Work

GERBase: an online tool for high-resolution HLA allele and haplotype frequencies and linkage disequilibrium analysis in a Brazilian population

Year: 2026

Type: article

Abstract: GERBase is a web tool that provides family-phased, high-resolution Human Leukocyte Antigen (HLA) allele and haplotype frequencies together with linkage disequilibrium (LD) metrics. The tool supports haplotype blocks defined by the user's query, as well as stratification by self-reported race or visualization of the total admixed population. For analysis, HLA alleles were grouped by antigen recognition domain (ARD), while the web tool retained the ability to discriminate between alleles within the same group. The database contains 17,260 haplotypes from unrelated candidates for hematopoietic cell or kidney transplantation, typed at IGEN (São Paulo, Brazil), phased by segregation analysis in family studies rather than statistically inferred; 9,026 haplotypes (52.3%) are phased across all nine classical loci, and the remainder across at least two. Allele frequencies in GERBase closely track those reported for the Brazilian donor registry in the Common, Intermediate, and Well-Documented (CIWD)-Brazil catalog (r = 0.9988; P < 0.0001 across 238 alleles). This tool can be used in the daily practice of HLA laboratories, including the investigation of allele dropout, the optimization of virtual crossmatching when donor HLA typing is incomplete, and the enhancement of donor prioritization for allogeneic hematopoietic cell transplantation. GERBase is available at https://www.igen.org.br/gerbase/, does not require registration and is free to use.

Source: Frontiers in Genetics

DOI: 10.3389/fgene.2026.1973772