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- HLA polymorphysms in Forros and Angolares from São Tomé Island (West Africa): evidence for the population originPublication . Saldanha, Nádia; Spínola, Carla; Santos, Margarida R.; Simões, Joaquim P.; Bruges-Armas, Jácome; Brehm, António; Spínola, Hélder
- HLA-DQA1 and HLA-DQB1 allele diversity and its extended haplotypes in Madeira Island (Portugal)Publication . Spínola, H.; Lemos, A.; Couto, A. R.; Parreira, B.; Soares, M.; Dutra, I.; Bruges-Armas, J.; Brehm, A.This study shows, for the first time, high-resolution allele frequencies of HLA-DQA1 loci in Madeira Island (Portugal) and allows us to better understand and refine present knowledge on DQB1 variation, with the identification of several alleles not previously reported in this population. Estimates on haplotype profile, involving HLA-A, HLA-B, HLADRB1, HLA-DQA1 and HLA-DQB1, are also reported.
- HLA‐A polymorphisms in four ethnic groups from Guinea‐Bissau (West Africa) inferred from sequence‐based typingPublication . Spínola, C.; Bruges-Armas, J.; Brehm, A.; Spínola, H.Human leukocyte antigen (HLA)-A locus polymorphisms were examined at highresolution level, using sequence-based typing, in the four most representative Guinea-Bissau(NorthwestAfrica)ethnicgroups:Balanta,Bijago´ s,FulaandPapel. DespitetheFulagrouphavingsignificantdifferenceswhencomparedwiththeother three ethnic groups, all four groups most likely received a genetic input from non sub-Saharans. The Bijago´ s and Papel groups showed similarities to neighboring populations from Mali and Senegal. The Balanta, despite their oral tradition of an East Africa origin, show affinities to Cameroon populations, highly influenced by Bantu migrations. These results are congruent with historical sources and other genetic studies that support the finding that the Guinea-Bissau genetic pool was influenced by several migrations from North Africa, Sahara and East Africa.
- HLA polymorphisms in Cabo Verde and Guiné-Bissau inferred from sequence-based typingPublication . Spínola, Hélder; Bruges-Armas, Jácome; Middleton, Derek; Brehm, AntónioHuman leukocyte antigen (HLA)-A, -B, and -DRB1 polymorphisms were examined in the Cabo Verde and Guiné-Bissau populations. The data were obtained at high-resolution level, using sequence-based typing. The most frequent alleles in each locus was: A*020101 (16.7% in Guiné-Bissau and 13.5% in Cabo Verde), B*350101 (14.4% in Guiné-Bissau and 13.2% in Cabo Verde), DRB1*1304 (19.6% in Guiné-Bissau), and DRB1*1101 (10.1% in Cabo Verde). The predominant three loci haplotype in Guiné-Bissau was A*2301-B*1503-DRB1*1101 (4.6%) and in Cabo Verde was A*3002-B*350101-DRB1*1001 (2.8%), exclusive to northwestern islands (5.6%) and absent in Guiné-Bissau. The present study corroborates historic sources and other genetic studies that say Cabo Verde were populated not only by Africans but also by Europeans. Haplotypes and dendrogram analysis shows a Caucasian genetic influence in today’s gene pool of Cabo Verdeans. Haplotypes and allele frequencies present a differential distribution between southeastern and northwestern Cabo Verde islands, which could be the result of different genetic influences, founder effect, or bottlenecks. Dendrograms and principal coordinates analysis show that Guineans are more similar to North Africans than other HLA-studied sub-Saharans, probably from ancient and recent genetic contacts with other peoples, namely East Africans.
- HLA genes in Madeira Island (Portugal) inferred from sequence-based typing: footprints from different originsPublication . Spínola, Hélder; Bruges-Armas, Jácome; Mora, Marian Gantes; Middleton, Derek; Brehm, AntónioHuman leukocyte antigen (HLA)-A, HLA-B, and HLA-DRB1 polymorphisms were examined in Madeira Island populations. The data was obtained at high-resolution level, using sequence-based typing (SBT). The most frequent alleles at each loci were: A*020101 (24.6%), B*5101 (9.7%), B*440201 (9.2%), and DRB1*070101 (15.7%). The predominant three-loci haplotypes in Madeira were A*020101–B*510101–DRB1*130101 (2.7%) and A*010101–B*0801–DRB1*030101 (2.4%), previously found in north and central Portugal. The present study corroborates historical sources and other genetic studies that say Madeira were populated not only by Europeans, mostly Portuguese, but also sub-Saharan Africans due to slave trade. Comparison with other populations shows that Madeira experienced a stronger African influence due to slave trade than Portugal mainland and even the Azores archipelago. Despite this African genetic input, haplotype and allele frequencies were predominantly from European origin, mostly common to mainland Portugal.
- HLA Class-I diversity in Cameroon: evidence for a North-South structure of genetic variation and relationships with african populationsPublication . Spínola, Hélder; Couto, Ana Rita; Peixoto, Maria José; Anagnostou, Paolo; Destro-Bisol, Giovanni; Spedini, Gabriella; Lopéz-Larrea, Carlos; Bruges-Armas, JácomeHLA class I diversity (loci A, B and C) was analysed in four populations, two from North Cameroon (Podokwo and Uldeme) and two from South Cameroon (Ewondo and Bamileke). Northern and southern Cameroon populations show a substantial genetic diversity in terms of haplotype sharing and genetic distances, even despite the low percentage of variance due to differences among populations evidenced by analysis of molecular variance. The signals of differentiation among populations are consistent with their linguistic affiliation, and support previous evidence, based on autosomal microsatellites and protein loci, which has shown that the complex pattern of genetic variation of Cameroon can in part be described by contrasting the northern and southern part of the country. Looking at our results in the more general framework of HLA diversity in sub-Saharan Africa, it turns out that the Podokwo and Uldeme show some genetic links to populations of the southern western branch of the Sahel corridor, while their high frequency of A∗02 and C∗04 alleles is congruent with previously hypothesised introgression of non-sub-Saharan alleles. On the other hand, signals of shared ancestry between the Bamileke and Ewondo and the Bantu speakers from central and southern Africa were detected.
- Discrepancies in HLA Typing by PCR-SSOP and SBT Techniques: a case studyPublication . Spínola, Hélder; Bruges-Armas, Jácome; Brehm, AntónioSix hundred twenty-one samples from Portugal, the Cabo Verde archipelago, and Guinea-Bissau were typed for HLA-A, HLA-B, and HLADRB1usingthepolymerasechainreaction–sequence-specificoligonucleotide probe (PCR-SSOP) method and the sequence-based typing (SBT) method to characterizeandcomparediscrepanciesbetweenthetwomethods.Fifty-three alleles (4.27% of 1,242 chromosomes typed) identified by the PCR-SSOP method were not concordant with the results obtained using the SBT method. Thirty-four (2.74% of total chromosomes typed) PCR-SSOP mistyping results were discrepancies inside the same allele group and 19 others (1.53% of total chromosomes typed) were relative to nonconcordant results between different groups. PCR-SSOP allele mistyping is the result of interpretation difficulties resulting from less intense, absent, or dubious hybridization patterns. Noncommercial PCR-SSOP procedures are highly exigent on the technicians’ experience and the availability of properly calibrated high-precision equipment.
- HLA class I and II polymorphisms in Azores show different settlements in Oriental and Central islandsPublication . Spínola, H.; Brehm, A.; Bettencourt, B.; Middleton, D.; Bruges-Armas, J.Human leucocyte antigen-A, -B, -Cw, -DRB1, -DQA1 and -DQB1 polymorphisms were examined in the Azorean population. The data were obtained at high-resolution level, using polymerase chain reaction (PCR) with sequence-specific primer, PCR-sequence-specific oligonucleotides and sequence-based typing. The most frequent allele in each locus was: A*0201 (24.5%), B*510101 (9.8%), Cw*0401 (14.8%), DRB1*070101 (18.3%), DQA1*0201 (17.4%) and DQB1*0301 (19.4%). The predominant extended haplotype was A*0202-B*1503-Cw*0202-DRB1*090102-DQA1*0303-DQB1*0202 (1.9%), which was found to be absent in the Portuguese mainland. The present study corroborates historical sources that say the Azores were populated not only by Portuguese but also by other Europeans, mostly Flemish people. Despite dendrogram analysis showing some remote Asian genetic affinities, the lack of specific alleles and haplotypes from those populations does not allow us to conclude for direct influence. Haplotype and allele frequencies in Azores show no homogeneous distribution between Oriental and Central islands of this archipelago. The Oriental islands harbour several haplotypes already found in mainland Portugal and identified as Mediterranean and European. The Central group of islands on the contrary clearly shows an influence of north Europeans (most probably derived from a well-documented Flemish settlement), with much less affinity to mainland Portugal.
- Polimorfismo do alelo HLA-B27 no desenvolvimento das espondilartropatiasPublication . Peixoto, M. J.; Gonzales, T.; Spínola, Hélder; Couto, A. R.; Gantes Mora, M.; Brehm, António; Santos, M. R.; Garrett, F.; Bruges-Armas, J.A associação da molécula HLA-B27 com a espondilite anquilosante (AS) e outras espondilartropatias (SpA), permanece como uma das mais fortes verificada entre moléculas HLA e doenças humanas. Desde que foi descrita, em 1973, tem sido alvo de intensa investigação na tentativa de compreender o mecanismo patogénico que lhe está subjacente. Este artigo tem como objectivo fazer uma revisão dos conhecimentos actuais relativos à estrutura e polimorfismo da molécula HLA-B27, bem como descrever os modelos propostos para explicar o seu papel no desenvolvimento das espondilartropatias.
- Evaluation of two methods for computational HLA haplotypes inference using a real datasetPublication . Bettencourt, Bruno F.; Santos, Margarida R.; Fialho, Raquel N.; Couto, Ana R.; Peixoto, Maria J.; Pinheiro, João P.; Spínola, Hélder; Mora, Marian G.; Santos, Cristina; Brehm, António; Bruges-Armas, Jácome