PDK4 and hereditary elliptocytosis: Surprisingly, Pgc1α (peroxisome proliferator activated receptor gamma co-activator 1-alpha), the master regulator of mitochondrial biogenesis and function was only transiently induced by around 2 times at 12 months of age while Ppparα (peroxisome proliferator-activated receptor α) and Pdk4 (pyruvate dehydrogenase kinase 4) were increased at 12 and 24 months in HE mice compared to nTg mice.