Angiotensin I-converting enzyme (ACE): estimation of DNA haplotypes in unrelated individuals using denaturing gradient gel blots

Abstract

The angiotensin I-converting enzyme (ACE) gene (17q23) is a candidate gene for essential hypertension and related diseases, but investigation of its role in human pathology is hampered by a lack of identified polymorphisms. Currently, a 287-bp insertion/deletion (I/D) RFLP in intron 16 represents the only one known. Additional polymorphisms for the ACE gene would make most families informative for linkage studies and would allow haplotypes to be assigned in association studies. To increase the information provided by the ACE gene, we used a sensitive screening technique, denaturing gradient gel electrophoresis (DGGE) blots, to identify polymorphisms and combined this with gene counting to identify haplotypes. Five independent polymorphisms, restriction fragment melting polymorphisms (RFMPs), were identified by four probes (encompassing half of the ACE cDNA) in digests produced by three restriction enzymes (DdeI, RsaI, and AluI). One RFMP has three alleles while the others have two alleles. In a sample of 67 unrelated control subjects, minor allele frequencies ranged from 0.12 to 0.49. A significant level of linkage disequilibrium was found for all pairs of markers. The four most informative RFMPs, taken in combination, define 24 potential haplotypes. Based on gene counting, 11 of the 24 are rare or nonexistent in this population, and the estimated heterozygosity of the remaining 13 haplotypes approaches 80%. Under these conditions for the ACE locus, phase-unknown genotypes could be assigned to haplotype pairs in unrelated subjects with reasonable certainty. Thus, using DGGE blot technique for identifying numerous DNA polymorphisms in a candidate locus, in combination with gene counting, one can often identify DNA haplotypes for both related and unrelated study subjects at a candidate locus. These markers in the ACE gene should be useful for clinical and epidemiologic studies of the role of ACE in human disease.

Gene polymorphisms of angiotensin-converting enzyme and angiotensin II Type 1 receptor among chronic kidney disease patients in a Chinese population

“…23 The AGTR1-A1166C polymorphism had been investigated in many studies in relation to blood pressure, and sometimes in relation to renal failure risk and other risk factors, producing a variety of results. [27][28][29][30][31] However, our study showed no difference between the CKD and control groups on the A1166C polymorphism. The AGTR1-C521T C polymorphism also did not differ greatly in frequency between the CKD and control groups.…”

A Haplotype at the Adiponectin Locus Is Associated With Obesity and Other Features of the Insulin Resistance Syndrome

“…Data analysis. Haplotypes at the 45 and 276 loci were inferred for each individual by maximum likelihood methods as previously described (25). Study subjects with phase-unknown genotype (i.e., heterozygotes at both SNPs) were assigned to the most likely haplotype phase (TT/GG).…”

Synergistic effect of angiotensin II type 1 receptor genotype and poor glycaemic control on risk of nephropathy in IDDM

“…The distribution of genotypes and alleles were compared between study groups by chi-square tests [29]. Haplotype frequencies were estimated by gene counting as previously described [30]. As a descriptive measure of association between genotypes and outcomes, odds ratios were calculated along with 95 % confidence intervals [29].…”