MDDS is diagnosed based on systemic symptoms presenting in infants, followed by a clinical examination and laboratory tests (for example, high lactate levels are common) medical imaging, and usually is finally confirmed and formally identified by genetic testing. Classification MDDS are a group of genetic disorders that share a common pathology — a lack of functioning<unk>  in mitochondria. There are generally four classes of MDDS: * a form that primarily affects muscle associated with mutations in the TK2 gene; * a form that primarily affects the brain and muscle associated with mutations in the genes SUCLA2, SUCLG1, or RRM2B; * a form that primarily affects the brain and the liver associated with mutations in DGUOK, MPV17, POLG, or TWNK (also called PEO1); and * a form that primarily affects the brain and the gastrointestinal tract associated with mutations in ECGF1 (also called TYMP).
Mitochondrial DNA depletion syndrome
Mitochondrial disease
Glutaminase deficiency
Pyruvate kinase deficiency
Pyruvate dehydrogenase deficiency
3-Methylcrotonyl-CoA carboxylase deficiency
Succinyl-CoA:3-oxoacid CoA transferase deficiency
Contiguous gene syndrome