To the Editor: Huntington's disease is a progressive degenerative condition affecting the nervous system and transmitted in an autosomal dominant manner. In the process of studying fibroblast metabolism in HD, we observed that these cells possessed a reduced growth potential. This preliminary communication (supported by a research grant [NB 06938] from the National Institutes of Health) is intended to document these observations.Fibroblast cultures were derived from skin biopsies taken from the mesial aspect of the mid-forearm; 28 cultures were obtained from 15 subjects with Huntington's disease. Repeat cultures on the same subjects were obtained after intervals that ranged from . . .