Juliano André Boquett

Self-Assessment of Color Categories and Its Relationship with HLA Profiling in Brazilian Bone Marrow Donors

The Brazil Ministry of Health maintains a Registry of Bone Marrow Donors that corresponds to approximately 12% of the Bone Marrow Donors Worldwide registry. This registry contains information on ethnicity (by self-assessment of color) and HLA-A, -B, and -DRB1 type. The self-assessment of color tool has been extensively used for admixed population characterization. In this context, Brazil represents a highly admixed population, resulting from 5 centuries of colonization and interbreeding, mainly, but not exclusively, among Native Americans, Europeans, and Africans. Here we evaluated self-assessed skin color and HLA genetic information from 71,291 bone marrow donors of southern Brazil to verify how likely is the HLA profiling correspondence within and between self-assessed color groups. We found that HLA itself was a better ancestry indicator than was self-assessed color. Therefore, self-assessment of color in highly admixed populations, such as that of Brazil, is not indicative of higher correspondence in the HLA profiles within skin color groups.

Interaction between TP63 and MDM2 genes and the risk of recurrent pregnancy loss

OBJECTIVE Recent studies have investigated the role of the p53 gene family in reproductive processes. Each member of the gene family acts through different mechanisms: p53 is involved in genomic stability and regulation of blastocyst implantation; p63 acts as a regulator of the quality and maturation of oocytes; and p73 controls the meiotic spindle. Polymorphisms in the genes of the p53 family have been associated with female infertility. One polymorphism in MDM2, the main regulator of the p53 family, has also been associated with this condition. Although polymorphisms in the TP53 gene have been related to recurrent pregnancy loss (RPL), there have been no studies associating polymorphisms in p63 and p73 with RPL. Therefore, the aim of this study was to evaluate the role of polymorphisms in the TP63 (rs17506395), TP73 (rs2273953, rs1801173), and MDM2 (SNP309, rs2279744) genes as risk factors for RPL. STUDY DESIGN A case-control study was conducted in 153 women with RPL and 143 fertile women with at least two living children and no history of pregnancy loss. Molecular analysis was performed by TaqMan Allelic Discrimination assay. The statistical analysis was performed using SPSS software version 20.0 and the chi-square test, Students t-test, Mann-Whitney test and logistic regression to compare the evaluated characteristics between both groups and RPL outcome. RESULTS The allelic and genotypic frequencies did not differ between the groups when analyzed separately, however, the interaction between the TP63 TT and MDM2 TT genotypes was shown to increase the risk of RPL (OR=2.19, CI 95%: 1.28-3.75, p=0.004), even when adjusted for alcohol consumption, smoking, number of pregnancies and ethnicity (OR=1.97, CI 95%: 1.27-3.58, p=0.025). CONCLUSIONS Our results suggest that genes from the p53 family proteins, evaluated here, have an influence on the risk of RPL.

Maternal SNPs in the p53 Pathway: Risk Factors for Trisomy 21?

The p53 family and its regulatory pathway play an important role as regulators of developmental processes, limiting the propagation of aneuploid cells. Its dysfunction or imbalance can lead to pathological abnormalities in humans. The aim of this study was to evaluate the effect of maternal polymorphisms TP53 c.215G>C (P72R), TP73 4 c.-30G>A and 14 c.-20C>T, MDM2 c.14+309T>G (SNP309), MDM4 c.753+572C>T and USP7 c.2719-234G>A as risk factors for Down Syndrome (DS) birth. A case-control study was conducted with 263 mothers of DS children and 196 control mothers. The distribution of these genotypic variants was similar between case and control mothers. However, the combined alleles TP53 C and MDM2 G, and TP53 C and USP7 A increased the risk of having offspring with DS (OR = 1.84 and 1.77; 95% CI; P < 0.007 and 0.018, respectively). These results suggest that, although the individual polymorphisms were not associated with DS birth, the effect of the combined genotypes among TP53, MDM2 and USP7 genes indicates a possible role of TP53 and its regulatory pathway as a risk factor for aneuploidy.

Polymorphisms of the Apoptotic genes TP53 and MDM2 and Preeclampsia Development

Preeclampsia (PE) is a multisystemic disorder responsible by high levels of maternal/fetal mortality and morbidity. Although its exact physiology is not well established, apoptosis has a pivotal role in PE pathophysiology, and an elevated rate of cell death is related to PE development. Here it was performed a case-control study, where the frequencies of two polymorphisms in major genes of the apoptosis pathway (TP53 rs1042522 and MDM2 rs2279744) were genotyped in 119 women suffering PE and 99 without preeclampsia. The genotyping was performed by allelic discrimination using a Taqman SNP genotype analyzer. Considering clinical features, the mean of birth weight was lower among children delivered by PE women (p=0.004). Also, a higher number of children from PE women was classified as having Low Birth Weight (p<0.001). PE women had Cesarian delivery more frequently than controls (p=0.004) and also presented overweight and hypertension (p<0.001). Despite the clinical features, the distribution of the genotypic variants was similar between case and controls, suggesting that the genetic variants evaluated did not directly influence the risk of PE among our subjects.

Twin Peaks: A spatial and temporal study of twinning rates in Brazil

Twin births are an important public health issue due to health complications for both mother and children. While it is known that contemporary factors have drastically changed the epidemiology of twins in certain developed countries, in Brazil, relevant data are still scarce. Thus, we carried out a population-based study of live births in spatial and temporal dimensions using data from Brazils Live Birth Information System, which covers the entire country. Over 41 million births registered between 2001 and 2014 were classified as singleton, twin or multiple. Twinning rates (TR) averaged 9.41 per 1,000 for the study period and a first-order autoregressive model of time-series analysis revealed a global upward trend over time; however, there were important regional differences. In fact, a Cluster and Outlier Analysis (Anselin Local Morans I) was performed and identified clusters of high TR in an area stretching from the south of Brazils Northeast Region to the South Region (Global Moran Index = 0.062, P < 0.001). Spearmans correlation coefficient and a Wilcoxon matched pairs test revealed a positive association between Human Development Index (HDI) and TRs in different scenarios, suggesting that the HDI might be an important indicator of childbearing age and assisted reproduction techniques in Brazil. Furthermore, there was a sharp increase of 26.42% in TR in women aged 45 and over during study period. The upward temporal trend in TRs is in line with recent observations from other countries, while the spatial analysis has revealed two very different realities within the same country. Our approach to TR using HDI as a proxy for underlying socioeconomic changes can be applied to other developing countries with regional inequalities resembling those found in Brazil.

Spatial analyzes of HLA data in Rio Grande do Sul, south Brazil: genetic structure and possible correlation with autoimmune diseases

BackgroundHLA genes are the most polymorphic of the human genome and have distinct allelic frequencies in populations of different geographical regions of the world, serving as genetic markers in ancestry studies. In addition, specific HLA alleles may be associated with various autoimmune and infectious diseases. The bone marrow donor registry in Brazil is the third largest in the world, and it counts with genetic typing of HLA-A, -B, and -DRB1. Since 1991 Brazil has maintained the DATASUS database, a system fed with epidemiological and health data from compulsory registration throughout the country.MethodsIn this work, we perform spatial analysis and georeferencing of HLA genetic data from more than 86,000 bone marrow donors from Rio Grande do Sul (RS) and data of hospitalization for rheumatoid arthritis, multiple sclerosis and Crohn’s disease in RS, comprising the period from 1995 to 2016 obtained through the DATASUS system. The allele frequencies were georeferenced using Empirical Bayesian Kriging; the diseases prevalence were georeferenced using Inverse Distance Weighted and cluster analysis for both allele and disease were performed using Getis-Ord Gi* method. Spearman’s test was used to test the correlation between each allele and disease.ResultsThe results indicate a HLA genetic structure compatible with the history of RS colonization, where it is possible to observe differentiation between regions that underwent different colonization processes. Spatial analyzes of autoimmune disease hospitalization data were performed revealing clusters for different regions of the state for each disease analyzed. The correlation test between allelic frequency and the occurrence of autoimmune diseases indicated a significant correlation between the HLA-B*08 allele and rheumatoid arthritis.ConclusionsGenetic mapping of populations and the spatial analyzes such as those performed in this work have great economic relevance and can be very useful in the formulation of public health campaigns and policies, contributing to the planning and adjustment of clinical actions, as well as informing and educating professionals and the population.

Erythropoietin on cycling performance

In a recent study published in The Lancet Haematology, Jules Heuberger and colleagues1 suggested that the use of recombinant human erythropoietin (rHuEPO) did not affect road race performance in a sample of amateur cyclists. This finding was surprising, since it is generally assumed that increased red blood cell mass would benefit endurance sports. Their study used a double-blind, randomised, placebo-controlled design and measured exercise performance in maximal, submaximal, and road race tests, finding significant differences between groups only during the maximal exercise test. The authors conclude that the effect of rHuEPO is undetectable in a real-life cycling race, and suggest that other potential performance-enhancing drugs (PEDs) should be tested using a similar study design. Although we welcome the initiative of Heuberger and colleagues1 to use a randomised clinical trial in sports doping research, we argue that their conclusion should be met with caution. In this Correspondence, we bring philosophical and practical issues that may be worth considering in further studies. Two fundamental questions are (1) how much gain in performance is required for a drug to be considered a PED? and (2) how much statistical power a study should use to add (or clear) a drug from a list of banned substances? Heuberger and colleagues’ study1 aimed at 80% power to detect a difference in maximal oxygen consumption (VO2 max) of 1·7 mL/min per kg. Is this enough? Given the ethical damage to sports caused by doped athletes, we argue that clinical trials on (potential) PEDs should be high powered (perhaps >95%) to detect small differences in relevant physiological parameters, as minimal differences in race times (or other performance outcomes) may determine the winners. Unavoidably, sample sizes should be large. There may be other confounding factors as well. Can results based on amateur athletes be extrapolated to elite athletes? Do all individuals respond similarly to the PED under study? It seems plausible that differences among individuals may result from distinct genetic backgrounds, individual differences in training programmes, race strategy, and experience. In the study by Heuberger and colleagues,1 several outcomes in both maximal and submaximal tests showed a trend towards an improved performance in the rHuEPO group, which may suggest that a similar study with larger sampling would be able to show statistical differences in a submaximal or even a race test. The relevance of clinical trials in PEDs research is undeniable, but planning such studies should consider several still unresolved issues.

Angiogenesis and oxidative stress-related gene variants in recurrent pregnancy loss

Recurrent pregnancy loss (RPL) affects ~3-5% of couples attempting to conceive and in around 50% of cases the aetiology remains unknown. Adequate vascularisation and placental circulation are indispensable for the development of a normal pregnancy. Prostaglandin-endoperoxide synthase 2 (PTGS2), vascular endothelial growth factor (VEGF) and the nitric oxide (NO) systems play important roles in reproductive physiology, participating in several steps including implantation and apoptosis of trophoblast cells. In this study we evaluated genetic polymorphisms in the inducible nitric oxide synthase (NOS2), PTGS2 and VEGFA genes as susceptibility factors for RPL. A case-control study was conducted in 149 women having two or more miscarriages and 208 controls. Allele and genotype distributions of the polymorphisms studied in the two groups were not statistically different. However, the dominant model showed that the presence of variant T (TT/GT) of rs2779249 (-1290G>T) of NOS2 was significantly associated with RPL (OR=1.58, CI 95%=1.03-2.44; P=0.037). The increased risk remained significant when adjusted for number of pregnancies, alcohol consumption and ethnicity (OR=1.92, CI95%=1.18-3.11; P=0.008). These results suggest that the variant genotypes of the functional polymorphism rs2779249 in the NOS2 promoter are a potential risk for RPL, possibly due to oxidative stress mechanisms.