MITOCHONDRIAL MYOPATHIES AND ENCEPHALOMYOPATHIES IN INFANCY AND CHILDHOOD A CLINICOPATHOLOGICAL STUDY

Abstract

Mitochondrial disorders usually present with a complex neurological picture so they are often overloo).;ed. So our nim is to study the heterogenous neurological presentation in patients with highly suspected mitochondrial disorders and diagnostic work up in the form of CPK, EMG, MRI brain. muscle biopsy for histochemistry & ultrastructure examination by E.M. Patients and Methods:

The study included 20 patients 7 females 35%, 13 males 65% with age range from 6 months- 13 : .:ars with a mean of 5 years presenting with clinical manifestation highly suggestive of mitochondrial disorder. They were subjected to history, clinical examination, investigation in the form of CPK. EMG, MRI. muscle biopsy for histochemical and EM examination. Results: This study included 20 patients 13 males, 7 females with age range from 5 months- 13

years with a mean of 5 years, 2 patients were sibling. They were classified into the following phenotypes, \lito. encephalomyopathies 5 cases (25%), Mito. Leucoencephalopathies 4 cases (20),, Mito. l\lyopathies (3 caeses) (15%), Leigh syndrome 2 cases (10%), familial dystonia 2 cases (10%). "'\ARP syndrome 2 cases (10%), MERRF I cases (5%). MELAS I case (5%). EMG results were 60% nonnal, 30% myopathic. 10% neuropathic. MRJ results were positive in 64,7% in the form offocal demyelination 17,6%, diffuse demyelination 17.6%, BG high signal intensties in 25.4%. muscle biopsy by histochemistry were diagnostic in 66,7% and by EM was diagnostic in 84.2%.

Conclusion

Clinical criteria raising the possibility of a mitochondrial disorders are: A myopathy ,,-ith nom1al, mild or moderately elevated CPK.A myopathy (hypotonia) associated with: Global developmental delay, Ataxia, deafness, increased liver enzymes, increased lactate, intractable seizures (brain &muscle disorders), nystagmus, blindness, hyperlactic acidemia Demyelinating brain lesion with severe hypotonia due to myopathy or peripheral neuropathy and in which the enzymatic studies for leukodystrophy are negative. A chronic progressive external ophthalmoplegia. Clinical picture suggestive of a specific syndrome such as MELAS or MERRF. Extrapyramidal manifestation± global developmental delay. Muscle biopsy testing by electron microscope & histochemistry is a diagnostic technique for mitochondrial disorder.