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Tackling the itch: GWAS on insect bite hypersensitivity using IgE levels in two horse populations

Francois, Liesbeth; Velie, Brandon; Lindgren, Gabriella; Schurink, A.


The most common skin allergy in horses, insect bite hypersensitivity (IBH), is mainly caused by bites of Culicoides spp. In the Netherlands, Culicoides obsoletus is the most important species involved in the development of IBH. The welfare of allergic horses is reduced as they suffer from severe itch and sometimes secondary infections as a result of self-mutilation in an attempt to relieve the itch. Unt il now, genomic studies have shown regions of interest in several horse breeds but the exact genetic cause of this widespread disease has yet to be identified. While most studies use case/control status or severity scores, we use the IgE levels against C. obsoletus whole body extract and seven recombinant C. obsoletus allergens. The aim is to improve identification of genomic regions and validate previously reported regions. In this study we performed a genome wide association study (GWAS) using IgE levels as phenotypes in Shetland ponies (200 horses) and Icelandic horses (146 horses). The horses were sampled using a matched case/control design and genotyped on the Illumina 70K SNP chip. Serum IgE levels determined by ELISA were available as well as additional information concerning sex, age at sampling, coat colour, and year and month of sampling. GWAS was performed using the GenABEL package in R and the results showed a clear association between a region on ECA20 and IgE levels in Shetland ponies. This region has consistently been reported in former studies with the ELA region as a possible candidate gene. These results are a step closer towards identifying genes involved in IBH and the development of genomic tools to decrease IBH prevalence.

Publicerad i

Annual meeting of the European Association for Animal Production
2016, nummer: 22, sidor: 395-395 Titel: Book of Abstracts of the 67th Annual Meeting of the European Federation of Animal Science
ISBN: 978-90-8686-284-9, eISBN: 978-90-8686-830-8
Utgivare: Wageningen Academic Publishers


67th Annual Meeting of the European Federation of Animal Science