Response to: Lescai F. et al. (2011) J Alzheimers Dis 24, 235-245

1 May 2011

We have read with interest the paper of Lescai et al. We were quite surprised by the lack of any reference to a previous study of Bizzarro et al., already reporting these results. In a relative large sample of AD cases from Central and Southern Italy Bizzarro et al. observed a significant association of the -219 (rs405509) polymorphism with AD. Similar, an association of the -219/e4 haplotypes with AD was also reported. Therefore, the study of Lescai et al. in a wide sample of AD patients confirmed the role of the -219 polymorphism as risk factor for AD in Italy and that promoter genotypes and APOE haplotypes might have a complex function as AD-associated genetic risk factors. We feel that the consideration and the evaluation of these results put in the complexity of the discussion of this controversial issue would have been beneficial for the completeness of the published paper and of a major interest for a more analytical information to the readers on the state-of-art on this topic.

Carlo Masullo, MD
Davide Seripa, PhD
Alessandra Bizzarro MD, PhD

Bizzarro A, Seripa D, Acciarri A, Matera MG, Pilotto A, Tiziano FD, Brahe C, Masullo C (2009) The complex interaction between APOE promoter and AD: an Italian case-control study. Eur J Hum Genet 17, 938-945.


Response to Letter to the Editor from Masullo et al.

We thank Dr. Bizzarro et al. their observation, which adds important information to our paper. Their study was not included in the first draft references of our manuscript mainly due to the number of samples used (169 cases and 99 controls). The power of the association and GLM tests on EM estimated haplotypes, calculated according to Shaid et al. showed that we were able to achieve a power of 0.99 only with an almost ten-fold a sample size. We agree however with the authors that their study strengthens the overall picture of haplotypes and interactions affecting APOE correlation with Alzheimer's and age-related diseases.

Best regards,
Francesco Lescai, PhD, EDBT