Cerebrospinal fluid GABA and homocarnosine concentrations in patients with Friedreich's ataxia, Parkinson's disease, and Huntington's chorea.

ABSTRACT

Free and total gamma-aminobutyric acid (GABA) and homocarnosine concentrations were measured in the lumbar cerebrospinal fluid (CSF) of patients with Friedreich's ataxia, Huntington's chorea, and Parkinson's disease (with and without levodopa treatment), and compared with those determined in control subjects. Values found in Friedreich's ataxia or Parkinson's disease were not significantly different from those in controls. Unexpectedly, in Huntington patients, known to have a characteristic decrease in GABA concentrations in specific brain areas, CSF concentrations of total GABA and homocarnosine were significantly higher, whereas free GABA was not different from controls. These findings indicate that the measurement of CSF GABA and homocarnosine in patients with CNS degenerative diseases should be interpreted cautiously.