Variable proportions of mutant and normal transcripts have been reported to be tissue-dependent in atypical Usher syndrome type I patients [22], and thus the splicing of CDH23 is likely to show different regulation in whole blood and cochlea or retina, consequently explaining the milder phenotype (non-progressive RP and no vestibular dysfunction) of the proband, altogether leading to the reassignation of the clinical entity from USH2 into atypical USH1. This evidence concerns the gene CDH23 and retinitis pigmentosa 1.