PDHA1, also known as C54G1, is an alpha subunit of pyruvate dehydrogenase. Pyruvate dehydrogenase, together with dihydrolipoamide acetyltransferase and lipoamide dehydrogenase, composes the pyruvate dehydrogenase (PDH) complex. The PDH complex is a nuclear-encoded mitochondrial multienzyme complex that catalyzes the overall conversion of pyruvate to acetyl-CoA and CO(2), and provides the primary link between glycolysis and the tricarboxylic acid (TCA) cycle. PDHA1 plays a key role in the function of the PDH complex. Defects in PDHA1 can cause pyruvate dehydrogenase E1-alpha deficiency. Defects in PDHA1 also are the cause of X-linked Leigh syndrome (X-LS). X-LS is an early-onset progressive neurodegenerative disorder with a characteristic neuropathology consisting of focal, bilateral lesions in one or more areas of the central nervous system, including the brainstem, thalamus, basal ganglia, cerebellum, and spinal cord.