Mitchondrial cytopathies

visit http://www.mitomap.org/ for detailed information on cytopathies

Leigh disease (Complex 1>complex 2,3) aut rec
Succinate dehydrogenase gene (SDHB c and D) paraganglioma and pheochromocytoma, aut dom
polymerase gamma (POLG) mutations-- Alpers syndrome (hepatoencephalomyopathy), CPEO, spinocerebellar ataxia, sensory ataxia neuropathy with dysarthria and opthalmoplegia (SANDO),
ECGF1 (thymidine phosphorylase)- MNGIE

GI differential
liver involvement- Alpers syndrome
irritable bowel, intestinal pseudoobstruction--MELAS
severe GI dysfunction--MNGIE

Neuropathy-- MNGIE, SANDO

Historical points to ask about: deafness, short stature, early cardiac death in family, muscle discomfort or exercise intolerance, early onset DM.
Barth syndrome-- deafness and dystonia

Diagnostic tests
elevated lactate-- 60 percent sensitive, not completely specific
lactate/pyruvate ratio in CSF- may differentiate pyruvate dehydrogenase deficiency from primary mit. cytopathy
plasma amino acids-  elevated alanine may be seen
elevated CPK- may be seen in myopathy, not specific
alpha feto protein- may be seen in Alpers' syndrome early along with increased GGTPand others
thymidine levels-- high in MNGIE
urine organic acids-- high levels of ethylmalonic acid prompts ETHE1 gene for encephalopathy
     high 3 methyl glutaconic acid prompts look for tafazzin mutation for Barth syndrome
folate, B12, vitamin E- may be low in percentage coincidentally or secondarily

MRI- high T2 signal in putamen leading to striatal necrosis characterizes Leigh disease
occipital stroke-- consider MELAS