SPRYD4 and Alzheimer disease: SPRYD4 expression levels were identified as increasing risk for AD (OR = 1.08 [1.02–1.16], β [95%CI] = 0.08 [0.02–0.15], p-value = 0.007) and the level of the ratio of histidine to glutamine (β [95%CI] = 0.30 [0.18–0.42], p-value = 1.16 × 10−6).