PCDH15 and hearing loss disorder: Pleiotropy associated with deafness-causing genes, where pathogenic variants in the same gene could cause either syndromic or nonsyndromic hearing loss, has been demonstrated for several other genes such as the genes involved in Usher syndrome (PCDH15; DFNB23/USH1F, USH1C; DFNB18A/USH1C, WHRN; DFNB31/USH2D, MYO7A; DFNB2/DFNA11/USH1B, CDH23; DFNB12/USH1D), WFS1 (DFNA6/14/38/Wolfram syndrome), TBC1D24 (DFNA65/DFNB86/DOORS syndrome), and COLL11A2 (DFNB53/DFNA13/STL3) (refs.1–3,5).