TNNI2 and Down syndrome: The top-ten downregulated genes in Akita hearts by NGS analyses are helt BHLH transcription factor (HELT), olfactory receptor family member -51, subfamily E, member-2 (OR51E2), somatostatin receptor-3 (SSTR3), Usher syndrome-1C (USH1C), troponin-I type-2 (TNNI2), chloride channel voltage sensitive-1 (CLCN1), reticulon-4 receptor (RTN4R), solution carrier family-38, member-6 (SLC38A6), aldolase-B, fructose bisphosphate (ALDOB), 2’-5’-oligoadenylaste synthetase-2 (OAS2) (Fig 3B).