Tricarboxylic Acid Cycle, Defect Of

Blass et al. (1972) studied cultured skin fibroblasts from the daughter of a couple related as second cousins once removed. An older sister had died in early childhood. The proband, aged 3 years, had severe generalized neurologic disease and persistent lactic acidosis. Radioactive citrate, palmitate, and pyruvate were oxidized at a rate less than one-third of normal. Deficiency was identified in the activity of the pyruvate dehydrogenase complex although not in the thiamine-dependent first enzyme of that complex. The patient was thought to have a partial genetic defect affecting the tricarboxylic acid cycle. For discussion of the enzyme complex involved, see Reed and Cox (1970).