THE MEANING OF MITOCHONDRIAL DISEASES IN DEFECTOLOGY

Mitochondrial diseases are a group of disorders characterized by morphological or functional defects of the mitochondria, the organelles producing most of our cellular energy. As the only extranuclear site carrying genetic information, the mitochondria add an important chapter in to the inheritance patterns of genetic disease. Because the mitochondria produce energy in all the tissues, symptoms resulting from mt DNA mutations may originate from any organ system, and the clinical spectrum of mitochondrial diseases has expanded to virtually all branches of medicine.Diagnosis of mitochondrial dysfunction may be difficult with currently available tools, however, measuring respiratory chain enzyme activities, mt DNA levels, and searching for mt DNA mutations and deletions are specific tests.Treatment of these disorders is currently empirical, involving agents that may improve the redox status of mitochondria, promote electron flow, or act as mitochondrial antioxidants.Limited data are available for genotype/phenotype correlation's in disorder caused by mt DNA mutations, therefore, prenatal diagnosis for mt DNA mutations has been hindered by an inability to predict accurately the clinical severity expected from a mutant load measured in fetal tissue