g. light exposure to the inferior retina).