Inherited metabolic disorders are single-gene genetic diseases associated with multiorgan damage. Some of these conditions increase the risk of stroke through a variety of mechanisms, and there is evidence that early recognition and initiation of appropriate treatment may improve prognosis. In this 2-part review we provide an update of the genetics, stroke pathophysiology, clinical manifestations, diagnosis, and treatment of metabolic disorders associated with stroke. In part 1, we concentrate on Fabry disease and mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes. In part 2 we will review homocystinuria, organic acidurias, and urea cycle disorders.