We describe the fortuitous discovery of a 44-year-oId man with a very
high hyperpipecolataemia (250 mu mol/L; normal <2.5). This patient has
none of the clinical features seen in peroxisomal diseases, he is a s
trictly normal intelligent adult. A stereochemical study of this pipec
olic acid was performed using D-amino acid oxidase, and identified it
as L-pipecolic acid. We suggest that isolated L-hyperpipecolataemia ma
y be a benign trait.