["Apolipoprotein A1 (apoA1) is the major apolipoprotein constituent of the high-density lipoprotein (HDL) and is involved in reverse cholesterol transport. Variation in the apoA1 gene might influence the function of the protein and, thus, brain cholesterol metabolism, leading to an increased risk for Alzheimer's disease (AD).", 'In the current report, we investigated the role of the functional apoA1 polymorphism (-75 G/A) as a genetic risk factor for AD in a Tunisian population.', '173 AD patients and 150 healthy controls were studied.', 'No association was found between this genetic variation in apoA1 gene and the risk of AD. The presence of the (-75 G/A) A allele appeared, however, to be associated with lower levels of cerebrospinal fluid Aβ42 and HDL cholesterol levels in sera.'] Is polymorphism in apoA1 Influences High-Density Lipoprotein Cholesterol Levels but a Major Risk Factor of Alzheimer 's Disease?