In step 1, we performed PCR screening for 22 variants from 10 classical deafness genes (GJB2, SLC26A4, TMPRSS3, CDH23, OTOF, TMC1, ATP1A3, MPZL2, COCH, and 12S rRNA) and GJB2 single-gene sequencing (Figure S2).21 The gene discussed is MPZL2; the disease is deafness.