Currently, the diagnostic yield from the first two steps – U-TOPTM HL genotyping kit and Sanger sequencing of GJB2, respectively – does not seem high, only reaching 12.6% including the homozygous p.V37I variants of GJB2. The U-TOPTM HL genotyping kit, initially designed to screen East Asian subjects with hearing loss, does not appear to be suitable for the Vietnamese population with hearing loss, where MYO15A and MYO7A were the most frequent causative genes. This evidence concerns the gene GJB2 and hearing loss disorder.