Background: Alzheimer's disease (AD) is a chronic neurodegenerative disorder characterized by impaired memory and progressive cognitive and behavioral decline. Angiotensin converting enzyme (ACE) was suggested to have a role in inhibition of Aβ peptides accumulation with formation of plaque in vitro. The role of ACE (I/D) genotypes regarding AD development and severity is questionable.
Objectives: to assess the role of ACE (I/D) single nucleotide polymorphism (SNP) as a possible genetic risk factor for AD occurrence and for prediction of the disease severity.
Patients and Methods: This case- control study was carried out in the Neuropsychiatry Department, Qena University Hospital during the period between March 1^st 2019 and February 28^th 2020. The study included 50 AD patients and 50 healthy age, sex and education matched controls. All cases underwent clinical assessment using Mini Mental State Examination (MMSE), Advanced medical imaging with computed tomography (CT) or magnetic resonance imaging (MRI) of the brain. Genetic analysis for ACE (I/D) (rs4646994) was done using conventional PCR with primers without restriction enzyme.
Results: Mean age of the included patients was 70.1 ± 9.35 years with female predominance (60%). About 46% of patients had mild disease, 42% had moderate disease and 12% had severe disease based on MMSE assessment tool. Diabetes had higher frequency among AD group (30%). ACE homozygous DD genotype had higher frequency (OD=35.9; 95%CI= [2.8-440.2]) and D allele was significantly commoner among AD group than control group (OD=2.13; 95% CI= [1.05-3.2]), (P ˂ 0.05 for all). However, no statistically significant differences in relation to degree of dementia and ACE (I/D) genotypes were recorded. Although homozygous DD genotype and D alleles had higher frequency among severe AD group (P˃0.05).
Conclusion: an evidence of significant association between homozygous ACE (DD) and D allele among sample of AD patients in Upper Egypt. However, there is lack of significance association of ACE (I/D) SNP in prediction of disease severity.