The APOE Genotype in Idiopathic Normal Pressure Hydrocephalus

INTRODUCTION: Amyloid plaque has been reported in brain biopsies from patients with idiopathic normal-pressure hydrocephalus (iNPH) and proposed as a significant feature of the pathophysiology. Presence of the apolipoprotein E ε4 (APOE ε4) allele is associated with increased risk of Alzheimer’s disease (AD). AIMS: To compare the distribution of APOE genotype in iNPH patients with an age-matched population-based control group and with Alzheimer’s disease (AD) patients. METHODS: APOE genotype frequencies were determined in 77 iNPH patients (50 men and 27 women, mean age 71.7 years) diagnosed with iNPH, a sample of 691 AD patients and 638 age-matched population controls (299 men and 339 women) from the INTERGENE cohort. RESULTS: The APOE distribution did not differ significantly between the iNPH patients and the control population. The per e4-allele odds-ratio (OR) of iNPH was given by OR = 0.90, 95% confidence interval (CI) = (0.50, 1.60) that was considerably smaller than the per-allele OR of AD, OR = 5.34 (4.10, 7.00). CONCLUSION: The results suggest that the APOE-related risk of AD in patients with iNPH is not higher than in the general population.