Pyruvate dehydrogenase-e1α deficiency presenting as recurrent demyelination: an unusual presentation and a novel mutation.

The nucleus-encoded mitochondrial pyruvate dehydrogenase enzyme complex plays key roles in cellular energy metabolism and acid-base equilibrium. Pyruvate dehydrogenase complex deficiency is due to loss-of-function mutation in one of the five component enzymes, most commonly E1α-subunit. The common clinical presentation ranges from fatal infantile lactic acidosis in newborns to chronic neurological dysfunction. We describe here an unusual presentation of E1α-subunit deficiency presenting as recurrent demyelination, Guillain-Barré syndrome-like demyelinating polyneuropathy at the onset, and ophthalmoplegia in a young infant. The clinical phenotype of the mutation in the patient was unique as compared to the previous reported cases of pyruvate dehydrogenase deficiency. The mother was found to be a mosaic carrier of the mutation. This phenotypic variability of pyruvate dehydrogenase complex deficiency and early suspicion of its unusual neurological manifestations is highlighted. Thiamine and ketogenic diet can be helpful.