但光靠基因测试无法作为准确的指标，因为大约一半的阿尔茨海默症患者不携带ε4，并且可能有一半的ε4携带者不会发生阿尔茨海默症。
But genetic testing alone is unlikely to be an accurate predictor, because around half of Alzheimer’s sufferers do not carry ε4, and probably half of those with ε4 do not develop the disease.