Assessing Individual Interethnic Admixture and Population Substructure Using a 48-Insertion-Deletion (INSEL) Ancestry-Informative Marker (AIM) Panel

Estimating the proportions of different ancestries in admixed populations is very important in population genetics studies, and it is particularly important for detecting population substructure effects in case-control association studies. In this work, a set of 48 ancestry, informative insertion, deletion polymorphisms (INDELs) were selected with the goal of efficiently measuring the proportions of three different ancestries (sub-Saharan African, European, and Native American) in mixed populations. All selected markers can be easily analyzed via multiplex PCR and detected with standard capillary electrophoresis. A total of 593 unrelated individuals representative of European, African, and Native American parental populations were typed, as were 380 individuals from three Brazilian populations with known admixture patterns. As expected, the interethnic admixture estimates show that individuals from southern Brazil present an almost exclusively European ancestry; Afro-descendant communities in the Amazon region, apart from the major African contribution, present some degree of admixture with Europeans and Native Americans; and a sample from Belem, in the northeastern Amazon, shows a significant contribution of the three ethnic groups, although with a greater European proportion. In summary, a panel of ancestry-informative INDELs was optimized and proven to be a variable tool for estimating individual and global ancestry proportions in admixed populations. The ability to accurately infer interethnic admixtures highlights the usefulness of this marker set for assessing population substructure in association studies, particularly those conducted in Brazilian and other Latin American populations sharing trihybrid ancestry patterns. Hum Mutat 31:184-190, 2010. (C) 2009 Wiley-Liss, Inc.

Mitochondrial population genomics supports a single pre-Clovis origin with a coastal route for the peopling of the Americas

It is well accepted that the Americas were the last continents reached by modern humans, most likely through Beringia. However, the precise time and mode of the colonization of the New World remain hotly disputed issues. Native American populations exhibit almost exclusively five mitochondrial DNA (mtDNA) haplogroups (A-D and X). Haplogroups A-D are also frequent in Asia, suggesting a northeastern Asian origin of these lineages. However, the differential pattern of distribution and frequency of haplogroup X led some to suggest that it may represent an independent migration to the Americas. Here we show, by using 86 complete mitochondrial genomes, that all Native American haplogroups, including haplogroup X, were part of a single founding population, thereby refuting multiple-migration models. A detailed demographic history of the mtDNA sequences estimated with a Bayesian coalescent method indicates a complex model for the peopling of the Americas, in which the initial differentiation from Asian populations ended with a moderate bottleneck in Beringia during the last glacial maximum (LGM), around similar to 23,000 to similar to 19,000 years ago. Toward the end of the LGM, a strong population expansion started similar to 18,000 and finished similar to 15,000 years ago. These results support a pre-Clovis occupation of the New World, suggesting a rapid settlement of the continent along a Pacific coastal route.

Human cytomegalovirus reinfection is associated with intrauterine transmission in a highly cytomegalovirus-immune maternal population

OBJECTIVE: To determine contribution of reinfection with new strains of cytomegalovirus in cytomegalovirus seromimmune women to incidence of congenital cytomegalovirus infection. STUDY DESIGN: In 7848 women studied prospectively for congenital cytomegalovirus infection from a population with near universal cytomegalovirus seroimmunity, sera from 40 mothers of congenitally infected infants and 109 mothers of uninfected newborns were analyzed for strain-specific anticytomegalovirus antibodies. RESULTS: All women were cytomegalovirus seroimmune at first prenatal visit. Reactivity for 2 cytomegalovirus strains was found in 14 of 40 study mothers and in 17 of 109 control mothers at first prenatal visit (P=.009). Seven of 40 (17.5%) study women and 5 of 109 (4.6%) controls (P=.002) acquired antibodies reactive with new cytomegalovirus strains during pregnancy. Evidence of infection with more than 1 strain of cytomegalovirus before or during current pregnancy occurred in 21 of 40 study mothers and 22 of 109 controls (P<.0001). CONCLUSION: Maternal reinfection by new strains of cytomegalovirus is a major source of congenital infection in this population.

Risk of Potential Drug-Drug Interactions among Brazilian Elderly A Population-Based, Cross-Sectional Study

Background: Drug-drug interactions (DDIs) are one of the main causes of adverse reactions related to medications, being responsible for up to 23% of hospital admissions. However, only a few studies have evaluated this problem in elderly Brazilians. Objectives: To determine the prevalence of potential DDIs (PDDIs) in community-dwelling elderly people in Brazil, analyse these interactions with regard to severity and clinical implications, and identify associated factors. Methods: A population-based cross-sectional study was carried out involving 2143 elderly (aged 60 years) residents of the metropolitan area of Sao Paulo, Brazil. Data were obtained from the SABE (Saude, Bem estar e Envelhecimento [Health, Well-Being, and Aging]) survey, which is a multicentre study carried out in seven countries of Latin America and the Caribbean, coordinated by the Pan-American Health Organization. PDDIs were analysed using a computerized program and categorized according to level of severity, onset, mechanism and documentation in the literature. The STATA software statistical package was used for data analysis, and logistic regression was conducted to determine whether variables were associated with PDDIs. Results: Analysis revealed that 568 (26.5%) of the elderly population included in the study were taking medications that could lead to a DDI. Almost two-thirds (64.4%) of the elderly population exposed to PDDIs were women, 50.7% were aged >= 75 years, 71.7% reported having fair or poor health and 65.8% took 2-5 medications. A total of 125 different PDDIs were identified; the treatment combination of an ACE inhibitor with a thiazide or loop diuretic (associated with hypotension) was the most frequent cause of PDDIs (n=322 patients; 56.7% of individuals with PDDIs). Analysis of the PDDIs revealed that 70.4% were of moderate severity, 64.8% were supported by good quality evidence and 56.8% were considered of delayed onset. The multivariate analysis showed that the risk of a PDDI was significantly increased among elderly individuals using six or more medications (odds ratio [OR] 3.37) and in patients with hypertension (OR 2.56), diabetes mellitus (OR 1.73) or heart problems (OR 3.36). Conclusions: Approximately one-quarter of the elderly population living in Sao Paulo could be taking two or more potentially interacting medicines. Polypharmacy predisposes elderly individuals to PDDIs. More than half of these drug combinations (57.6%, n = 72) were part of commonly employed treatment regimens and may be responsible for adverse reactions that compromise the safety of elderly individuals, especially at home. Educational initiatives are needed to avoid unnecessary risks.

Symptoms of Temporomandibular Disorders in the Population: An Epidemiological Study

Aims: To estimate the prevalence of symptoms of temporomandibular disorders (TMD) as a function of age and gender, in a representative urban sample from the Brazilian population. Methods: A total of 1,230 inhabitants (51.5% women) aged 15 to 65 years were interviewed by a validated phone survey. Sample size had been previously calculated. TMD symptoms were assessed through five questions, as recommended by the American Academy of Orofacial Pain, in an attempt to identify possible TMD. Data were derived by age and gender. Prevalence of each TMD symptom, and of combination of symptoms, was calculated. Results: At least one TMD symptom was reported by 39.2% of the individuals. Pain related to TMD was noted by 25.6% of the population. Temporomandibular joint (TMJ) sound was the most common symptom of TMD, followed by TMJ pain and masticatory muscle pain. All symptoms were more prevalent in women than in men. With men used as the reference, a relative risk (RR) of at least one TMD symptom in women was 1.31 (95% confidence interval [CI] = 1.14 to 1.52). When at least two symptoms were present, the RR was 1.93 (95% CI = 1.49 to 2.51). For three or more TMD symptoms, the RR was 2.49 (95% CI = 1.67 to 3.71). Women were also more likely than men to have TMD pain (RR = 1.78; 9% CI = 1.45 to 2.18). Conclusion: Individual symptoms, as well as a combination of TMD symptoms, are prevalent in the Brazilian urban population and are more frequent in women than in men. Additional studies should focus on risk factors for and relevance of TMD for the sufferers. J OROFAC PAIN 2010;24:270-278

Detection of Spinal Muscular Atrophy Carriers in a Sample of the Brazilian Population

Background: Spinal muscular atrophy is a common autosomal recessive neuromuscular disorder caused by mutations in the SMN1 gene. Identification of spinal muscular atrophy carriers has important implications for individuals with a family history of the disorder and for genetic counseling. The aim of this study was to determine the frequency of carriers in a sample of the nonconsanguineous Brazilian population by denaturing high-performance liquid chromatography (DHPLC). Methods: To validate the method, we initially determined the relative quantification of DHPLC in 28 affected patients (DHPLC values: 0.00) and 65 parents (DHPLC values: 0.49-0.69). Following quantification, we studied 150 unrelated nonconsanguineous healthy individuals from the general population. Results: Four of the 150 healthy individuals tested (with no family history of a neuromuscular disorder) presented a DHPLC value in the range of heterozygous carriers (0.6-0.68). Conclusions: Based on these results, we estimated there is a carrier frequency of 2.7% in the nonconsanguineous Brazilian population, which is very similar to other areas of the world where consanguineous marriage is not common. This should be considered in the process of genetic counseling and risk calculations. Copyright (C) 2011 S. Karger AG, Basel

Nocturnal awakening with headache and its relationship with sleep disorders in a population-based sample of adult inhabitants of Sao Paulo City, Brazil

Our aim was to estimate the prevalence of nocturnal awakening with headache (NAH) in the population of Sao Paulo City according to gender, age (20-80 years old) and socioeconomic classes and its relationship to sleep disorders, sleep parameters, anxiety, depression, fatigue, life quality and obesity. We used a population-based survey with a representative three-stage cluster sample. Questionnaires and scales were applied face-to-face, and polysomnography was performed in 1101 volunteers, aged 42 +/- 14 years, 55% women. The complaint of NAH occurring at least once a week had a prevalence of 8.4%, mostly in women, obese subjects and those aged 50-59 years-old. We observed associations of NAH with insomnia, restless leg syndrome (RLS), nightmares and bruxism, but not obstructive sleep apnea syndrome. In a logistics regression model, risk factors for NAH were female gender, odds ratio (OR) (95% confidence interval [CI]) 4.5 (2.8-7.3); obesity, OR 1.9 (1.1-3.3); age between 50 and 59 years, OR 2.4 (1.2-4.7); severe anxiety, OR 8.1 (3.6-18.1); RLS, 2.7 (1.2-5.6); and nightmares, 2.2 (1.3-3.7). Our study shows that NAH was highly prevalent in the population of Sao Paulo and suggests that this phenomenon has specific characteristics with specific risk factors: obesity, RLS and nightmares.