MERRF syndrome

• DOI: 10.1016/j.ejpn.2017.04.1039
• Publication Date: 2017-06-14T21:33:01Z
• Authors: V. Duranovic; L. Lujic; J. Sekelj Fures; S. Pejic Rosko; M. Habek; J. Sertic; K. Vulin; I. Dakovic
• Keywords: Mitochondrial disease; MELAS syndrome; Mitochondrial encephalomyopathy; Lactic acidosis; Paroxysmal dyskinesia

Objective: MERRF (myoclonic epilepsy with ragged red fibers) is an inherited, progressive mitochondrial disease, caused by mutations in mitochondrial DNA. We present a case of 16- year-old girl with MERRF syndrome. Methods: Patient was admitted to our clinic because of progressive motor clumsiness, ataxia and dyskinesia. The symptoms began one year before admission. In the neurologic examination dominated difficulties in handwriting and coordination, intention tremor, ataxia, choreiform movements, dystonia (more on the upper extremities), orofacial dyskinesias, speech difficulties and mild cognitive deficit. Magnetic resonance images of the brain and spinal cord were normal. In the electroencephalogram photo-paroxysmal response was registered. Electroneurography showed axonal sensory polyneuropathy. Somatosensory evoked potentials were also abnormal. Tests of the autonomic nervous system showed severe adrenergic dysfunction (adrenergic score 3). Lactate and pyruvate levels were increased. Diagnostic workup excluded hereditary degenerative diseases with extrapyramidal symptomatology, some congenital ataxia, acquired causes of chorea and paraneoplastic syndromes. Laboratory results of serum copper, ceruloplasmin, vitamin B12, folic acid, biotinidase, vitamin E, sulfite urine test, amino acids, organic acids, VLCFA (very long chain fatty acid), carnitine and lysosomal enzymes were normal. A molecular-genetic analysis excluded Charcot-Marie-Tooth disease type 1A, hereditary neuropathy with liability to pressure palsies and MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke- like episodes). Results: A point mutation (m.8344A>G), pathognomonic for MERRF syndrome, was found. The same mutation was found in the mother, who has a mild expression of disease (arrhythmia) and younger sister, who is asymptomatic. The patient is being treated with L-carnitine and coenzyme Q10. She is involved in multidisciplinary follow-up. Conclusion: MERRF is a disorder that affects many parts of the body, particularly the muscles and nervous system. The features of MERRF vary widely among affected individuals. This case report is unique because autonomic dysfunction has not been described in patients with MERRF yet.