Infrequency of urinary excretion of β-aminoisobutyric acid by healthy humans

Urinary β-aminoisobutyric acid (BAIB) levels were measured by modified ion-exchange chromatography. Daily BAIB levels are reported for a group of apparently healthy individuals, a subject with infective hepatitis and two human genetic variants who were high “excretors” of BAIB. The frequency of high “excretors” of BAIB was found using low-voltage paper electrophoresis. The frequency among 403 male European subjects was 5 (1.2%) and lower than previous estimates in the United Kingdom. The percentage recovery of fed BAIB suggests that Oriental “excretors” may have a different type of genetic lesion from non-Oriental “excretors”. The clinical usefulness of urinary BAIB assays and qualitative screening is reviewed.