Clinical and pathological studies on two cases of mitochondrial enteromyopathy / 中华神经科杂志

ABSTRACT

Objective To report two cases of mitochondrial disease presenting with marked gastrointestinal symptoms and mild myopathy without involvement of central nerve system as to investigating the diagnostic rules of the disease Methods Case 1 is a 13 year old boy who had suffered from recurrent vomiting with mild diarrhea and fatigue for 7 years Physical examination showed mild weakness of both legs without ophthalmoplegia and cognitive defects Radiological examination revealed gastroptosis with excessive peristalsis of small intestine Case 2 is of a 6 year old boy who showed repeatedly the recurrent vomiting, intestinal pseudo obstruction and persistent muscle weakness over 1 year and 7 months There were no ophthalmoplegia. Barium clysis showed marked dilatation of colon. Cranial MRI in case 1 and CT in case 2 were unremarkable Muscle biopsies were performed in both cases and specimens were studied using routine histological and histochemical staining as well as using ultrastructural examination mtDNA analysis were performed in both cases Results Histological and enzym histochemical staining showed RRF and SDH positive fibers in both cases. Electron microscopic studies revealed mitochondrial proliferation with paracystalline inclusions in the muscle fibers with mild accumulation of lipid and glycogen. Genetic study revealed point mutation in mtDNA 3243A→G in case 1 and mtDNA3271T→C in case 2 Conclusion Mitochondrial cytopathy might be diagnosed upon the myopathological and genetic findings Different from MNGIE, Leigh disease and MELAS, the main clinical features were gastrointestinal symptoms, mild muscle weakness and no involvement of central nerve system in our patients, thus the mitochondrial entero myopathy, a new clinicopathological type of mitochondrial disorders, might be considered Since the muscle weakness was usually overlooked in patients with diarrhea, the mitochondrial cytopathy occurring should be considered with more attention as to elucidating the causes of children who have chronic gastrointestinal symptoms