1 Montreal Children's Hospital, 2300 Tupper Street, Montreal, Quebec
Great significance is often attached to the detection of an abnormal accumulation of an amino acid in the body fluids of a patient, for this can be the manifestation of an amino-acidopathv. Screening programs designed to discover latent hereditary metabolic disease are frequently dependent on their ability to discriminate a single sample showing an abnormal concentration of a metabolite from the many thousands of normal samples. It is tacitly assumed in such circumstances that we know what is "normal."
To achieve an understanding of the normal distribution of amino acids in physiological fluids of man has required much time and great effort. An earlier Commentary1 described this well.