Increased GABA synthesis in skin fibroblasts of patients with Huntington's disease: a possible role of glutamic acid decarboxylase?

Activity of glutamic acid decarboxylase (GAD) was determined in extracts from cultured human skin fibroblasts of patients with Huntington's disease (HD) and compared to an age- and sex-matched control group. The fibroblasts were cultured up to eight passages. In patients suffering from HD a significant increased activity of GAD (～ 3–5 fold compared to age- and sex-matched controls) was found in passages 4–8. This may indicate a defect in the genetic expression of GAD concentration or regulation and/or may indicate that increased levels of glutamate may also be responsible for neuronal degeneration in HD.