Hyperpipecolatemia: A new metabolic disorder associated with neuropathy and hepatomegaly: A case study.

DURING the course of the determination of serum amino acid concentrations in a group of children with mental retardation and be¬ haviour problems one child with a progressive generalized neurological disease was found to have a ninhydrin-positive compound not seen in sera of other patients. This was identified as pipecolic acid, a cyclic secondary amino acid that is involved in the metabolism of lysine,1' 23 and loading studies confirmed that there was a block in pipecolic acid metabolism. The pro¬ gressive downhill course of the illness was unaffected by dietary measures to reduce the in¬ take of pipecolic acid and its precursor, lysine, in spite of some reduction in serum pipecolate concentrations. This is a report of the clinical, biochemical and autopsy findings in what is believed to be the first such case studied.