The variant rs601338 in FUT2 has been associated with resistance to Norwalk virus infection,25 rs10774671 in OAS1 with diabetes type 1 susceptibility,26 rs3892097 in CYP2D6 with poor metabolism of debrisoquine,27 and rs3832852 in A2M with the pathogenesis of Alzheimer's disease.28 Here, OAS1 is linked to early-onset autosomal dominant Alzheimer disease.