PDP1 and Acidosis: Any impairment in pyruvate oxidation, whether it be due to a deficit in mitochondrial pyruvate import as in our study, decreased PDH activity [29] or defects in the TCA cycle or the respiratory chain [31], would be expected to result in increased reduction of pyruvate to lactic acid by the LDH, greater release of lactic acid into the extracellular medium and consequently to metabolic acidosis.