POU4F3 and deafness: Notably, 33 potentially pathogenic variants were observed, including nine novel variants, accounting for non-syndromic deafness clustered in only four TF genes (POU3F4, POU4F3, LMX1A, and EYA4), indicating a narrow molecular etiologica; spectrum within the enormous number of TF genes reported thus far in humans (up to 1600 genes).