- Regional assignment of two genes of the human branched-chain alpha-keto acid dehydrogenase complex: the E1 beta gene (BCKDHB) to chromosome 6p21-22 and the E2 gene (DBT) to chromosome 1p31. Zneimer, S.M., Lau, K.S., Eddy, R.L., Shows, T.B., Chuang, J.L., Chuang, D.T., Cox, R.P. Genomics (1991)