Some individuals with BMKS do not have a compound heterozygous genotype, but are homozygous for a slightly different TXNL4A 34bp promoter deletion (chr18: g.77,748,604_77,748,637 (GRCh37, hg19), type 2 Δ34bp) [4,5,8]. Here, TXNL4A is linked to choanal atresia-hearing loss-cardiac defects-craniofacial dysmorphism syndrome.