Résumé
We have shown that nasal ciliated epithelium, which can be easily biopsied under local anaesthetic, provides a good source of RNA transcripts from 8 of the 9 known genes which cause Usher syndrome, namely MYO7A, USH1C, CDH23, PCDH15, USH1G for Usher type 1 and USH2A, GPR98, WHRN for Usher type 2. Furthermore, the known or predicted effect on mRNA splicing of 8 variants was faithfully reproduced in the biopsied sample as measured by nested RT-PCR. These included changes at the canonical acceptor site, changes within the non-canonical acceptor site and both synonymous and non-synonymous amino acid changes. This shows that mRNA analysis by this method will help in assessing the pathogenic effect of variants, which is a major problem in the molecular diagnosis of Usher syndrome.