Introduction: Alzheimer's disease (AD) is a progressive, neurodegenerative disease. Many studies proposed an association of the insertion (I)/deletion (D) polymorphism (indel) in intron 16 of the gene for angiotensin I-converting enzyme (ACE) on chromosome 17q23 with Alzheimer's disease. ACE indel and related haplotypes associated with AD risk have reduced plasma ACE whereas protective genotypes have elevated ACE.Object: To investigate whether there is a correlation between polymorphisms of the ACE I/D locus gene and AD in Egyptian patients and to determine whether there is a difference in ACE activity in the plasma of clinically diagnosed AD patients.Methods: Subjects of this study are 84 dementia patients diagnosed as having Alzheimer's disease, 45 males and 39 females aged 65 ± 7 years from the Geriatric Department at Ain-Shams University Hospitals and 86 individuals as non dementia controls, 44 males and 42 females aged 63 ± 6 years.All subjects were genotyped for the common insertion/deletion polymorphisms for ACE gene locus, and ACE plasma activity assay was measured for AD patients.Results: There was statistically significant difference in the frequency of the ACE insertion/deletion alleles between the cases and controls where the I allele distribution in AD cases and controls was 74% vs. 15%, and the I/I genotype frequency was 60% vs. 5%, respectively. They both reached a statistical significance range (I allele frequency: OR = 3.714, 95% CI 1.311-10.523, p < 0.01; I/I

■ AbstractOxidative stress, characterized by a marked increase in the level of oxygen free radicals (OFR), has been implicated in the development of diabetic microangiopathic complications, such as diabetic neuropathy (DN) and nephropathy (DP). Antioxidant enzymes may protect against the rapid onset and progression of microangiopathy, by reducing the excess of OFR and peroxides. Mutations and polymorphisms in genes encoding such enzymes may therefore result in a predisposition to this disorder. AIM: we investigated the role of genes encoding the antioxidant enzyme, mitochondrial superoxide dismutase (Mn-SOD2), in DN and DP pathogenesis in an Egyptian population. We studied Ala(-9)Val polymorphism of the Mn-SOD2 gene in type 1 diabetic patients (n = 65) with DN (n = 40) or DP (n = 45). METHODS: we used polymerase chain reaction (PCR) assays with restriction fragment length polymorphism for rapid detection of polymorphisms. These assays involved the use of mismatch PCR primers to create restriction sites in the amplified product only in presence of the polymorphic base. The PCR product was then digested with AgeI restriction enzyme to detect Ala(-9)Val polymorphic sites. RESULTS: the frequencies of the Ala allele (odds ratio (OR) = 0.438, 95% CI of 0.247 -0.778) and the Ala/Ala genotype (OR = 0.26, 95% CI of 1.39 -10.266) were significantly lower in diabetic neuropathy patients. In contrast, the frequencies of the Val allele (OR = 2.282, 95% CI of 1.286 -4.05) and the homozygous Val/Val genotype (OR = 6.68, 95% CI of 0.3 -0.76) were significantly higher in patients with DN than diabetics without neuropathy. Although the Val allele was more frequently detected in DP patients than diabetics without nephropathy (OR = 3.2), this difference was statistically non-significant. In conclusion, Ala(-9)Val substitution in the Mn-SOD2 gene was associated with DN in Egyptian diabetic children but not a significant factor in diabetic patients with nephropathy.