A study in Neurology demonstrated that an increase in cystatin C activity could prevent the development of Alzheimer’s disease, and every 0.1 μmol/L decrease in cystatin C level increased the risk of Alzheimer’s disease by 29% (HR 1.29, 95% CI 1.03−1.63, p < 0.03) (Sundelof et al., 2008). The gene discussed is CST3; the disease is early-onset autosomal dominant Alzheimer disease.