The absence of unique kainic acid-like molecules in urine, serum, and CSF from Huntington's disease patients.

By means of a sensitive competition assay, serum, urine, and CSF from patients with Huntington's disease (HD) and controls were tested for the presence of molecules capable of displacing radioactive kainic acid (KA) from rat brain receptors. No difference was found between HD and control samples. It is unlikely that systemic production of an endogenous toxin structurally related to KA occurs in HD.