Hereditary deficiency of lactate dehydrogenase H-subunit.

We report herein the fifth family of hereditary deficiency of lactate dehydrogenase (LDH) H-subunit with an autosomal recessive inheritance including two cases of complete deficiency. Their LDH activities were low both in the serum and in the red blood cells (RBC). Electrophoretic analysis revealed that the patients with the complete deficiency had only the LDH5 isozyme.