Pyruvate Dehydrogenase E1-Alpha Deficiency

A disorder that is the most frequent form of pyruvate dehydrogenase deficiency (PDHD) characterized by variable lactic acidosis, impaired psychomotor development, hypotonia and neurological dysfunction.

Epidemiology

Prevalence is unknown. Over 200 patients have been reported and while there are approximately equal numbers of males and females, male patients are generally more severely affected.

Clinical description

Patients present with a range of classic signs and symptoms of PDHD, including lactic acidosis, poor feeding, lethargy, tachypnea, developmental delay, growth retardation, poor acquisition or loss of motor milestones, hypotonia, seizures, ataxia and dystonia. Structural brain lesions including cortical atrophy, dilated ventricles, and incomplete corpus callosum, absence of the medullary pyramids and ectopia of the olivary nuclei are commonly observed, especially in female patients heterozygous for the disease-causing mutations that result in complete deficiency of E1-alpha subunit protein in cells expressing the gene mutation.

Etiology

The disease is caused by deficiency of the E1-alpha subunit of the PDH complex related to mutations in the PDHA1 gene (Xp22.1).

Genetic counseling

The pattern of inheritance is X-linked.