Ethnic differences in the association of thrombophilic polymorphisms with obstetric complications in Slovak and Roma (Gypsy) populations.

AIMS: Hereditary as well as acquired thrombophilia is associated with a higher incidence of severe obstetric complications such as preeclampsia, spontaneous pregnancy loss, placental abruption, and fetal growth retardation. The aim of our study was to examine the association of selected thrombophilic polymorphisms (factor V Leiden, MTHFR C677T, and MTHFR A1298C) with pregnancy complications in the Slovak majority population and the Roma (Gypsy) ethnic population. The study included 354 women; 120 patients and 105 controls from the Slovak majority population, 50 patients and 79 controls from the Slovak Roma population. Genotyping was performed by the real-time polymerase chain reaction method using TaqMan(®) MGB probes. RESULTS: A statistically significant higher frequency of factor V Leiden (p=0.001, odds ratio [OR]=5.9) and MTHFR C677T polymorphism (p=0.011, OR=1.7) was observed in the Slovak majority patient group compared to the control group. The incidence of MTHFR A1298C polymorphism between patients and controls did not differ significantly. None of the three polymorphisms studied was in association with pregnancy complications in the group of Roma women. CONCLUSIONS: Our study has confirmed the variable distribution of selected thrombophilic polymorphisms in different ethnic groups as well as their various effects on the clinical phenotype.

Y-SNP analysis versus Y-haplogroup predictor in the Slovak population.

Human Y-chromosome haplogroups are important markers used mainly in population genetic studies. The haplogroups are defined by several SNPs according to the phylogeny and international nomenclature. The alternative method to estimate the Y-chromosome haplogroups is to predict Y-chromosome haplotypes from a set of Y-STR markers using software for Y-haplogroup prediction. The purpose of this study was to compare the accuracy of three types of Y-haplogroup prediction software and to determine the structure of Slovak population revealed by the Y-chromosome haplogroups. We used a sample of 166 Slovak males in which 12 Y-STR markers were genotyped in our previous study. These results were analyzed by three different software products that predict Y-haplogroups. To estimate the accuracy of these prediction software, Y-haplogroups were determined in the same sample by genotyping Y-chromosome SNPs. Haplogroups were correctly predicted in 98.80% (Whit Athey's Haplogroup Predictor), 97.59% (Jim Cullen's Haplogroup Predictor) and 98.19% (YPredictor by Vadim Urasin 1.5.0) of individuals. The occurrence of errors in Y-chromosome haplogroup prediction suggests that the validation using SNP analysis is appropriate when high accuracy is required. The results of SNP based haplotype determination indicate that 39.15% of the Slovak population belongs to R1a-M198 lineage, which is one of the main European lineages.

Founder mutations in NDRG1 and HK1 genes are common causes of inherited neuropathies among Roma/Gypsies in Slovakia.

Autosomal recessive forms of Charcot-Marie-Tooth disease (CMT) account for less than 10 % of all CMT cases, but are more frequent in the populations with a high rate of consanguinity. Roma (Gypsies) are a transnational minority with an estimated population of 10 to 14 million, in which a high degree of consanguineous marriages is a generally known fact. Similar to the other genetically isolated founder populations, the Roma harbour a number of unique or rare autosomal recessive disorders, caused by "private" founder mutations. There are three subtypes of autosomal recessive CMT with mutations private to the Roma population: CMT4C, CMT4D and CMT4G. We report on the molecular examination of four families of Roma origin in Slovakia with early-onset demyelinating neuropathy and autosomal recessive inheritance. We detected mutation p.R148X (g.631C>T) in the NDRG1 (NM_006096.3) gene in two families and mutation g.9712G>C in the HK1 (NM_033498) gene in the other two families. These mutations cause CMT4D and CMT4G, respectively. The success of molecular genetic analysis in all families confirms that autosomal recessive forms of CMT caused by mutations on the NDRG1 and HK1 genes are common causes of inherited neuropathies among Slovak Roma. Providing genetic analysis of these genes for patients with Roma origin as a common part of diagnostic procedure would contribute to a better rate of diagnosed cases of demyelinating neuropathy in Slovakia and in other countries with a Roma minority.

The frequency of factor V Leiden and prothrombin G20210A mutations in Slovak and Roma (Gypsy) ethnic group of Eastern Slovakia.

Factor V Leiden and prothrombin G20210A are the two most prevalent causes of inherited thrombophilia. The prevalence of these mutations varies widely in healthy Caucasian population. The aim of our study was to determine the frequency of factor V Leiden and prothrombin G20210A mutations in Slovak and Roma ethnic group from Eastern Slovakia. We analyzed 540 asymptomatic individuals (269 individuals of Slovak ethnicity and 271 individuals of Roma ethnicity) by real-time PCR method. The detected allele frequencies were 2.97 versus 6.64 % for factor V Leiden (p = 0.0049), and 0.74 versus 0.92 % for prothrombin mutation (p = 0.7463) in Slovak and Roma population, respectively. The Roma ethnic group had significantly higher prevalence of factor V Leiden mutation when compared to Slovak ethnic group. The allele frequency of factor V Leiden in ethnic Romanies from Eastern Slovakia was one of the highest in Europe. Our results confirm an uneven geographical and ethnic distribution of factor V Leiden.

Unique frequencies of HFE gene variants in Roma/Gypsies.

The aim of this study was to assess the frequencies of three hemochromatosis gene (HFE) mutations in ethnic Roma/Gypsies in Slovakia. A cohort of 367 individuals representing general population and not preselected for health status was genotyped by TaqMan real-time PCR assay for C282Y, H63D and S65C mutations in HFE gene. A unique genetic profile was revealed: C282Y is found in the highest frequency of all Central European countries (4.90%), while the frequency of H63D mutation (4.09%) is lower than any reported in Europe so far. S65C mutation was not present in the cohort. These mutation frequencies can be explained rather by gene influx and genetic isolation than by genetic inheritance from a former Roma/Gypsy homeland.

Association of the FTO rs9939609 polymorphism with obesity in Roma/Gypsy population.

The rs9939609 SNP located in the first intron of the fat mass and obesity associated gene (FTO) has been found to be associated with common obesity mainly in populations of European descent. The Roma/Gypsy population as an ethnic minority of Asian Indian origin is well known for its adverse health status with a high prevalence of obesity. The main aim of this study was to examine the contribution of the rs9939609 FTO polymorphism to the high prevalence of obesity in the Roma/Gypsy population. Following a number of anthropometric measurements, the FTO rs9939609 polymorphism was genotyped in 312 Roma/Gypsy individuals. We observed significant differences in body mass index (BMI), waist circumference, and waist-to-hip ratio between different genotypes (P = 0.003, P = 0.012, and P = 0.03, respectively). The waist circumference in the subjects with AA genotype was about 7.1 cm larger than in those with TT genotypes (P = 0.005). However, the strongest association of minor allele A of the rs9939609 FTO polymorphism was found with BMI (odds ratio, 1.55; 95% confidence interval, 1.129-2.128; P = 0.007), even after adjusting for age, sex, and smoking status. This study provides the first report of allele and genotype frequencies for the rs9939609 polymorphism and also the first evidence of the association of the FTO variant with obesity in the Roma/Gypsy population.

Incidence of microdeletions in the AZF region of the Y chromosome in Slovak patients with azoospermia.

AIMS: The Y chromosome accumulates male-related genes including sex-determining region of Y-chromosome (SRY) and several spermatogenesis-related genes. The long arm contains azoospermia factor (AZF) region (including sub-regions AZFa, AZFb and AZFc). Microdeletions in this region are responsible for azoospermia and oligospermia and result in the male infertility. The aim of this study was to analyze incidence of microdeletions in the AZF region of Y chromosome in patients with azoospermia from Slovakia. PATIENTS AND METHODS: Over the period from 2005 to 2009 a total of 239 men (mean age 31.74 years) were analyzed. The diagnosis of azoospermia was established on the basis of semen analysis. All patient samples were analyzed cytogenetically. Chromosomal analysis was performed on all patients on cultured lymphocytes from peripheral blood. For exact diagnosis of microdeletions in AZF region we used a PCR-method using a set of sequence-tagged sites from all AZF sub-regions (according to the recommendation by the European Academy of Andrology and the European Quality Monitoring Network Group). RESULTS: Among our 226 patients with azoospermia and with normal karyotype, 8 patients (mean age 30.6 years) had microdeletions in the AZF region of the Y chromosome (3.35%). Considering particular types of deletions we determined deletions in each region AZFa,b,c but also a complete deletion of the entire AZF region. The presence of microdeletion(s) in the AZFc region was the most frequent. In our study we found 12 patients (5%) with 47,XXY karyotype (Klinefelter syndrome), but these patients didn't have microdeletion of Y chromosomes. CONCLUSION: The study confirmed that percentage of microdeletions in the AZF region is low in Slovak azoospermic patients, but important from a prognostic view.

Allele frequencies and population data for 11 Y-chromosome STRs in samples from Eastern Slovakia.

Haplotype data of 11 Y-STR loci (DYS391, DYS389I, DYS439, DYS389II, DYS438, DYS437, DYS19, DYS392, DYS393, DYS390 and DYS385) was obtained from 629 Slovak Caucasian men living in Eastern Slovakia. A total of 474 haplotypes were identified, of which 395 were unique. The haplotype diversity value was 0.9982. Pairwise haplotype distances showed that the Eastern Slovak Caucasian population is not significantly different from the Slavs populations and is separated from the Balkan nations and the German speaking populations.

Comparison of Y-STR polymorphisms in three different Slovak population groups.

Eleven Y-chromosomal microsatellite loci included in the Powerplex Y multiplex kit were analyzed in different Slovak population samples: Habans (n = 39), Romanies (n = 100) and Slovak Caucasian (n = 148) individuals, respectively, from different regions of Slovakia. The analysis of molecular variance between populations indicated that 89.27% of the haplotypic variations were found within populations and only 10.72% between populations (Fst = 0.1027; p = 0.0000). The haplotype diversities were ranging from 0.9258 to 0.9978, and indicated a high potential for differentiating between male individuals. The study reports differences in allele frequencies between the Romanies, Habans and Slovak Caucasian men. Selected loci showed that both the Romany and Haban population belonged to endogamous and relatively small founder population groups, which developed in relatively reproductive isolated groups surrounded by the Slovak Caucasian population.