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Background Genomic surveillance of SARS-CoV-2 in Portugal was rapidly implemented by the National Institute of Health in the early stages of the COVID-19 epidemic, in collaboration with more than 50 laboratories distributed nationwide.... more
Background Genomic surveillance of SARS-CoV-2 in Portugal was rapidly implemented by the National Institute of Health in the early stages of the COVID-19 epidemic, in collaboration with more than 50 laboratories distributed nationwide. Methods By applying recent phylodynamic models that allow integration of individual-based travel history, we reconstructed and characterized the spatio-temporal dynamics of SARS-CoV-2 introductions and early dissemination in Portugal. Results We detected at least 277 independent SARS-CoV-2 introductions, mostly from European countries (namely the United Kingdom, Spain, France, Italy, and Switzerland), which were consistent with the countries with the highest connectivity with Portugal. Although most introductions were estimated to have occurred during early March 2020, it is likely that SARS-CoV-2 was silently circulating in Portugal throughout February, before the first cases were confirmed. Conclusions Here we conclude that the earlier implementatio...
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disequilibrium and diversity for three genomic regions
Background Early diagnosis and treatment are improving significantly the quality of life of patients with cystic fibrosis (CF). This recessive disease is caused by a great variability of mutations in the CF transmembrane conductance... more
Background Early diagnosis and treatment are improving significantly the quality of life of patients with cystic fibrosis (CF). This recessive disease is caused by a great variability of mutations in the CF transmembrane conductance (CFTR) gene, whose spectrum and frequency can be different across populations. Methods We performed a retrospective cross-sectional study of CF patients from the island of São Miguel (Azores, Portugal) through a clinical, genealogical, genetic and epidemiological investigation. The clinical course of patients was analyzed as a whole and according to their genotype. Results We identified 14 CF patients within a 23-year period, corresponding to a cumulative incidence of 1:3012 births, being three of them born from consanguineous unions. Genetic analysis revealed three CFTR genotypes: p.[Ser4Ter];[Gln1100Pro] was present in one patient with a less severe phenotype (1/14); c.[120del23];p.[Phe508del], a very rare one (2/14); and p.[Phe508del];[Phe508del] in t...
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Leptospirosis is a worldwide zoonotic and recognized neglected infectious disease. It has been observed that only a proportion of individuals exposed to pathogenic species of Leptospira become infected and develop clinically evident... more
Leptospirosis is a worldwide zoonotic and recognized neglected infectious disease. It has been observed that only a proportion of individuals exposed to pathogenic species of Leptospira become infected and develop clinically evident disease. Moreover, little information is available in subsequent reinfections. In the present study, we determine if a first infection with leptospirosis protects against subsequent reinfection, and investigate which of the host genetic factors are involved in the susceptibility and resistance to leptospirosis. We conducted, in 2011, a retrospective hospital-based case-control study in the São Miguel Island population (Azores archipelago). In order to determine the seropositivity against pathogenic Leptospira after the first episode of leptospirosis, we performed a serological evaluation in 97 unrelated participants diagnosed with leptospirosis between 1992 and 2011. The results revealed that 46.4% of the 97 participants have circulating anti-Leptospira ...
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Research Interests: Evolutionary Biology, Genetics, Human Genetics, Population Genetics, Statistical Analysis, and 14 moreBiology, Genetic Diversity, Population, Genetic Structure, Population History, Polymerase Chain Reaction, Microsatellite, Y chromosome, Genetic Differentiation, Short Tandem Repeat, Genetic distance, microsatellite loci, Blood Donor, and Genetic background
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Summary Background The Azorean population presents the highest standardized mortality rate for cardiovascular diseases (CVD) when compared to mainland Portugal and other populations. Since thrombosis is a common cause of CVD, we assessed... more
Summary Background The Azorean population presents the highest standardized mortality rate for cardiovascular diseases (CVD) when compared to mainland Portugal and other populations. Since thrombosis is a common cause of CVD, we assessed four polymorphisms in three thrombotic risk genes – F5 (G1691A), F2 (G20210A) and MTHFR (C677T, A1298C), in 469 healthy blood donors from São Miguel Island (Azores). We also analysed the CYP2C9 (C430T, A1075C) and VKORC1 (G1639A) variants in fifty-eight individuals with predisposition to thrombosis (possessing at least one variation in F5 or F2 genes and one in MTHFR) to evaluate their warfarin drug response genetic profiles. Results Among the 469 individuals, the data showed that thrombotic risk allele frequencies – 1691A (4.9%), 20210A (1.8%), 677T (41.7%) and 1298C (24.8%) – were similar to other Caucasians, but significantly different from mainland Portuguese (χ2, p < 0.001). The combined analysis of these variants identified twenty-two diffe...
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Currently, direct detection of Leptospira can be done in clinical laboratories by conventional and by real-time PCR (qRT-PCR). We tested a biobank of paired samples of serum and urine from the same patient (202 patients) presenting at the... more
Currently, direct detection of Leptospira can be done in clinical laboratories by conventional and by real-time PCR (qRT-PCR). We tested a biobank of paired samples of serum and urine from the same patient (202 patients) presenting at the hospital in an area endemic for leptospirosis using qRT-PCR followed by high resolution melting (HRM) analysis. The results were compared with those obtained by conventional nested PCR and with the serologic gold standard microscopic agglutination test (MAT). Differences were resolved by sequencing. qRT-PCR-HRM was positive for 46 of the 202 patients (22.7%, accuracy 100%) which is consistent with known prevalence of leptospirosis in the Azores. MAT results were positive for 3 of the 46 patients (6.5%). Analysis of paired samples allowed us to identify the illness point at which patients presented at the hospital: onset, dissemination or excretion. The melting curve analysis of Leptospira species revealed that 60.9% (28/46) of patients were infecte...
Epidermolysis bullosa simplex with muscular dystrophy (EBS-MD; OMIM #226670) is an autosomal recessive disease, characterized mainly by skin blistering at birth or shortly thereafter, progressive muscle weakness, and rarely by alopecia.... more
Epidermolysis bullosa simplex with muscular dystrophy (EBS-MD; OMIM #226670) is an autosomal recessive disease, characterized mainly by skin blistering at birth or shortly thereafter, progressive muscle weakness, and rarely by alopecia. EBS-MD is caused by mutations in the PLEC gene (OMIM *601282), which encodes plectin, a structural protein expressed in several tissues, including epithelia and muscle. We describe a patient affected with EBS-MD and diffuse alopecia in which we identified a novel pathogenic mutation by PCR amplification of all coding exons and exon-intron boundaries of PLEC gene, followed by bidirectional Sanger sequencing. The patient, a 28-year-old female and only child of consanguineous healthy parents, was born after uneventful pregnancy. At 2 days of age, she developed skin and oral mucosal blistering, accompanied by voice hoarseness. On physical examination as an adult, we observed diffuse non-scarring alopecia on the scalp, onychodystrophy (pachyonychia) in al...
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Background: Epidermolysis bullosa simplex with muscular dystrophy (EBS-MD; OMIM #226670) is an autosomal recessive disease, characterized mainly by skin blistering at birth or shortly thereafter, progressive muscle weakness, and rarely by... more
Background: Epidermolysis bullosa simplex with muscular dystrophy (EBS-MD; OMIM #226670) is an autosomal recessive disease, characterized mainly by skin blistering at birth or shortly thereafter, progressive muscle weakness, and rarely by alopecia. EBS-MD is caused by mutations in the PLEC gene (OMIM *601282), which encodes plectin, a structural protein expressed in several tissues, including epithelia and muscle. We describe a patient affected with EBS-MD and diffuse alopecia in which we identified a novel pathogenic mutation by PCR amplification of all coding exons and exon–intron boundaries of PLEC gene, followed by bidirectional Sanger sequencing. Case presentation: The patient, a 28-year-old female and only child of consanguineous healthy parents, was born after uneventful pregnancy. At 2 days of age, she developed skin and oral mucosal blistering, accompanied by voice hoarseness. On physical examination as an adult, we observed diffuse non-scarring alopecia on the scalp, onych...
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Myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) share common features: elevated oxidative stress, DNA repair deficiency, and aberrant DNA methylation. We performed a hospital-based case-control study to evaluate the... more
Myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) share common features: elevated oxidative stress, DNA repair deficiency, and aberrant DNA methylation. We performed a hospital-based case-control study to evaluate the association in variants of genes involved in oxidative stress, folate metabolism, DNA repair, and DNA methylation with susceptibility and prognosis of these malignancies. To that end, 16 SNPs (one per gene: CAT, CYBA, DNMT1, DNMT3A, DNMT3B, GPX1, KEAP1, MPO, MTRR, NEIL1, NFE2F2, OGG1, SLC19A1, SOD1, SOD2, and XRCC1) were genotyped in 191 patients (101 MDS and 90 AML) and 261 controls. We also measured oxidative stress (reactive oxygen species/total antioxidant status ratio), DNA damage (8-hydroxy-2'-deoxyguanosine), and DNA methylation (5-methylcytosine) in 50 subjects (40 MDS and 10 controls). Results showed that five genes (GPX1, NEIL1, NFE2L2, OGG1, and SOD2) were associated with MDS, two (DNMT3B and SLC19A1) with AML, and two (CYBA and DNMT1) with...
Research Interests: Survival Analysis, Oxidative Stress, Folic acid, Adolescent, DNA repair, and 15 moreSignal Transduction, Acute Myeloid Leukemia, Humans, Female, Male, DNA methylation, Young Adult, Aged, Middle Aged, Genotype, Adult, Prognosis, MOLECULAR CARCİNOGENESİS, Case Control Studies, and Myelodysplastic syndromes
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Congenital heart disease (CHD) is one common birth malformation, accounting for about 30% of total congenital abnormalities. Considering the unknown role of consanguinity in causing CHD, we hypothesised that consanguineous unions and/or... more
Congenital heart disease (CHD) is one common birth malformation, accounting for about 30% of total congenital abnormalities. Considering the unknown role of consanguinity in causing CHD, we hypothesised that consanguineous unions and/or familial aggregation may be frequent in the Azorean Island of São Miguel (Portugal). To that end, we performed a retrospective observational study based on genealogical and molecular analyses. The study enrolled 112 CHD patients from São Miguel Island, which allowed the assessment of type of family (simplex or multiplex), parental consanguinity, and grandparental endogamy. Based on 15 STR markers, we estimated inbreeding coefficient (FIS) in the CHD cohort and healthy control group (N=114). Multiplex families were 37.6% (N=41/109), a rate considerably higher than previously described in the literature (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;15%). Moreover, 9.2% (N=10/109) of the CHD families were consanguineous, mostly derived from third cousin unions, and 20.2% (N=22/109) presented full grandparental endogamy. Higher FIS values were found in patients with parental consanguinity (0.0371) and patent ductus arteriosus (0.0277). This study analysed several genealogical and genetic features related with CHD, revealing the presence of parental consanguinity and extensive familial aggregation in the CHD patients from São Miguel Island.
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Abstract Background: Inter-individual variation in response to statins (efficacy and toxicity) has been described and may be due to polymorphisms implicated in drug pharmacokinetics or pharmacodynamics. Aim: This study investigates... more
Abstract Background: Inter-individual variation in response to statins (efficacy and toxicity) has been described and may be due to polymorphisms implicated in drug pharmacokinetics or pharmacodynamics. Aim: This study investigates clinically relevant pharmacogenes underlying statin response in 170 healthy Azoreans. Methods: Eight SNPs in candidate genes-HMGCR (rs3846662, rs17238540, rs17244841), CETP (rs708272), APOE (rs7412, rs429358) and SLCO1B1 (rs2306283, rs4149056)-were genotyped. Results: The allele frequencies were similar to those reported for European derived populations, excepting SLCO1B1 c.388A&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;G (rs2306283), which has a significant difference when compared with the HapMap CEU population (p = 1 × 10(-8)). The results of statin efficacy showed that 9.1% of Azoreans are APOE4 carriers. This allele has been associated with lower LDLc reduction from statin therapy and also higher LDLc levels at baseline. Regarding SLCO1B1, associated with statin toxicity, 1.8% of individuals have two reduced-function alleles (c.521CC). Conclusion: The results contribute to overcome the lack of knowledge regarding the frequency of pharmacogenetic SNPs and their corresponding haplotypes in targeted populations, such as Azores islands. Moreover, the present work constitutes an initial step to implementing pharmacogenomics in clinical practice where physicians could use a patient&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s genetic make-up to optimize statin therapy, regarding efficiency and myopathy risk.
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Allele frequencies for 15 short tandem repeats (STR) loci were obtained from a sample of 4076 unrelated individuals undergoing paternity testing. The population is from Parana ´ , Southern Brazil. The loci are the most commonly used in... more
Allele frequencies for 15 short tandem repeats (STR) loci were obtained from a sample of 4076 unrelated individuals undergoing paternity testing. The population is from Parana ´ , Southern Brazil. The loci are the most commonly used in forensic and paternity testing, being analyzed by the AmpFlSTR 1 IdentifilerTM (Applied Biosystems) commercial kit. The most polymorphic loci were D2S1338 and
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ABSTRACT Background: Glucuronidation reactions, catalyzed by uridine-diphosphate glucuronosyltransferase (UGT) enzymes, constitute a detoxification process that adds glucuronic acid to endogenous and exogenous compounds, aiding their... more
ABSTRACT Background: Glucuronidation reactions, catalyzed by uridine-diphosphate glucuronosyltransferase (UGT) enzymes, constitute a detoxification process that adds glucuronic acid to endogenous and exogenous compounds, aiding their excretion. UGT1A proteins have been implicated as risk factors for both the development of cancer and adverse drug effects. Methods: Here, we assess the genome of 469 individuals from São Miguel Island (Azores, Portugal) in order to determine the frequencies of polymorphisms and haplotypes in UGT1A1, UGT1A6, and UGT1A7, the co-occurrence of reduced enzyme activity UGT1A variants related to irinotecan toxicity, and to calculate the extent of linkage disequilibrium (LD) in the genomic region encompassing these genes. Results: Allelic analysis disclosed the presence of rare alleles — UGT1A1*36 and UGT1A1*37 — only found in individuals of African descent, and UGT1A 7*4. These alleles confirm our previous results on the São Miguel Island genetic background. We identified five different genotypes in UGT1A1 and UGT1A6 and nine in UGT1A7. Haplotype analysis showed that three haplotypes constituted approximately 80% of the allelic variants. Interestingly, haplotype 3 (UGT1A1*28- UGT1A6*2- UGT1A7*3), with a frequency of 0.235, gathers the three alleles encoding the low-function UGT isoforms. Additionally, LD indicates a strong interaction between functional polymorphisms related to the alteration of the UGT enzyme activity. Conclusions: In summary, the results demonstrate a high variability of alleles and haplotypes, which have important roles in modifying expression and activity of UGTs. The data presented here could improve the understanding of the predisposition to cancers and susceptibility to the adverse effects of irinotecan in the São Miguel Island population.
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The knowledge of a population structure may constitute a powerful tool for mapping genes underlying susceptibility to Mendelian and complex diseases. To obtain a better understanding of the population structure of São Miguel Island... more
The knowledge of a population structure may constitute a powerful tool for mapping genes underlying susceptibility to Mendelian and complex diseases. To obtain a better understanding of the population structure of São Miguel Island (Azorean Archipelago, Portugal), we carried out a surname survey using the surnames listed in the most recent telephone book (2001). We identified 1315 different surnames in a total of 27,621 subscribers. The frequency of the different surnames was used to calculate the following parameters: isonymy (I), random component of inbreeding (FST), genetic diversity according to Fisher (alpha), migration rate according to Karlin-McGregor (v) and Nei&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s genetic distance. Eleven localities were selected, according to population size and geographic distribution, for analysis using the above parameters. Our results show that 51% of Salga&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s population and 52% of Sete Cidades&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s population are represented by six and eight surnames, respectively. These figures demonstrate the effective isolation of these two small places, which are located at opposite ends of São Miguel Island. Salga, Achada, and Sete Cidades present the lowest values of Fisher&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s alpha, indicating less genetic diversity. In contrast, the capital, Ponta Delgada, presents the highest value of alpha (78.13), indicating more genetic diversity. Our data indicate that the clustering of the localities corresponds to the geographic features of the island, where localities close together tend to share similar surnames. In conclusion, the population of São Miguel is relatively homogeneous and may constitute an ideal model for genetic mapping studies.
Research Interests: Genetics, Population Genetics, Genetic Diversity, Human Biology, Population structure, and 13 moreGenetics of complex disease, Humans, Azores, Human Population Genetics, Names, Genetic Map, Population Size, Data Collection, Theoretical Models, Geographic distribution, Inbreeding, Genetic variation, and Genetic distance
The identification of clinically validated genetic variants contributing to complex disorders raise the possibility to investigate... more
The identification of clinically validated genetic variants contributing to complex disorders raise the possibility to investigate individuals&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; risk. In this line of research, the present work aimed to assess the genetic risk for cardiovascular disease (CVD) in Azoreans. Genotyping of 19 SNPs - 9 on 9p21, 5 on LDLR and 5 on USF1 - was performed by TaqMan assays on 170 healthy Azorean individuals. Results demonstrate that the most frequent haplotype in 9p21, with a frequency of 41.4%, is TGGGCGCGC, which harbors all risk alleles. Considering haplotype homozygosity data show that females present higher value of homozygosity for both LDLR (13.5%) and USF1 (15.3%), whereas males present higher value for the 9p21 region (8.2%). Interestingly, genetic profile analysis revealed differences in terms of geographic and gender distribution. The Azorean Central group presented a higher risk for atherosclerosis, 2.7 times higher when compared to the Eastern group, while the Eastern group shows 1.5 times higher risk for dyslipidemias. Moreover, Azorean females demonstrated a 4 times higher risk for dyslipidemias when compared to males, whereas males have an increased risk for atherosclerosis. Although allele frequencies in Azoreans were similar to those reported for the HapMap CEU population, the differences in terms of haplotype and genetic profile distribution must be taken in consideration when assessing genetic risk. Taken together, the data here presented evidence for the need to perform biomedical research and epidemiologic analysis in Azoreans with the aim of developing strategies to CVD prevention, health promotion and population education.
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Background Glucuronidation reactions, catalyzed by uridine-diphosphate glucuronosyltransferase (UGT) enzymes, constitute a detoxification process that adds glucuronic acid to endogenous and exogenous compounds, aiding their excretion. ...
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The knowledge of a population structure may constitute a powerful tool for mapping genes underlying susceptibility to Mendelian and complex diseases. To obtain a better understanding of the population structure of São Miguel Island... more
The knowledge of a population structure may constitute a powerful tool for mapping genes underlying susceptibility to Mendelian and complex diseases. To obtain a better understanding of the population structure of São Miguel Island (Azorean Archipelago, ...
Research Interests: Genetics, Population Genetics, Genetic Diversity, Human Biology, Population structure, and 13 moreGenetics of complex disease, Humans, Azores, Human Population Genetics, Names, Genetic Map, Population Size, Data Collection, Theoretical Models, Geographic distribution, Inbreeding, Genetic variation, and Genetic distance
The identification of clinically validated genetic variants contributing to complex disorders raise the possibility to investigate individuals' risk. In this line of research, the present work aimed to assess the genetic risk for... more
The identification of clinically validated genetic variants contributing to complex disorders raise the possibility to investigate individuals' risk. In this line of research, the present work aimed to assess the genetic risk for cardiovascular disease (CVD) in Azoreans. Genotyping of 19 SNPs - 9 on 9p21, 5 on LDLR and 5 on USF1 - was performed by TaqMan assays on 170 Azorean healthy individuals. Results demonstrate that the most frequent haplotype in 9p21, with a frequency of 41.4%, is TGGGCGCGC, which harbors all risk alleles. Considering haplotype homozygosity data show that females present higher value of homozygosity for both LDLR (13.5%) and USF1 (15.3%), whereas males present higher value for the 9p21 region (8.2%). Interestingly, genetic profiles analysis revealed differences in terms of geographic and gender distribution. The Azorean Central group presented a higher risk for atherosclerosis, 2.7 times higher when compared to Eastern group, while the Eastern group shows ...
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Introduction: We performed a descriptive analysis of molecular diagnosis of infectious agents in the São Miguel Island population, in order to address questions like what is the frequency of clinical requests, is it observable seasonality... more
Introduction: We performed a descriptive analysis of molecular diagnosis of infectious agents in the São Miguel Island population, in order to address questions like what is the frequency of clinical requests, is it observable seasonality of pathogens, and what is the positive rate for the clinical diagnosis. Methodology: This was a retrospective and descriptive study based on 878 individuals suspected of harboring infectious diseases during two consecutive years, 2012–2013. More than 25 different pathogens were investigated by polymerase chain reaction (PCR)-based methods. The individuals were stratified into gender, occupation, and age groups. Results: The pathogen with more clinical requests was hepatitis C virus, investigated in 225 individuals (30.0%), followed by Leptospira spp., in 187 (24.9%). Overall, data demonstrated a gender distribution bias, where 72.9% of cases were males. The age group of 25 to 44 years was the class with more clinical requests. Regarding occupation, a predominance of construction workers (12.0%) was observed, followed by retired workers (11.0%). Patient distribution per year showed a higher number of patients in the fall months. Diagnoses of leptospirosis and respiratory virus infections presented seasonality. Conclusions: The present study provides a valid contribution to the knowledge of the epidemiology of infectious diseases in the São Miguel Island (Azores, Portugal) population.
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Research Interests: Geography, Forensic Science, Polymorphism, Population Genetics, Brazil, and 17 moreForensic Medicine, Quality Control, Biological Sciences, Humans, Paternity, Mutation, Mathematical Sciences, Female, Male, DNA fingerprinting, Rio Grande do Sul, Amelogenin, Short Tandem Repeat, Southern Brazil, Genetic distance, Mutation Rate, and Allele Frequency
In order to obtain a better understanding of the genetic structure of the Azorean population, a specificity and spatial distribution analysis was performed, based on 2,454 different surnames present in the Azorean telephone directory... more
In order to obtain a better understanding of the genetic structure of the Azorean population, a specificity and spatial distribution analysis was performed, based on 2,454 different surnames present in the Azorean telephone directory (2002). We considered as specific surnames those with an absolute frequency ratio equal to or higher than 50%. The results revealed 51 specific surnames in the whole archipelago. The smallest island presents the only surname with 100% specificity (Pedras). In addition, São Miguel island, which contains 54% of the Azorean population, has the highest number of specific surnames (25 specific surnames). The spatial distribution analysis was used to detect genetic similarity between municipalities through the calculation of spatial autocorrelation (Moran's I coefficient). Of 240 surnames included in the analysis, 113 showed statistically significant patterns. Five different patterns were obtained, of which the most relevant was isolation by distance and depression (41.6%). However, 43.4% had no defined pattern. The overall correlogram shows a majority of positive values for distances lower than 49 km and between 269–309 km, indicating high similarity between closer municipalities and between distant municipalities whose populations show historic and sociocultural affinities. In conclusion, our data are in agreement with the historical background of the Azorean population. Am. J. Hum. Biol. 17:634–645, 2005. © 2005 Wiley-Liss, Inc.
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Iron overload is associated with acquired and genetic conditions, the most common being hereditary hemochromatosis (HH) type-I, caused by HFE mutations. Here, we conducted a hospital-based case-control study of 41 patients from the São... more
Iron overload is associated with acquired and genetic conditions, the most common being hereditary hemochromatosis (HH) type-I, caused by HFE mutations. Here, we conducted a hospital-based case-control study of 41 patients from the São Miguel Island (Azores, Portugal), six belonging to a family with HH type-I pseudodominant inheritance, and 35 unrelated individuals fulfilling the biochemical criteria of iron overload compatible with HH type-I. For this purpose, we analyzed the most common HFE mutations- c.845G>A [p.Cys282Tyr], c.187C>G [p.His63Asp], and c.193A>T [p.Ser65Cys]. Results revealed that the family's HH pseudodominant pattern is due to consanguineous marriage of HFE-c.845G>A carriers, and to marriage with a genetically unrelated spouse that is a -c.187G carrier. Regarding unrelated patients, six were homozygous for c.845A, and three were c.845A/c.187G compound heterozygous. We then performed sequencing of HFE exons 2, 4, 5 and their intron-flanking regions....
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Geographic isolation is a significant factor to consider when characterizing human populations. The knowledge of the genetic structure of isolated populations has been of great importance to disease-locus positioning and gene... more
Geographic isolation is a significant factor to consider when characterizing human populations. The knowledge of the genetic structure of isolated populations has been of great importance to disease-locus positioning and gene identification. To investigate the genetic structure of the Azorean population, we conducted a survey based on the frequencies of surnames listed in the 2001 telephone book. We calculated the following parameters: isonymy (I), the random component of inbreeding (F(ST)), genetic diversity according to Fisher (alpha), Karlin-McGregor&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s migration rate (v), and Nei&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s distance. For the 1,271 subscribers and 163 different surnames, Graciosa island presented the lowest value of abundance of surnames (alpha = 15.75), suggesting great genetic isolation compared to the other eight islands. Migration, calculated on the basis of the diversity of surnames within islands, ranged from 0.2747 (Corvo island) to 0.0026 (São Miguel island), indicating that people migrated preferentially toward the economically more developed islands. The value of the random component of inbreeding obtained for the whole population (F(ST) = 0.0039) indicates little genetic differentiation (Wright&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s F(ST) &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). Moreover, isonymy similarity revealed using the UPGMA method shows three subclusters corresponding to the geographic distribution of the islands.
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To study the genetic diversity of São Miguel&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s population we compared 21 microsatellite loci in 204 individuals from São Miguel island and 103... more
To study the genetic diversity of São Miguel&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s population we compared 21 microsatellite loci in 204 individuals from São Miguel island and 103 individuals from mainland Portugal. The results show that São Miguel and mainland Portugal populations have an average gene diversity of 0.767 and 0.765, respectively. Allele frequencies of all markers are comparable to other European populations. This observation is corroborated by the genetic relationships analysis based on the NJ tree and principal component, where São Miguel is closely related to mainland Portugal. Overall, the data suggests that São Miguel does not show population structure and is outbred with high genetic diversity. Moreover, the characterization here described is crucial to predict and explain genotypes implicated in genetic diseases in the Azorean population.