Region 1p13.2 including the RSBN1, PTPN22, AP4B1 and long non‐coding RNA genes does not bear risk factors for endemic pemphigus foliaceus (fogo selvagem)

Abstract Pemphigus foliaceus (PF) is an autoimmune skin disease characterized by autoantibodies directed mainly against desmoglein‐1. The purpose of this study was to determine whether differential susceptibility to endemic PF in Brazil ( fogo selvagem ) is associated with polymorphisms at the cytogenetic location 1p13.2. Four single nucleotide polymorphisms that together tag 28 SNPs on a segment of approximately 312,000 bp encompassing the protein‐coding genes MAGI3, PHTF1, RSBN1, PTPN22, BCL2L15, AP4B1, DCLRE1B , the pseudogenes MTND5P20, RPS2P14 (AL133517.1) and the long non‐coding RNA genes AL137856.1, and AP4B1‐AS1 were used as markers for association analysis in a case–control study. Allele, genotype and haplotype frequencies of rs33996649 , rs2476601 , rs3789604 and rs3195954 were compared between patient and control samples. No significant association was found. Lack of association with rs2476601 of the PTPN22 gene agrees with previous results for pemphigus vulgaris and the Tunisian form of endemic pemphigus foliaceus. The other three SNPs had never been analysed before in any form of pemphigus. We conclude that variants in structural and regulatory sites of region 1p13.2 are not susceptibility factors for fogo selvagem . We suggest careful investigation of this genomic region in diseases that had been previously associated with PTPN22 , since there are several other genes relevant for immune‐mediated diseases located in 1p13.2.