Decreased brain N-acetylaspartate in Huntington's disease.

The concentration of N-acetylaspartic acid (NAA) was measured in perchloric acid extracts of postmortem brain tissue obtained from patients with Huntington's disease and from control subjects. The material in the desalted extracts was resolved on an ion exclusion column and the content of NAA was determined by subsequent fluorometric quantitation of aspartate in hydrolyzates of the resolved NAA. The concentration of NAA in the putamen from patients with Huntington's disease was less than half that of controls (2.74 vs. 6.06 mumol/g wet weight). A smaller but significant reduction was also evident in samples of cerebral cortex from Brodmann area 10 (3.99 vs. 5.29 mumol/g), while the difference in concentrations in the cerebellum was not statistically significant. Though NAA could play a direct role in Huntington's disease, it seems more likely that the changes observed reflect illness or death of neurons, and that it may be feasible to monitor the course of Huntington's disease from NAA determinations. The same tissue extracts were also examined for the presence of D-isomers of amino acids. Only traces were found in NAA, aspartate, or glutamate.