UBQ-8i polymorphism is not an independent risk factor for mild cognitive impairment and Alzheimer's disease in APOE-4 carriers.

Background: Alzheimer's disease (AD) has a complex genetic etiology, and as a result many genes have been studied to determine how they might be involved with the disease. Amyloidogenic effects have been broadly linked with familial forms of the disease, though certain genes such as UBQLN1 could also play a role in prodromal phases such as amnesic mild cognitive impairment (MCI).

Aim: The aim of this study is to examine the role of the UBQ-8i (rs12344615) functional polymorphism in the UBQLN1 gene as a risk factor for MCI and AD and its possible synergies with apolipoprotein gene E (APOE).

The COMT Val158 Met polymorphism as an associated risk factor for Alzheimer disease and mild cognitive impairment in APOE 4 carriers.

Background: The aim of this study is to examine the influence of the catechol-O-methyltranferase (COMT) gene (polymorphism Val158 Met) as a risk factor for Alzheimer's disease (AD) and mild cognitive impairment of amnesic type (MCI), and its synergistic effect with the apolipoprotein E gene (APOE).A total of 223 MCI patients, 345 AD and 253 healthy controls were analyzed. Clinical criteria and neuropsychological tests were used to establish diagnostic groups.