GJB2 and autosomal recessive nonsyndromic hearing loss 1A: The identification of the first GJB2 mutations causing DFNB1 HI (Kelsell et al., 1997) was soon followed by screenings that revealed a high frequency of GJB2 mutations among subjects with NSHI (Denoyelle et al., 1997; Zelante et al., 1997).