FIGURE 1.

Molecular diagnostic flow of the present study: GJB2 single heterozygotes were analyzed using a stepwise and comprehensive molecular diagnostic protocol including massive parallel sequencing of 129 known deafness genes and Sanger sequencing of additional gap junction genes as well as screening of known GJB6 large deletions. Approximately half of GJB2 single heterozygotes were not DFNB1. Completely different causative genes or even digenic etiology involving the GJB2 mutation accounted for these non-DFNB1 subjects. DFNB1 = nonsyndromic hearing loss and deafness 1, GJB2 = gap junction protein beta 2, GJB6 = gap junction protein beta 6.