Pyruvate Dehydrogenase E3 Deficiency

Pyruvate dehydrogenase E3 deficiency is a very rare subtype of pyruvate dehydrogenase deficiency (PDHD, see this term) characterized by either early-onset lactic acidosis and delayed development, later-onset neurological dysfunction or liver disease.

Epidemiology

Prevalence is unknown. About 20 cases have been reported to date.

Clinical description

The majority of patients have presented with neonatal lactic acidosis or with lactic acidosis, delayed development and hypotonia during infancy. A few patients have presented later in childhood with ataxia and dystonia with normal cognitive development. A separate group of patients, essentially all of Ashkenazi Jewish origin and many homozygous for a common G229C missense mutation, present with episodic vomiting, abdominal pain, encephalopathy and liver cell dysfunction. In some patients, there is evidence of branched chain alpha-ketoacid dehydrogenase deficiency, with elevated concentrations of the branched chain amino acids and their metabolites. However, clinical manifestations in most cases appear to be related to the pyruvate dehydrogenase deficiency.

Etiology

The disorder is caused by mutations in the DLD gene (7q31-q32).

Genetic counseling

The pattern of inheritance is autosomal recessive.