Lowered concentrations of branched-chain amino acids result in impaired growth and neurological problems: insights from a branched-chain alpha-keto acid dehydrogenase complex kinase-deficient mouse model.

Excess circulating levels of branched-chain amino acids (BCAA), as seen in maple syrup urine disease, result in severe neuropathology. A new mouse model, deficient in the kinase that controls BCAA catabolism, shows that very low circulating levels of BCAA are also associated with neuropathology, including the development of epileptic seizures. These mice clearly demonstrate the need to control essential amino acid levels within both upper and lower limits.