A C-terminal nonsense mutation links PTPRQ with autosomal-dominant hearing loss, DFNA73.

A C-terminal nonsense mutation links PTPRQ with autosomal-dominant hearing loss, DFNA73.

Genet Med. 2017 Oct 12;:

Authors: Eisenberger T, Di Donato N, Decker C, Delle Vedove A, Neuhaus C, Nürnberg G, Toliat M, Nürnberg P, Mürbe D, Bolz HJ

Abstract
PurposeHearing loss is genetically extremely heterogeneous, making it suitable for next-generation sequencing (NGS). We identified a four-generation family with nonsyndromic mild to severe hearing loss of the mid- to high frequencies and onset from early childhood to second decade in seven members.MethodsNGS of 66 deafness genes, Sanger sequencing, genome-wide linkage analysis, whole-exome sequencing (WES), semiquantitative reverse-transcriptase polymerase chain reaction.ResultsWe identified a heterozygous nonsense mutation, c.6881G>A (p.Trp2294*), in the last coding exon of PTPRQ. PTPRQ has been linked with recessive (DFNB84A), but not dominant deafness. NGS and Sanger sequencing of all exons (including alternatively spliced 5' and N-scan-predicted exons of a putative "extended" transcript) did not identify a second mutation. The highest logarithm of the odds score was in the PTPRQ-containing region on chromosome 12, and p.Trp2294* cosegregated with hearing loss. WES did not identify other cosegregating candidate variants from the mapped region. PTPRQ expression in patient fibroblasts indicated that the mutant allele escapes nonsense-mediated decay (NMD).ConclusionKnown PTPRQ mutations are recessive and do not affect the C-terminal exon. In contrast to recessive loss-of-function mutations, c.6881G>A transcripts may escape NMD. PTPRQTrp2294* protein would lack only six terminal residues and could exert a dominant-negative effect, a possible explanation for allelic deafness, DFNA73, clinically and genetically distinct from DFNB84A.GENETICS in MEDICINE advance online publication, 12 October 2017; doi:10.1038/gim.2017.155.

PMID: 29309402 [PubMed - as supplied by publisher]

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