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African Ancestry (african + ancestry)
Selected AbstractsNeuropsychiatric movement disorders following streptococcal infectionDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 11 2005K G Walker MB BS The aim of this study was to describe post-streptococcal movement disorders that form part of the acute rheumatic fever complex. The clinical records of patients diagnosed with Sydenham's chorea were analyzed retrospectively to investigate epidemiology, the significance of socioeconomic deprivation, clinical manifestations, treatments, outcomes, long-term morbidity, and disease evolution. Forty-two patients (21 males, 21 females) were diagnosed with Sydenham's chorea. The median presentation age was 9 years 8 months (range 3y 5mo to 13y 2mo). Nineteen patients were of indigenous African ancestry; 23 were of mixed ancestry. All patients lived in poverty and had poor access to medical care. Twelve of the total group had disabling symptoms for longer than 2 years; six of these patients developed paediatric autoimmune neuropsychiatric disorder associated with Streptococcus (Paediatric autoimmune neuropsychiatric disorder associated with Streptococcus [PANDAS]), five Tourette syndrome (TS), and one learning difficulties. Poor outcome was significantly more prevalent in patients of mixed ancestry, in those with a positive family history, previous behavioural problems, or a failure to complete 10 days of penicillin and ,bed-rest'/hospitalization. Sydenham's chorea is one manifestation of post-streptococcal neuropsychiatric movement disorders. This study demonstrates that patients can present with one diagnosis and evolve other neuropsychiatric conditions such as TS and PANDAS. In the South African context, it is important to delineate neuropsychiatric movement disorders associated with streptococcal infections. The potential genetic susceptibility should be explored. [source] Polymorphisms in the thymidylate synthase promoter and the DNA repair genes XRCC1 and XPD in a Brazilian populationENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 9 2006Renata Canalle Abstract Polymorphisms in genes responsible for maintaining genomic integrity are potential modifiers of disease risk. Since considerable interindividual and interethnic variation in DNA repair capacity has been associated with polymorphic alleles, we evaluated the frequency of the 2R/3R variants in the TS promoter, Arg194Trp and Arg399Gln in the XRCC1 gene, and Asp312Asn and Lys751Gln in the XPD gene in 364 healthy individuals from a Brazilian population separated by ethnicity (European ancestry and African ancestry). The genotypes were determined by PCR (TS) or by PCR-RFLP (XRCC1 and XPD). The frequency of the TS 3R allele was 0.56 for whites and 0.51 for nonwhites. In the case of the XRCC1 MspI polymorphism, the allele frequencies were 0.09 for 194Trp in both nonwhites and whites and 0.27 and 0.28 for 399Gln in nonwhites and whites, respectively. For the XPD 312Asn allele, we found a frequency of 0.25 in white individuals, which was significantly different (P = 0.025) from that seen in nonwhites (0.15). Similarly, the 751Gln polymorphic allele of the XPD gene was significantly more frequent (P < 0.002) in whites (0.30) than in nonwhites (0.20). The genotype frequencies were within Hardy,Weinberg equilibrium. We concluded that the genotype and allele frequencies of XPD gene polymorphism differed between white and nonwhite Brazilians, and that the frequencies of the XPD 312Asn and XRCC1 399Gln alleles in this Brazilian population showed ethnic variability when compared with those observed in other populations. Environ. Mol. Mutagen., 2006. © 2006 Wiley-Liss, Inc. [source] ADH1B*3 and Response to Alcohol in African-AmericansALCOHOLISM, Issue 7 2010Denis M. McCarthy Background: Variations in the alleles for the alcohol-metabolizing enzymes have been shown to influence risk for alcohol dependence. One variant, ADH1B*3, is observed almost exclusively in populations of African ancestry and has been shown to be associated with reduced rates of alcohol dependence. We conducted an alcohol challenge study to test whether ADH1B*3 is associated with differences in subjective and physiological response to alcohol. Method: We administered a moderate dose of alcohol (0.72 g/kg for males, 0.65 g/kg for females) to a sample of African-American young adults (n = 91; ages 21 to 26). Participants were genotyped for ADH1B, as well as additional polymorphisms that might contribute to alcohol response. Breath alcohol concentration, self-reported sedation and stimulation, and pulse rate were assessed prior to alcohol administration and for 2.5 hours following administration. Results: ADH1B*3 was associated with higher levels of sedation and a sharper increase in pulse rate immediately following alcohol consumption. Conclusions: These findings suggest that the lower rates of alcohol dependence in those with ADH1B*3 alleles may be because of differences in alcohol response, particularly increased sedation. [source] Sexuality, Color, and Stigma among Northeast Brazilian WomenMEDICAL ANTHROPOLOGY QUARTERLY, Issue 2 2004L. A. REBHUN Despite its international image as a sexually free-spirited country, local attitudes toward morality of sexual behavior remain complex throughout Brazil, especially in rural areas and the conservative Northeast region. In addition, notwithstanding its official ideology of nonracism, African ancestry as judged through personal appearance (color) constitutes a significant social and economic disadvantage. Using Goffman's idea of "spoiled identity" as a starting point, I show how locals use sexual behavior as a multivocal symbol of moral status in women, and how spoiled sexual reputation interacts with other stigmatized statuses, especially color. I also consider how the acquisition of sexually stigmatized status jeopardizes women's well-being and that of their children. [Brazil, color, gender, sexuality, stigma, women] [source] Genetics and Asthma Disease Susceptibility in the US Latino PopulationMOUNT SINAI JOURNAL OF MEDICINE: A JOURNAL OF PERSONALIZED AND TRANSLATIONAL MEDICINE, Issue 2 2010Joan Reibman MD Abstract The US Latino population is heterogeneous with diversity in environmental exposures and socioeconomic status. Moreover, the US Hispanic population derives from numerous countries previously under Spanish rule, and many Hispanics have complex proportions of European, Native American, and African ancestry. Disparities in asthma severity and control are due to complex interactions between environmental exposures, socioeconomic factors, and genetic variations. In addition, diseases within the Latino community may also differ by country of origin. Although US Census data show low asthma rates in the Hispanic population as a whole, there is a lot of variability in the prevalence and morbidity of asthma, with a prevalence of 5.0% in Mexican Americans versus 17.0% in Puerto Ricans. The diversity and population admixture make the study of the genetics of asthma complex in Latino populations. However, an understanding of the genetics of asthma in all populations, including the Latino population, can enhance risk identification, help us to target pharmacological therapy, and guide environmental regulations, all of which can promote a reduction in health disparities. The inclusion of markers of ancestral diversity and the incorporation of techniques to adjust for stratification now make these studies feasible in complex populations, including the Latino population. To date, studies using linkage analyses, genome-wide associations, or candidate gene analyses have identified an association of asthma or asthma-related phenotypes with candidate genes, including interleukin 13, ,-2 adrenergic receptor, a disintegrin and metalloproteinase 33, orosomucoid 1-like 3, and thymic stromal lymphopoietin. As reviewed here, although these genes have been identified in diverse populations, limited studies have been performed in Latino populations, and they have had variable replication. There is a need for the development of registries with well-phenotyped pediatric and adult Latino populations and subgroups for inclusion in the rapidly expanding field of genetic studies, and these studies need to be used to reduce health disparities. Mt Sinai J Med 77:140,148, 2010. © 2010 Mount Sinai School of Medicine [source] Is There a Genetic Basis for Health Disparities in Human Immunodeficiency Virus Disease?MOUNT SINAI JOURNAL OF MEDICINE: A JOURNAL OF PERSONALIZED AND TRANSLATIONAL MEDICINE, Issue 2 2010Cheryl Winkler PhD Abstract The highest global prevalence rates for human immunodeficiency virus and acquired immune deficiency syndrome have been recorded in southern Africa; in the United States, individuals of African descent are disproportionately affected by human immunodeficiency virus infection. Human immunodeficiency virus,infected individuals with African ancestry are also estimated to have a 17-fold or greater risk for developing human immunodeficiency virus,associated nephropathy in comparison with their counterparts of non-African descent. Several recent studies have implicated genetic alleles that are more frequent in populations of African descent and increase the risk of human immunodeficiency virus infection and the risk of human immunodeficiency virus,associated neuropathy (HIVAN). The supposition that persons of African descent are more susceptible to human immunodeficiency virus infection because of an underlying genetic predisposition is not supported by available evidence. However, strong, replicated data show that the increased risk for human immunodeficiency virus,associated nephropathy, as well as other major forms of kidney disease in individuals of African descent, is due in part to MYH9 (myosin, heavy chain 9, non-muscle) renal disease susceptibility alleles that are very frequent throughout sub-Saharan Africa but are infrequent or absent in non-Africans. Selection, drift, and demographic events shape the allelic architecture of the human genome: it is expected that these events will be reflected in geographic-specific differentiation in allele frequencies for a small subset of alleles that may be associated with either increased or reduced risk for complex and infectious diseases. Mt Sinai J Med 77:149,159, 2010. © 2010 Mount Sinai School of Medicine [source] A South African mixed ancestry family with Huntington disease-like 2: Clinical and genetic featuresMOVEMENT DISORDERS, Issue 14 2007Soraya Bardien PhD Abstract Huntington disease-like 2 (HDL2) is a neurodegenerative disorder caused by an expansion of a CTG repeat in the junctophilin-3 gene (JPH3). A limited number of HDL2 families have been reported, all of apparently Black African ancestry. We report on a South African family that presented with progressive dementia and a movement disorder affecting numerous family members. Genotyping of the JPH3 CTG repeat revealed pathogenic expansions in three affected individuals. Whereas HDL2 is thought to be clinically indistinguishable from Huntington disease (HD), 2 of the patients in this study presented with clinical symptoms that differed substantially from HD; one had myoclonus and the other had Parkinsonism. Moreover, brain magnetic resonance imaging scans of these patients showed imaging features atypical for HD. Mitochondrial DNA and Y-chromosome DNA analysis on a family member showed that his maternal and paternal ancestries are typical of that found among the South African mixed ancestry or colored population. A difference in the distribution of CTG repeats between Caucasian and Black individuals was detected. We conclude that the phenotype of HDL2 is broad and can differ from that of typical HD. The diagnosis therefore should be considered in a wide spectrum of neuropsychiatric and abnormal movement presentations. © 2007 Movement Disorder Society [source] Maximum likelihood estimates of admixture in northeastern Mexico using 13 short tandem repeat lociAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 4 2002Ricardo M. Cerda-Flores Tetrameric short tandem repeat (STR) polymorphisms are widely used in population genetics, molecular evolution, gene mapping and linkage analysis, paternity tests, forensic analysis, and medical applications. This article provides allelic distributions of the STR loci D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820, CSF1PO, TPOX, TH01, and D16S539 in 143 Mestizos from Northeastern Mexico, estimates of contributions of genes of European (Spanish), American Indian and African origin in the gene pool of this admixed Mestizo population (using 10 of these loci); and a comparison of the genetic admixture of this population with the previously reported two polymorphic molecular markers, D1S80 and HLA-DQA1 (n = 103). Genotype distributions were in agreement with Hardy-Weinberg expectations (HWE) for almost all 13 STR markers. Maximum likelihood estimates of admixture components yield a trihybrid model with Spanish, Amerindian, and African ancestry with the admixture proportions: 54.99% ± 3.44, 39.99% ± 2.57, and 5.02% ± 2.82, respectively. These estimates were not significantly different from those obtained using D1S80 and HLA-DQA1 loci (59.99% ± 5.94, 36.99% ± 5.04, and 3.02% ± 2.76). In conclusion, Mestizos of Northeastern Mexico showed a similar ancestral contribution independent of the markers used for evolutionary purposes. Further validation of this database supports the use of the 13 STR loci along with D1S80 and HLA-DQA1 as a battery of efficient DNA forensic markers in Northeastern Mestizo populations of Mexico. Am. J. Hum. Biol. 14:429,439, 2002. © 2002 Wiley-Liss, Inc. [source] Brief communication: Admixture analysis with forensic microsatellites in Minas Gerais, Brazil: The ongoing evolution of the capital and of an African-derived communityAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2009Marília O. Scliar Abstract We report the estimated allele frequencies for 13 and 14 microsatellite loci in two populations of Minas Gerais, Brazil as follows: Belo Horizonte (the capital) and Marinhos (an African-derived community). Analysis of the African, Amerindian, and European genetic contributions to both populations, together with historical information, revealed distinct differences between the two populations. Estimates for Belo Horizonte revealed a higher-European (66%) than African (32%) contribution, and a minimal Amerindian contribution. These results are consistent with the peopling of the city mainly by people from the Minas Gerais hinterland, a people highly admixed but with more European ancestry. Estimates for Marinhos confirmed the high-African component of the population. However, a temporal analysis of two datasets,CURRENT (representing the population living in Marinhos today) and ORIGINAL (representing families, who have lived in Marinhos since the onset of the 20th century),,identified a diminishing of the population's African ancestry from 92% in the ORIGINAL group to 67% in the CURRENT group. This change is here interpreted as a consequence of the growing migration into the village of people with more European ancestry and subsequent admixture with the local population. Am J Phys Anthropol, 2009. © 2009 Wiley-Liss, Inc. [source] Ecogeographic variation in human nasal passagesAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2009Todd R. Yokley Abstract Theoretically, individuals whose ancestors evolved in cold and/or dry climates should have greater nasal mucosal surface area relative to air volume of the nasal passages than individuals whose ancestors evolved in warm, humid climates. A high surface-area-to-volume (SA/V) ratio allows relatively more air to come in contact with the mucosa and facilitates more efficient heat and moisture exchange during inspiration and expiration, which would be adaptive in a cold, dry environment. Conversely, a low SA/V ratio is not as efficient at recapturing heat and moisture during expiration and allows for better heat dissipation, which would be adaptive in a warm, humid environment. To test this hypothesis, cross-sectional measurements of the nasal passages that reflect surface area and volume were collected from a sample of CT scans of patients of European and African ancestry. Results indicate that individuals of European descent do have higher SA/V ratios than individuals of African descent, but only when decongested. Otherwise, the two groups show little difference. This pattern of variation may be due to selection for different SA/V configurations during times of physical exertion, which has been shown to elicit decongestion. Relationships between linear measurements of the skeletal nasal aperture and cavity and cross-sectional dimensions were also examined. Contrary to predictions, the nasal index, the ratio of nasal breadth to nasal height, is not strongly correlated with internal dimensions. However, differences between the nasal indices of the two groups are highly significant. These results may be indicative of different adaptive solutions to the same problem. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc. [source] Shipwrecks and founder effects: Divergent demographic histories reflected in Caribbean mtDNAAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2005Antonio Salas Abstract During the period of the Atlantic slave trade (15th,19th centuries), millions of people were forced to move from Africa to many American destinations, changing dramatically the human landscape of the Americas. Here, we analyze mitochondrial DNA from two different American populations with African ancestry, with hitherto unknown European and Native American components. On the basis of historical records, African-Americans from Chocó (Colombia) and the Garífunas (or "Black Carib") of Honduras are likely to have had very different demographic histories, with a significant founder effect in the formation of the latter. Both the common features and differences are reflected in their mtDNA composition. Both show a minor component (,16%) from Native Central/South Americans and a larger component (,84%) from sub-Saharan Africans. The latter component is very diverse in the African-Americans from Chocó, similar to that of sub-Saharan Africans, but much less so in the Garífunas, with several mtDNA types elevated to high frequency, suggesting the action of genetic drift. Am J Phys Anthropol, 2005. © 2005 Wiley-Liss, Inc. [source] Huntington's disease,like 2 (HDL2) in North America and JapanANNALS OF NEUROLOGY, Issue 5 2004Russell L. Margolis MD Huntington's Disease,like 2 (HDL2) is a progressive, autosomal dominant, neurodegenerative disorder with marked clinical and pathological similarities to Huntington's disease (HD). The causal mutation is a CTG/CAG expansion mutation on chromosome 16q24.3, in a variably spliced exon of junctophilin-3. The frequency of HDL2 was determined in nine independent series of patients referred for HD testing or selected for the presence of an HD-like phenotype in North America or Japan. The repeat length, ancestry, and age of onset of all North American HDL2 cases were determined. The results show that HDL2 is very rare, with a frequency of 0 to 15% among patients in the nine case series with an HD-like presentation who do not have the HD mutation. HDL2 is predominantly, and perhaps exclusively, found in individuals of African ancestry. Repeat expansions ranged from 44 to 57 triplets, with length instability in maternal transmission detected in a repeat of 33 triplets. A younger age of onset is correlated with a longer repeat length (r2 = 0.29, p = 0.0098). The results further support the evidence that the repeat expansion at the chromosome 16q24.3 locus is the direct cause of HDL2 and provide preliminary guidelines for the genetic testing of patients with an HD-like phenotype. Ann Neurol 2004 An Erratum has been published for this article in Ann Neurol 56: 911, 2004. [source] | |||||||||||||