... resulting in illness in first week of life. Severity varies, but death dur-ing first month and lifelong brain damage are common. Treatment includes low-protein diet, vitamin B12 injections, and ... Treatment includes a low-protein diet. Propionic acidemia (>1 in 75,000). Defect in processing four amino acids leading to ill-ness in newborns, including brain damage, coma, and death. ... special diet, continued indefinitely.Homocystinuria (<1 in 100,000). Lack of an enzyme that converts the amino acid homo-cysteine into cystathionine, needed for normal brain development....