Selective screening of mitochondrial dysfunction in a region with a high level of neurological diseases
Y Grechanina, O Grechanina 
Kharkiv Interregional Specialized Medical Genetic Centre – Centre of Rare (Orphan) Diseases, Kharkiv, Ukraine
Kharkiv Research Institute of Medical Genetic of Kharkiv National Medical University, Ukraine
Introduction: Mitochondrial dysfunction is the cause of many pathological disorders that are different their variety and complexity. Intensive study of the mitochondrial (mtDNA) polymorphisms made define it as typical pathological process, for which there is no nosology and etiological specificity. The frequency of mitochondrial dysfunction in population is 1:3000.
Purpose: Determine the frequency of polymorphisms of mitochondrial DNA and biochemical markers of disturbance in the Krebs cycle in patients with neurological pathology.
Results: Clinical and genetic characteristics of mtDNA polymorphisms (203 patients) involve disorders of nervous (82.16% of patients), muscle (43.24%), ophthalmic (62.16%), cardiovascular (35.14%), skeletal (38.0%) and digestive system (40.54%). 75 patients (36.5%) had characteristic clinical features of classic mitochondrial syndromes MERRF, MELAS, NARP, Leigh, Kearns-Sayre, Leber (сonfirmed by molecular diagnostics). In 91 patients (45.31%) we found elements of syntropy.
The more frequent of mtDNA polymorphisms in patient with neurological symptoms were  tRNA polymorphisms-lysine: 8697G/A; 8860G; 8701G/A; 8856G/A; 8860 (CRS); 8251G/A; 8472S/T; 8448T/C; 8994G/A; 8337T/C; 8794S/T; 8584G/A; 8701A/G and amino acid substitutions tRNA-lysine (syn, thr/ala, pro/leu, met/val, met/thr, his/tyr, ala/thr). The causes of encephalopathy were associated with polymorphisms tRNA-lysine and new mutations (leucine tRNA) (3624 A/G; 3594S/T, 3705G/A, 3505/G, 3552T/A). 
Conclusions: The findings suggest the need to assess the state of the mitochondrial genome and metabolites of the Krebs cycle in patients with various neurological diseases, as pathways to pathogenetic therapy.