The urokinase-type plasminogen activator polymorphism PLAU_1 is a risk factor for APOE- epsilon 4 non-carriers in the Italian Alzheimer's disease population and does not affect the plasma A beta (1-42) level

Sporadic Alzheimer's disease (AD) is the most frequent form of dementia in the elderly. A non-conservative polymorphism in the urokinase-type plasminogen activator gene (PLAU_1=RS2227564) has been analyzed, but data are conflicting on whether it is a risk factor for AD. To clarify whether this genetic variant modifies AD risk in the Italian population, we ran a case-control association study on 192 AD and 126 age-matched controls. We did not find any association between PLAU_1 genotype and AD in the whole AD population, but when we stratified our sample by APOE- epsilon 4 status, we found a significant association between PLAU_1 genotype (C/T+T/T) and APOE- epsilon 4 negative AD subjects (p=0.02, xi 2-test). The PLAU_1 genotype did not appear to affect the plasma A beta 42 concentration. Our data support a role for PLAU_1 as an independent genetic risk factor for AD in the Italian population for those subjects who do not have the APOE- epsilon 4 allele.