S. B. Mattar

HLA-E polymorphisms in an Afro-descendant Southern Brazilian population

HLA-E is a non-classical I (Ib) gene which has limited polymorphism and low levels of tissue expression. Currently, 11 alleles are described in the literature with only three protein products. In the present study we investigated HLA-E gene variations at exons 2 and 3 and calculated allele, genotype and haplotype frequencies in a sample of 152 individuals who reported themselves as being Afro-descendants and who are voluntary bone marrow donors living in the state of Paraná, Brazil. The most frequent allele in the sample analyzed was the E(∗)01:01 (59.21%). The presence of the E(∗)01:04 allele was not detected suggesting that it has a very low worldwide frequency or that this allele may be an artifact of sequencing. We reported the most frequent alleles found as well as genotypes and haplotypes and compared our results with the few other studies found in the literature. This study is the first to investigate Afro-descendants from the South of Brazil.

A novel allele, HLA‐A*66:14, identified in a Brazilian volunteer bone marrow donor

The new allele might have arisen from HLA-A*66:01 through a point mutation at codon 182.1 (ACG→GCG) resulting in a non-conservative change from threonine to alanine.

Two novel alleles, HLA-B*40:125 and B*40:129, in the Brazilian population

The new alleles, HLA-B*40:125 and HLA-B*40:129, present a mismatch at codon 103.1 (G → C) and three mismatches at codons 9.1 (C → T), 11.1 (T → G) and 12.1 (G → A).

HLA-DRB1*08:48, a novel allele identified in a Brazilian donor

The new allele presents a point mutation at codon 67.1 (ATC→CTC) resulting in a conservative change from isoleucine to leucine.

Identification of a new HLA‐DRB1*11 variant, HLA‐DRB1*11:130, by sequence‐based typing in a Brazilian individual

HLA-DRB1*11:130, detected in a Euro-Brazilian female, presents a point mutation at codon 59.3 (GAG→GAC).

HLA-B*18:35, a new HLA-B*18 allele identified by sequence-based typing in a Brazilian volunteer bone marrow donor

A novel human leukocyte antigen-B allele named B*18:35 was identified in a Brazilian volunteer bone marrow donor.

A new allele, HLA-B*4212, identified in a Brazilian volunteer bone marrow donors by sequence-based typing.

Here we report the discovery of a novel HLA‐B allele, named B*4212 in a Brazilian volunteer bone marrow donor. The new sequence has nucleotide variation at position 496 (T→G) as compared with B*4201. This variation results in a conservative amino acid substitution from valine to glycine at codon 165 of exon 3.

HLA-G 5' URR SNPs and 3' UTR 14-bp insertion/deletion polymorphism in an Afro-Brazilian population from Paraná State.

The present study investigated 23 SNPs in the 5′URR promoter region and the 14 bp ins/del polymorphism at the 3′UTR region of the HLA‐G gene in 150 individuals with Afro‐Brazilian ancestry. Three haplotypes were found to be the most frequent. Comparing these polymorphisms in other samples, our data suggest that Afro‐Brazilians are more similar to the Euro‐Brazilians than to Hutterite population.

HLA‐F polymorphisms in a Euro‐Brazilian population from Southern Brazil

HLA-F is a non-classical major histocompatibility complex (MHC) gene. It codes class Ib MHC molecules with restricted distribution and less nucleotide variations than MHC class Ia genes. Of the 22 alleles registered on the IMGT database only four alleles encode for proteins that differ in their primary structure. To estimate genotype and allele frequencies, this study targeted on known protein coding regions of the HLA-F gene. Genotyping was performed by Sequence Base Typing (SBT). The sample was composed by 199-unrelated bone marrow donors from the Brazilian Bone Marrow Donor Registry (REDOME), Euro-Brazilians, from Southern Brazil. About 1673 bp were analyzed. The most frequent allele was HLA-F*01:01 (87.19%), followed by HLA-F*01:03 (12.31%), HLA-F*01:02 (0.25%) and HLA-F*01:04 (0.25%). Significant linkage disequilibrium (LD) was verified between HLA-F and HLA classes I and II alleles. This is the first study regarding HLA-F polymorphisms in a Euro-Brazilian population contributing to the Southern Brazilian genetic characterization.

Identification of a novel HLA-A allele, HLA-A*0355, in a Brazilian family of eastern European descendents

The new human leukocyte antigen (HLA) class I allele, HLA-A*0355 was identified in a Brazilian family. Our sequence analysis detected a mismatch located in exon 2, codon 86, at position 258 (C-->A) that results in a nonsilent and nonconservative substitution with the replacement of asparagine by lysine. Substitutions located at this oligosaccharide attachment site of the protein were observed in only other four classic HLA class I sequences, indicating a highly conserved peptide site however its function remains unknown.