P21 gene variation and late-onset Alzheimer's disease in the Italian population.

Background: Variation at the cyclin-dependent kinase inhibitor gene P21 in a patient sample of the Italian population was investigated in search of genetic factors potentially involved in sporadic late-onset Alzheimer's disease (AD). Methods: Two single nucleotide polymorphisms (SNPs) were studied in this gene: a C>A transversion at codon 31 (ser>arg) in exon 2 (RS1801270) and a C>T transition occurring 20 bp downstream from the stop codon of exon 3 (RS1059234). Results: The odd ratios were: RS1801270 A allele = 0.62 (95% CI = 0.33-1.18; p = 0.14); RS1059234 T allele = 0.57 (95% CI = 0.33-0.98; p = 0.04). In addition, a longer duration of disease was found with genotypes carrying the RS1059234 T allele (4.3 +/- 2.5 years) than with those not carrying it (3.3 +/- 2.1 years) (p = 0.001). Conclusion: In the present sample, one of the two SNPs seems in some way related to AD, since carriers of one allele were slightly protected against AD onset. Copyright (C) 2013 S. Karger AG, Basel