Kowalska A, Wender M, Lannfelt L.
Lack of association between an intronic polymorphism in the presenilin-1 gene and sporadic late-onset Alzheimer disease in Polish patients.Dement Geriatr Cogn Disord.
PubMed Abstract, View on AlzGene
This paper shows the relationship between PS-1 polymorphophism and non-familial sporadic AD patients. We should pay attention to any such studies, including those with negative findings, such as this one.