The association between ACE I/D polymorphism and the risk of Alzheimer’s’ disease in Lebanon

International Conference and Exhibition on Molecular Medicine and Diagnostics

August 24-26, 2015 London, UK

Rajaa Fakhoury, Niveen Masri and Hana Hajeer

Scientific Tracks Abstracts: J Mol Genet Med

Abstract :

Alzheimer’s disease (AD) is a progressive neurodegenerative disease and the most common cause of dementia. AD is characterized
by impairment in memory and other cognitive functions. The two pathological hallmarks of AD are the large extracellular
plaques deposits of the β-amyloid peptides (Aβ) and the intra-neuronal fibrillary tangles of the microtubule binding protein tau.
Aβ peptides are proteolytically derived from a type 1 integral protein termed amyloid precursor protein (APP) and are constantly
anabolized and catabolized in the brain. The accumulation and aggregation of Aβ which is the primary cause of AD, induce an
inflammatory response followed by neuritic injury, hyperphosphorylation of tau protein and formation of fibrillary tangles, leading
ultimately to neuronal dysfunction and cell death. Angiotensin converting enzyme (ACE) is a membrane-bound ectoenzyme that
has been demonstrated to inhibit Aβ peptides aggregation and plaque formation in vitro. ACE gene has been extensively studied as
a candidate gene for Alzheimer’s disease (AD) since ACE was found to be significantly increased in AD patients in several previous
studies. ACE is a dipeptidyl carboxypeptidase widely distributed in the body. ACE gene is located on chromosome 17q23, and has an
insertion and deletion polymorphism (I/D) of a 287 bpAlu repetitive sequence in intron 16.The association of ACE polymorphism
with AD is still controversial. Some meta-analyses addressing the relationship between ACE I/D polymorphism and AD have shown
that the D/D genotype is associated with a reduced risk for AD and that both ID and II genotypes were associated with an increased
AD risk, thus making ACE I allele a risk factor for AD. However, few studies found no evidence to support linkage between ACE I/D
polymorphism and AD. This apparent discrepancy may be due to ethic differences. This study was performed to examine for the first
time the association between ACE I/D polymorphism and the risk of Alzheimer’s disease in Lebanese patients. Forty-five patients
diagnosed as having Alzheimer’s disease and forty-eight age-matched controls from Dar Al-Ajaza Al-Islamia Hospital in Beirut were
recruited, relevant clinical data were confidentially collected such as age, medical history, smoking habits, blood chemistry tests
(such as glucose, lipid profile). A confidentiality letter was signed to safeguard the collected information. Patients and controls were
tested for ACE I/D genotype by PCR. Results showed that the distribution of genotypes between Alzheimer’s patients was: 28.9% DD,
53.3% ID and 17.8% II while the controls showed 35.4% DD, 64.6% ID and 0% II. According to our findings, the II genotype was
significantly higher in Alzheimer’s patients than in controls. Therefore, our study demonstrated the I/I genotype to be associated with
an increased risk of AD in Lebanese population.

Biography :

Rajaa Fakhoury has completed her PhD in Medical Biochemistry from Manchester University. She worked as a dean of the Faculty of Science at Beirut Arab University. Her
research interest is to find association between molecular biomarkers and chronic diseases such as diabetes, hypercholesterolemia and Alzheimer. She has more than 30
publications in this field.