POU3F4 and deafness: A second round of targeted NGS on subject IV-5 in this family identified a hemizygous c.706G>A (p. Glu236Lys) variant in the X-chromosome gene POU3F4 (NM_000307.5), a causative gene for X-linked nonsyndromic deafness DFNX2. The c.706G>A (p. Glu236Lys) variant segregated with the deafness in the five aforementioned male family members, but it was not detected in any other family members (Figures 3(a) and 3(b)).