Stroke, that is one of the leading causes of death and disability in the world, is a multifactorial disease. It develops due to interaction of environmental factors and genetic predisposition, which structure and mechanisms are intensively studied. The most common type of stroke is the ischemic stroke. One of the new approaches in the study of stroke pathogenesis is researching microRNAs expression profiles. MicroRNAs are short noncoding RNAs that play an important role in the regulation of gene expression at the transcriptional and post-transcriptional levels. This review shows the significant role of microRNAs in stroke's etiology, pathogenesis, diagnostics and treatment. In stroke etiology, microRNAs, changing their expression profile, modulate the pathogenic mechanisms of atherosclerosis, hyperlipidemia, arterial hypertension, diabetes and plaque rupture. MicroRNAs can modify clinical aspects and clinical outcome by the influence on basic pathogenic mechanisms of ischemic brain damage (apoptosis, inflammation, brain edema). MicroRNAs may serve as biomarkers of stroke allowing to determine the type of stroke or the severity of brain damage, and they also could be used in the stroke treatment.

We analyzed the results of prenatal screening in women achieved pregnancy through IVF. There were examined 366 pregnant women: 93 twins (one of them monochorionic), 1 triplet and 262 singleton pregnancies. Integrated risk assessment was based on ultrasound and biochemical markers and 1% of threshold the high risk group consisted of 12 fetuses (2.5%). Invasive diagnostic procedure was performed in 7 pregnancies, 4 cases with chromosomal abnormalities were found, including 3 case of trisomy 21, and 1 case of trisomy 18. The total frequency of chromosomal abnormalities was 1 of 91 (1,08%) cases, andtrisomy21 —1 of 114cases. The integrated risk assessment of chromosomal abnormalities in IVF pregnancies has high efficacy and sensitivity. The median value definition for the biochemical indicators and a taking into account population and reproductive technology-related peculiarity are desirable to decrease the number of false-positive results.

On the basis of register of neuromuscular diseases in the Dagestan Republic («Neuroregister Dagestan») the prevalence of progressive muscular dystrophy Duchenne/Becker (PMD D/B) was estimated. Population of 10 towns and 41 districts were surveyed. The average prevalence of PMD D/B was 4.52 / 100,000 men. Accumulation defined for Gergebilsky (39.61/100,000) and Laksky (33.43 /100,000) districts. Analysis of differences in the prevalence of PMD D/B between ethnic groups of Dagestan Republic showed that the most frequently PMD D/B recorded among Kumyks (1:6977) and Rutuls (1:4129).

The paper presents the results of epidemiological studies of rare congenital malformation — esophageal atresia (EA). Data derived from birth defects monitoring during 2000—2012 in 30 regions of the Russian Federation. The total prevalence of AP for the entire observation period was 1.96 (95% C11.87—2.06) per 10 000 births or 1 case per 5099 births. The EA prevalence during the entire observation period remained stable. EA with tracheoesophageal fistula (TEF) represents 57.3% of the cases. In 68.2% of cases EA was isolated anomaly and associated malformations were present in 31.8%. Relative risk for EA was higher for the older maternal age group (RR is 1.51, 95% CI 1.25—1.84); for male (RR 1.22, 95% CI 1.08-to 1.38) and for infants with a birth weight less than 3,000 g (RR 4.82, 95% CI 4.24-5.48).

Analysis of DNA samples from buccal epithelium of Abkhazian residents was submitted for APOE polymorphism. The material was collected in 2013 and it was grouped according to the genetic research into two samples: a) persons of oldest age group (from 75 to 101 year); b) a control group of an average age cohort persons (from 16 to 33 years). APOE polymorphism (OMIM +107241) associated with effect of life duration in other world populations were investigated. Among many diseases which are associated with certain APOE genotypes, carriers of APOE*4 allele are characterized by the increased risk of development of cardiovascular pathology. APOE*3 and APOE*4 allele frequencies demonstrated for Abkhazian long-livers were 0,9359 and 0,0128 respectively, while in control group these frequencies were 0,8315 and 0,0815 respectively. Distinctions between the compared cohorts concerning alleles APOE*3 and APOE*4 frequencies were significant (at x² > 10 and 8 respectively and P<0,05). Distinctions between the compared groups concerning genotype frequencies were also significant (x² = 10,072; d.f. = 5; P < 0,05). Frequencies of APOE*2 allele were statistically similar for both samples. So the ApOe 4-4 genotype and APOE*4 allele seem to be unfavorable for the oldest age group. On the contrary, APOE*3 allelomorph and genotypes connected with APOE*3 are favorable factors. Our results confirmed previous observation that frequency of the «wild» genetic factors increases to the maximum in the oldest age group.

By use of the unbiased differential DNA methylation screening we have identified 16 novel genome loci aberrantly methylated in pediatric acute myeloid leukemia. Almost all of them belong to promoter CpG islands except one corresponding to the intergenic CpG island on the chromosome 7p21.1. Two of the genes shown to be abnormally methylated in our study encode proteins involved in the epigenetic regulation of gene expression, namely, RXRA, involved in the posttranslational hystone modifications, and KHSRP/KSRP, that binds to adenine/uracil rich RNA sequences and regulates posttranscriptional RNA stability. We suggest a system of 13 DNA methylation markers, corresponding to the promoter regions of theEGFLAM, RXRA, MAFA, TMEM176A/TMEM176B, KHSRP, TMEM200B, ABCG4, GSG1L, CLDN7, CXCL14, DLK2, AIFM3 and SOX8 genes, for the detection of minimal residual disease in pediatric acute myeloid leukemia.