Computational Screening and Exploration of Disease-Associated Genes in Alzheimer's Disease

Alzheimer's Disease: The Role of Mutations in Protein Folding

Misfolded proteins result when a protein follows the wrong folding pathway. Accumulation of misfolded proteins can cause disorders, known as amyloid diseases. Unfortunately, some of them are very common. The most prevalent one is Alzheimer's disease. Alzheimer's disease is a neurodegenerative disorder and the commonest form of dementia. The current study aims to assess the impact of somatic mutations in PSEN1 gene. The said mutations are the most common cause of familial Alzheimer's disease. As protein functionality can be affected by mutations, the study of possible alterations in the tertiary structure of proteins may reveal new insights related to the relationship between mutations and protein functions. To examine the effect of mutations, the primary structures and their related mutations were retrieved from public databases. Each structure (mutated and unmutated) was predicted based on effective structure prediction methodologies. A benchmarking of the structural predictive tools was accomplished. Comparative analyses of mutated and unmutated proteins were performed based on classic bioinformatics methods (TM-Score, RMSD, etc.) as well as on established shape-based descriptors retrieved from object recognition methodologies. Unsupervised methodologies were applied to the structures, in order to identify groups of mutation with similar mutational impact. Our results provide an essential knowledge toward protein's functionality in structure-based drug design.

The Impact of EGFR Gene Polymorphisms on the Risk of Alzheimer's Disease in a Chinese Han Population: A Case-Controlled Study

BACKGROUND The aim of this study was to investigate the association between polymorphisms of the epidermal growth factor receptor (EGFR) gene with the risk of Alzheimer's disease (AD) in a Chinese Han population. MATERIAL AND METHODS A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was used to genotype 139 patients with AD and 152 healthy control individuals. The Hardy-Weinberg equilibrium (HWE) was analyzed using the chi-squared (χ²) test, and genotype and allele frequencies were compared between the two population groups, using the χ² test. The odds ratios (ORs) and corresponding 95% confidence intervals (CI) were calculated to express the degree of risk of AD resulting from polymorphisms in the EGFR gene. Linkage disequilibrium among EGFR polymorphisms was analyzed using the Haploview bioinformatics software. RESULTS The CC genotype and C allele frequencies of rs730437 were significantly lower in patients with AD compared with the controls (P=0.037), indicating that rs730437 was associated with a reduced risk of AD (CC vs. AA: OR=0.446, 95% CI=0.207-0.960) (C vs. A: OR=0.702, 95% CI=0.502-0.980). The presence of the TT genotype of rs1468727 significantly reduced the risk of AD (P=0.003; OR=0.333, 95% CI=0.160-0.691), and T allele carriers of rs1468727 had a 0.605-fold increased risk of AD. Haplotype A-C-C was significantly correlated with an increased risk of AD (OR=1.922, 95% CI=1.130-3.269). CONCLUSIONS In a Han Chinese population, EGFR gene polymorphisms, rs730437 and rs1468727 and haplotype A-C-C were shown to be possible protective factors for the development of AD.