Valberg S J, Geyer C, Sorum S A, Cardinet G H
Department of Clinical and Population Sciences, College of Veterinary Medicine, University of Minnesota, St Paul 55108, USA.
Am J Vet Res. 1996 Mar;57(3):286-90.
To trace pedigrees from affected horses, identify likely contributing founder horses, and determine the conditional probability of founder genotypes.
Muscle biopsy records from the Neuromuscular Disease Laboratory at the University of California-Davis and the University of Minnesota were searched to identify horses with a polysaccharide storage myopathy and exercise intolerance/rhabdomyolysis. Pedigrees containing 5 to 6 generations were obtained where possible.
13 Quarter Horses, 4 American Paint Horses, 3 Appaloosas, and 3 Quarter Horse crossbreds (16 mares, 4 geldings, and 3 stallions) were identified with polysaccharide storage myopathy. Pedigrees were available for 18 horses.
Inbreeding coefficients, founder contributions, and conditional probability of founder genotypes were calculated.
Three stallions (A, B, and C) were featured prominently in the pedigrees. Stallions A and B descended from a common sire. On average, A contributed 8.8% (range, 0 to 23%) of the genes in affected horses, B contributed 4.2% (range, 0 to 14%), and C contributed 3.0% (range, 0 to 14%). The sire and dam of 4 horses were descendants of stallion A, the sire and dam of 1 horse were descendants of stallion B, and the sire and dam of 11 horses were descendants of a combination of stallions A and B. The pattern of inheritance resembled an autosomal recessive disorder. Assuming this pattern of inheritance, the conditional probability that these founders were carriers or recessive for the trait was > 99.29% for stallions A and B and 92% for stallion C.
Results support a familial basis for polysaccharide storage myopathy and associated exertional rhabdomyolysis in Quarter Horse-related breeds. The strong contribution of particular founder stallions to the gene pool in some lines of Quarter Horses may explain the high incidence of exertional rhabdomyolysis in these horses.
追踪患马的系谱，确定可能的奠基公马，并计算奠基者基因型的条件概率。
检索加利福尼亚大学戴维斯分校和明尼苏达大学神经肌肉疾病实验室的肌肉活检记录，以识别患有多糖贮积性肌病和运动不耐受/横纹肌溶解症的马匹。尽可能获取包含5至6代的系谱。
13匹美国夸特马、4匹美国花马、3匹阿帕卢萨马和3匹夸特马杂交种（16匹母马、4匹去势雄马和3匹种公马）被确诊患有多糖贮积性肌病。18匹马的系谱信息可用。
计算近亲繁殖系数、奠基者贡献度以及奠基者基因型的条件概率。
3匹种公马（A、B和C）在系谱中显著突出。种公马A和B源自同一父系。平均而言，A在患马的基因中贡献了8.8%（范围为0至23%），B贡献了4.2%（范围为0至14%），C贡献了3.0%（范围为0至14%）。4匹马的父系和母系是种公马A的后代，1匹马的父系和母系是种公马B的后代，11匹马的父系和母系是种公马A和B的组合后代。遗传模式类似于常染色体隐性疾病。假设这种遗传模式，这些奠基者为该性状携带者或隐性基因的条件概率，种公马A和B大于99.29%，种公马C为92%。
结果支持多糖贮积性肌病及相关运动性横纹肌溶解症在夸特马相关品种中具有家族性基础。特定奠基种公马对某些夸特马品系基因库的强烈贡献，可能解释了这些马匹中运动性横纹肌溶解症的高发病率。
