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- 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 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.
- 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
- Human leucocyte antigens class II allele and haplotype association with Type 1 Diabetes in Madeira Island (Portugal)Publication . Spínola, H.; Lemos, A.; Couto, A. R.; Parreira, A.; Soares, M.; Dutra, I.; Bruges-Armas, J.; Brehm, A.; Abreu, S.This study confirms for Madeira Island (Portugal) population the Type 1 Diabetes (T1D) susceptible and protective Human leucocyte antigens (HLA) markers previously reported in other populations and adds some local specificities. Among the strongest T1D HLA associations, stands out, as susceptible, the alleles DRB1*04:05 (OR = 7.3), DQB1*03:02 (OR = 6.1) and DQA1*03:03 (OR = 4.5), as well as the haplotypes DRB1*04:05- DQA1*03:03- DQB1*03:02 (OR = 100.9) and DRB1*04:04- DQA1*03:01- DQB1*03:02 (OR = 22.1), and DQB1*06:02 (OR = 0.07) and DRB1*15:01- DQA1*01:02- DQB1*06:02 (OR = 0.04) as protective. HLA- DQA1 positive for Arginine at position 52 (Arg52) (OR = 15.2) and HLA- DQB1 negative for Aspartic acid at the position 57 (Asp57) (OR = 9.0) alleles appear to be important genetic markers for T1D susceptibility, with higher odds ratio values than any single allele and than most of the haplotypes. Genotypes generated by the association of markers Arg52 DQA1 positive and Asp57 DQB1 negative increase T1D susceptibility much more than one would expected by a simple additive effect of those markers separately (OR = 26.9). This study also confirms an increased risk for DRB1*04/DRB1*03 heterozygote genotypes (OR = 16.8) and also a DRB1*04- DQA1*03:01- DQB1*03:02 haplotype susceptibility dependent on the DRB1*04 allele (DRB1*04:01, OR = 7.9; DRB1*04:02, OR = 3.2; DRB1*04:04, OR = 22.1).