Amino Acid Metabolism And Urea Cycle Practice Test

A 2-year-old boy is brought to the pediatrician for developmental delay. The parents report he has had seizures and has a peculiar 'mousy' body odor. On examination, he has fair skin, blonde hair, and blue eyes, which is much lighter than his parents' complexion. A metabolic disorder is suspected.

A 5-day-old infant is evaluated for poor feeding, vomiting, and progressive lethargy. The mother notes that the infant's urine has a sweet smell, similar to burnt sugar. On examination, the infant displays alternating periods of hypertonia and hypotonia. Laboratory analysis is expected to show elevated plasma concentrations of specific amino acids.