TBX1 and glutaryl-CoA dehydrogenase deficiency: We cannot at this point establish whether our data have a pathophysiological significance for glutaric aciduria type I. tGA accumulates in urine for excretion [65, 66], and excretion of this acid may become prominent, exceeding that of 3-hydroxyglutaric acid, during episodes of ketosis [4, 67].