Mitochondrial DNA mutations and heart disease (part 3). MITOCHONDRIAL MYOPATHY


An etiological relationship between myopathy and cardiomyopathy has been suspected based on some cardiomyopathic patients showing skeletal muscle disorders and other patients with myopathies showing cardiomyopathic changes. Mitochondrial myopathies, which comprise the Kearns-Sayre syndrome, including its incomplete type, ie, chronic progressive external ophthalmoplegia, myoclonic epilepsy with ragged red fibres (MERFF) and MELAS, are often associated with cardiac disorders. Kearns-Sayre syndrome is characterized by chronic progressive external ophthalmoplegia, heart block and pigmentary retinopathy. Its main cause is thought to be mitochondrial DNA deletions , although mitochondrial dysfunction induced by abnormal nuclear DNA may also be involved.The cardiac manifestations of this disease are arrhythmias, such as atrioventricular block, premature ventricular contractions, supraventricular or ventricular tachycardia, sinus dysrhythmia, ST and T changes, and cardiac dilation and failure. In many patients, a pacemaker should be implanted in order to prevent sudden death; some patients need a pacemaker at an advanced age. MELAS usually occurs in juveniles and is characterized symptomatically by headache, vomiting and stroke-like episodes such as hemiplegia . This disease is induced by point mutation within the mitochondrial tRNALeu^ gene either from A to G at position 324 or from thymine (T) to cytosine (C) at position 3271. Cardiac involvement results in cardiomyopathy. The mechanisms whereby point mutations in the tRNA gene induce pathological conditions are described elsewhere . Looking for a great online pharmacy you could trust and where you could find cipro antibiotic at best prices? You have one pharmacy like that already and can finally enjoy the best quality of service ever experienced.

Category: Cardiology

Tags: Cardiomyopathy, DNA mutation, Mitochondrial DNA

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