Abstract
SCRAPIE, a subacute neuromuscular disease of middle-aged sheep, has been attributed variously to an infection or to heredity1,2. The clinical disorder follows progressive symmetrical decay of neurones in localised brain sites, notably the hypothalamo–neurophysial and olivo-pontocerebellar ‘systems’ (ref. 3), associated with a terminal axon dystrophy4–9. An artificially transmissible spongiform encephalopathic agent (TSEPA), or ‘slow virus’, to which many attribute the disease10,11, is commonly present in diseased animals but its aetiological role remains unclear. Based on the clinical manifestation of natural scrapie, I have proposed that the disease is controlled by an autosomal recessive gene1,2,12. This hypothesis allowed identification of the three presumptive genotypes (ss, sS, SS), and precise prediction of attack rates13,14, amenable to quantitative experimental verification15. The evidence summarised here, which has been compiled since 1958, provides strong support for my hypothesis.
Published Version
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