Data from: Genome-wide association study of insect bite hypersensitivity in Swedish-born Icelandic horses

Insect bite hypersensitivity (IBH) is the most common allergic skin disease in horses and is caused by biting midges, mainly of the genus Culicoides. The disease predominantly comprises a type I hypersensitivity reaction, causing severe itching and discomfort that reduce the welfare and commercial value of the horse. It is a multifactorial disorder influenced by both genetic and environmental factors, with heritability ranging from 0.16 to 0.27 in various horse breeds. The worldwide prevalence in different horse breeds ranges from 3% to 60%; it is more than 50% in Icelandic horses exported to the European continent and approximately 8% in Swedish-born Icelandic horses. To minimize the influence of environmental effects, we analyzed Swedish-born Icelandic horses to identify genomic regions that regulate susceptibility to IBH. We performed a genome-wide association (GWA) study on 104 affected and 105 unaffected Icelandic horses genotyped using Illumina® EquineSNP50 Genotyping BeadChip. Quality control and population stratification analyses were performed with the GenABEL package in R (λ = 0.81). The association analysis was performed using the Bayesian variable selection method, Bayes C, implemented in GenSel software. The highest percentage of genetic variance was explained by the windows on X chromosomes (0.51% and 0.36% by 73 and 74 mb), 17 (0.34% by 77 mb), and 18 (0.34% by 26 mb). Overlapping regions with previous GWA studies were observed on chromosomes 7, 9, and 17. The windows identified in our study on chromosomes 7, 10, and 17 harbored immune system genes and are priorities for further investigation.

昆虫叮咬超敏反应（Insect bite hypersensitivity, IBH）是马类最常见的过敏性皮肤病，主要由蠓属（Culicoides）的吸血蠓叮咬引发。该疾病以I型超敏反应为主要病理特征，会导致马匹出现严重瘙痒与不适，进而降低其动物福利与商业价值。本病属于多因素紊乱性疾病，受遗传与环境因素共同影响，在不同马品种中的遗传力范围为0.16~0.27。全球范围内不同马品种的IBH患病率介于3%~60%之间：出口至欧洲大陆的冰岛马患病率超过50%，而瑞典本土冰岛马的患病率约为8%。为尽可能降低环境因素的干扰，本研究以瑞典本土冰岛马为研究对象，旨在鉴定调控IBH易感性的基因组区域。研究共纳入104例患病冰岛马与105例健康对照个体，采用Illumina® EquineSNP50 Genotyping BeadChip芯片完成基因分型。质控与群体分层分析通过R语言中的GenABEL软件包完成（λ=0.81）。关联分析则借助GenSel软件中集成的贝叶斯变量选择方法Bayes C进行。本研究结果显示，X染色体上的两个基因组窗口（分别位于73 Mb和74 Mb处，各解释0.51%和0.36%的遗传方差）、17号染色体上位于77 Mb处的窗口（解释0.34%的遗传方差）以及18号染色体上位于26 Mb处的窗口所解释的遗传方差占比最高。本研究鉴定的基因组区域与此前多项全基因组关联（genome-wide association, GWA）研究的重叠区域位于7、9和17号染色体上。本研究在7、10和17号染色体上鉴定到的基因组窗口中携带有免疫系统相关基因，可作为后续研究的优先靶点。