Most BMKS patients identified thus far have a 34bp deletion (chr18: g.77,748,581_77,748,614del (GRCh37, hg19), type 1 Δ34bp) within the promoter region of TXNL4A on one allele combined with a loss-of-function variant on the other allele. This evidence concerns the gene TXNL4A and choanal atresia-hearing loss-cardiac defects-craniofacial dysmorphism syndrome.