GJB2 and maternally-inherited diabetes and deafness: At the same time, the absent of functional variants in GJB2, GJB3, GJB6, and TRMU genes suggested that these genes may not play putative roles in the phenotypic manifestation of MIDD, therefore, the combination of tRNATrp A5514G and tRNASer(AGY) C12237T mutations may be responsible for MIDD in this pedigree.