The mutation was identified as a 526 bp deletion encompassing the first putative methionine of the short C-terminal isoform and part of the long isoform. This creates a frameshift resulting in premature termination of the long isoform before the third PDZ domain. This deletion encompasses the majority of exons 6-10 of the gene, thus resulting in the ablation of both the long (WHRN-L) and the short (WHRN-S) isoforms.