 Pyruvate carboxylase also plays a role in the formation of the protective sheath that surrounds certain nerve cells (myelin) and the production of brain chemicals called neurotransmitters.Mutations in the "PC" gene reduce the amount of pyruvate carboxylase in cells or disrupt the enzyme's activity.The missing or altered enzyme cannot carry out its essential role in generating glucose, which impairs the body's ability to make energy in mitochondria.