BCKDK and autism: BCAA supplementation in the brain has been found to improve neuronal function and the autism-linked phenotypes of mice or patients carrying mutations in Branched-chain ketoacid dehydrogenase kinase (BCKDK), a gene essential for catabolism of BCAA, and in Solute carrier transporter 7a5 (SLC7A5), a large neutral amino acid transporter essential for maintaining normal levels of BCAA in the brain [11,32,33].