... development.Biotinidase deficiency (>1 in 75,000). An inherited disorder resulting in lack of the enzyme that recycles the vitamin biotin. May cause frequent infections, uncoordinated movement, hearing ... 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. ... illness. 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,...