@article {7773, title = {A rapid screening of ancestry for genetic association studies in an admixed population from Pernambuco, Brazil.}, journal = {Genet Mol Res}, volume = {14}, year = {2015}, month = {2015}, pages = {2876-84}, abstract = {

Genetic association studies determine how genes influence traits. However, non-detected population substructure may bias the analysis, resulting in spurious results. One method to detect substructure is to genotype ancestry informative markers (AIMs) besides the candidate variants, quantifying how much ancestral populations contribute to the samples{\textquoteright} genetic background. The present study aimed to use a minimum quantity of markers, while retaining full potential to estimate ancestries. We tested the feasibility of a subset of the 12 most informative markers from a previously established study to estimate influence from three ancestral populations: European, African and Amerindian. The results showed that in a sample with a diverse ethnicity (N = 822) derived from 1000 Genomes database, the 12 AIMs had the same capacity to estimate ancestries when compared to the original set of 128 AIMs, since estimates from the two panels were closely correlated. Thus, these 12 SNPs were used to estimate ancestry in a new sample (N = 192) from an admixed population in Recife, Northeast Brazil. The ancestry estimates from Recife subjects were in accordance with previous studies, showing that Northeastern Brazilian populations show great influence from European ancestry (59.7\%), followed by African (23.0\%) and Amerindian (17.3\%) ancestries. Ethnicity self-classification according to skin-color was confirmed to be a poor indicator of population substructure in Brazilians, since ancestry estimates overlapped between classifications. Thus, our streamlined panel of 12 markers may substitute panels with more markers, while retaining the capacity to control for population substructure and admixture, thereby reducing sample processing time.

}, issn = {1676-5680}, doi = {10.4238/2015.March.31.18}, author = {Coelho, A V C and Moura, R R and Cavalcanti, C A J and Guimar{\~a}es, R L and Sandrin-Garcia, P and Crovella, S and Brand{\~a}o, L A C} } @article {7690, title = {Short Communication FYB polymorphisms in Brazilian patients with type I diabetes mellitus and autoimmune polyglandular syndrome type III.}, journal = {Genet Mol Res}, volume = {14}, year = {2015}, month = {2015}, pages = {29-33}, abstract = {

The aim of this study was to perform an association study between seven Fyn-binding protein gene (FYB)-tag single nucleotide polymorphisms (SNPs) and type I diabetes mellitus (T1DM), as well as with disease age of onset. We also assessed the role of FYB SNPs in the insurgence of autoimmune polyglandular syndrome type III (APSIII), characterized by the simultaneous presence of autoimmune thyroid disease and celiac disease, in patients with T1DM from a Northeastern Brazilian population. One hundred and seventy-seven patients with T1DM and 190 healthy individuals were genotyped for seven tag SNPs, covering most of the FYB locus, using real-time polymerase chain reaction amplification. There was no significant difference in the distribution of allele and genotype frequencies among patients and healthy individuals. Moreover, none of the tag SNPs were associated either to T1DM age of onset or to the insurgence of APSIII. However, since the FYB protein is a key component in T cell response, its gene variants might play a role in protein function, which might be testable in a population with different genetic backgrounds or by using functional assays.

}, issn = {1676-5680}, doi = {10.4238/2015.January.15.4}, author = {Addobbati, C J C and de Azev{\^e}do Silva, J and Tavares, N A C and Araujo, J and Guimar{\~a}es, R L and Brand{\~a}o, L and Crovella, S and Sandrin-Garcia, P} } @article {1870, title = {Functional single-nucleotide polymorphisms in the DEFB1 gene are associated with systemic lupus erythematosus in Southern Brazilians.}, journal = {Lupus}, volume = {21}, year = {2012}, month = {2012 May}, pages = {625-31}, abstract = {

Systemic lupus erythematosus (SLE) is an autoimmune disease that results in inflammation and tissue damage. The etiology of SLE remains unknown, but recent studies have shown that the innate immune system may have a role in SLE pathogenesis through the secretion of small cationic peptides named defensins. The aim of the study was to determine the possible involvement in SLE of three functional single nucleotide polymorphisms (SNPs) (c.-52G>A, c.-44C>G and c.-20G>A) in the 5{\textquoteright}UTR region of DEFB1 gene, by analyzing them in a population of 139 SLE patients and 288 healthy controls. The c.-52G>A SNP showed significant differences in allele and genotype frequency distribution between SLE patients and controls (p = 0.01 and p = 0.02 respectively) indicating protection against SLE (A allele, OR = 0.68, AA genotype OR = 0.51). Significant differences were also observed for c.-44C>G SNP, the C/G genotype being associated with susceptibility to SLE (OR = 1.60, p = 0.04). Moreover, statistically significant differences between patients and controls were found for two DEFB1 haplotypes (GCA and GGG, p = 0.01 and p = 0.02 respectively). When considering DEFB1 SNPs and SLE clinical and laboratory manifestations, significant association was found with neuropsychiatric disorders, immunological alterations and anti-DNA antibodies. In conclusion, our results evidence a possible role for the c.-52G>A and c.-44C>G DEFB1 polymorphisms in SLE pathogenesis, that can be considered as possible risk factors for development of disease and disease-related clinical manifestations. Additional studies are needed, to corroborate these results as well as functional studies to understand the biological role of these SNPs in the pathogenesis of SLE.

}, keywords = {Adolescent, Adult, Aged, beta-Defensins, Brazil, Case-Control Studies, Female, Genetic Predisposition to Disease, Genotype, Haplotypes, Humans, Lupus Erythematosus, Systemic, Male, Middle Aged, Polymorphism, Single Nucleotide, Risk Factors, Young Adult}, issn = {1477-0962}, doi = {10.1177/0961203312436858}, author = {Sandrin-Garcia, P and Brand{\~a}o, L A C and Guimar{\~a}es, R L and Pancoto, J A T and Donadi, E A and Lima-Filho, J L de and Segat, L and Crovella, S} } @article {1812, title = {Mannose-binding lectin and MBL-associated serine protease-2 gene polymorphisms in a Brazilian population from Rio de Janeiro.}, journal = {Int J Immunogenet}, volume = {39}, year = {2012}, month = {2012 Feb}, pages = {32-8}, abstract = {

Mannose-binding lectin (MBL) is a protein able to bind to carbohydrate patterns on pathogen membranes; upon MBL binding, its{\textquoteright} associated serine protease MBL-associated serine protease type 2 (MASP2) is autoactivated, promoting the activation of complement via the lectin pathway. For both MBL2 and MASP2 genes, the frequencies of polymorphisms are extremely variable between different ethnicities, and this aspect has to be carefully considered when performing genetic studies. While polymorphisms in the MBL-encoding gene (MBL2) have been associated, depending upon ethnicity, with several diseases in different populations, little is known about the distribution of MASP2 gene polymorphisms in human populations. The aim of our study was thus to determine the frequencies of MBL2 (exon 1 and promoter) and MASP2 (p.D371Y) polymorphisms in a Brazilian population from Rio de Janeiro. A total of 294 blood donor samples were genotyped for 27 polymorphisms in the MBL2 gene by direct sequencing of a region spanning from the promoter polymorphism H/L rs11003125 to the rs1800451 polymorphism (at codon 57 in the first exon of the gene). Genotyping for MASP2 p.D371Y was carried out using fluorogenic probes. To our knowledge, this is the first study reporting the prevalence of the MASP2 p.D371Y polymorphism in a Brazilian population. The C allele frequency 39\% is something intermediate between the reported 14\% in Europeans and 90\% in Sub-Saharan Africans. MBL2 polymorphisms frequencies were quite comparable to those previously reported for admixed Brazilians. Both MBL2 and MASP2 polymorphisms frequencies reported in our study for the admixed Brazilian population are somehow intermediate between those reported in Europeans and Africans, reflecting the ethnic composition of the southern Brazilian population, estimated to derive from an admixture of Caucasian (31\%), African (34\%) and Native American (33\%) populations. In conclusion, our population genetic study describes the frequencies of MBL2 and MASP2 functional SNPs in a population from Rio de Janeiro, with the aim of adding new information concerning the distribution of these SNPs in a previously unanalysed Brazilian population, thus providing a new genetic tool for the evaluation of the association of MBL2 and MASP2 functional SNPs with diseases in Brazil, with particular emphasis on the state of Rio de Janeiro.

}, keywords = {Adolescent, Adult, Brazil, Ethnic Groups, Exons, Female, Fluorescent Dyes, Gene Frequency, Genetics, Population, Genome, Human, HapMap Project, Humans, Male, Mannose-Binding Lectin, Mannose-Binding Protein-Associated Serine Proteases, Middle Aged, Polymorphism, Single Nucleotide, Promoter Regions, Genetic, Sequence Analysis, DNA, Young Adult}, issn = {1744-313X}, doi = {10.1111/j.1744-313X.2011.01052.x}, author = {Ferraroni, N R and Segat, L and Guimar{\~a}es, R L and Brand{\~a}o, L A C and Crovella, S and Constantino-Silva, R N and Loja, C and da Silva Duarte, A J and Grumach, A S} }