ITPKB and Alzheimer disease: By removing the effect of possible confounding factors that might increase the gene expression variability, the ITPKB mRNA level is significant higher in the PD group without co-morbid AD when compared with healthy controls (ITPKB mRNA= 11.6 ± 2; 4.6 ± 0.86 copies/μL respectively, average ± SEM.