Hunter N, Goldmann W, Foster J D, Cairns D, Smith G
Institute for Animal Health, Edinburgh.
Vet Rec. 1997 Aug 9;141(6):137-40. doi: 10.1136/vr.141.6.137.
Natural scrapie in sheep is associated with polymorphisms of the PrP gene, particularly at amino acid codons 136, 154 and 171. This paper reports the results of nine scrapie case-control studies in Bleu du Maine, Herdwick, Merino x Shetland, Poll Dorset, Scottish Halfbred, Shetland, Soay, Suffolk and Swaledale sheep from British flocks affected by scrapie. In some outbreaks, scrapie was found to occur only in animals with at least one PrP allele encoding valine at codon 136 (V136), usually a relatively rare allele in healthy controls. In other outbreaks, the V136, PrP allele was either not found or was not an absolute prerequisite for scrapie to develop. Although scrapie had a strong tendency to affect sheep with PrP genotypes homozygous for glutamine at codon 171 (QQ171), these genotypes (QQ171 but varying at other codon positions) were relatively common in healthy controls. The reliable prediction of scrapie susceptibility in previously uninvestigated sheep flocks will therefore require information at least about PrP genotypes at codons 136 and 171.
绵羊的自然痒病与朊蛋白（PrP）基因的多态性有关，尤其是在氨基酸密码子136、154和171处。本文报告了对来自受痒病影响的英国羊群的九种绵羊品种（蓝德美因羊、赫德威克羊、美利奴×设得兰羊、陶赛特羊、苏格兰杂种羊、设得兰羊、索艾羊、萨福克羊和斯韦尔代尔羊）进行的痒病病例对照研究结果。在一些疫情中，发现痒病仅发生在至少有一个在密码子136处编码缬氨酸（V136）的PrP等位基因的动物中，而在健康对照中，该等位基因通常相对罕见。在其他疫情中，未发现V136 PrP等位基因，或者它不是痒病发生的绝对先决条件。尽管痒病强烈倾向于感染在密码子171处为谷氨酰胺纯合子（QQ171）的PrP基因型绵羊，但这些基因型（QQ171，但在其他密码子位置有所不同）在健康对照中相对常见。因此，要可靠地预测此前未调查过的羊群对痒病的易感性，至少需要有关密码子136和171处PrP基因型的信息。
