have a maple syrup odor in cerumen; by 12-24 hours, elevated plasma concentrations of branched-chain amino acids (BCAAs) (leucine, isoleucine, and valine) and allo-isoleucine, as well as a generalized disturbance of plasma amino acid concentration ratios; by age two to three days, ketonuria, irritability, and poor feeding; by age four to five days, deepening encephalopathy manifesting as lethargy, intermittent apnea, opisthotonus, and stereotyped movements such as "fencing" and "bicycling." By age seven