The D Allele of Angiotensin-Converting Enzyme Polymorphism as a Predictor of Renal Function Decline over 4 Years in an Apparently Healthy Chinese Population Aged 60 and Older

Use of Genetic Algorithm Combinational Single-nucleotide Polymorphisms Could Modify the Association of Blood Lead Levels and Bone Matrix Density

BACKGROUND

Previous studies have not explored the relationship between a single gene and a single disease. Our study aims to investigate the association of multiple genotypes with blood lead levels and bone matrix density (BMD) by using genetic algorithms.

METHODS

Our research focused on 506 employees (245 males and 261 females) of a lead battery factory in Taiwan. We collected data on their BMD, blood lead level, and 6 SNPs (ACE, alpha-adducin, Bsm, Tag, Apa, and ALAD); these factors were analyzed using discrete binary particle swarm optimization (DBPSO) and logistic regression analysis.

RESULTS

We found no association between blood lead level and bone density, which may be due to the relatively young age of this population (mean age = 45.1 years). However, the genotype that contained both Bsm type bb and ALAD type 1-1 may play an important role in protecting against lower bone density among these employees.

CONCLUSIONS

In conclusion, this study found that the Bsm and ALAD genes influence bone density among lead workers. However, the mechanism and exact relationship between these two genes and bone density require further investigation.

Meta-analysis of the relationship between ACE I/D gene polymorphism and end-stage renal disease in patients with diabetic nephropathy

AIMS

  Diabetic nephropathy (DN) is the major cause for end-stage renal disease (ESRD) and the pathogenesis for DN developing into ESRD is not clear at present. Results from published studies on the relationship between angiotensin-converting enzyme (ACE) insertion/deletion (I/D) gene polymorphism and ESRD risk in DN patients are still conflicting. This meta-analysis was performed to evaluate the association between ACE I/D gene polymorphism and ESRD risk in DN patients.

METHODS

  Association studies were identified from the databases of PubMed, Embase and Cochrane Library on 1 October 2011, and eligible investigations were identified and synthesized using the meta-analysis method. Results were expressed using odds ratios (OR) for dichotomous data and 95% confidence intervals (CI) were also calculated.

RESULTS

  Twelve studies reporting the relation between ACE I/D gene polymorphism and ESRD risk in DN patients were identified. In overall populations, there was a notable association between D allele or DD genotype and ESRD susceptibility (D: OR = 1.32, 95% CI: 1.11-1.56, P = 0.002; DD: OR = 1.67, 95% CI: 1.25-2.21, P = 0.0004). In the sub-group analysis according to ethnicity, D allele or DD genotype was associated with ESRD risk in Asians. In Caucasians, the association of DD genotype with ESRD risk was observed, but the D allele was not. Furthermore, ACE I/D gene polymorphism was associated with ESRD risk in patients with DN due to diabetes mellitus type 2, but the association was not found for patients with DN due to diabetes mellitus type-1.

CONCLUSIONS

  Our results indicate that D allele or DD homozygous is associated with the ESRD susceptibility in DN patients. However, more investigations are required to further this association.

The Gly460Trp polymorphism of alpha-adducin gene as a predictor of renal function decline over 4 years of follow-up in an apparently healthy Chinese population

There were conflict data between alpha-adducin Gly460Trp genetic variant and changes of renal function. We conducted a prospective study to investigate the influence of alph-adducin Gly460Trp polymorphism on the quantitative changes of renal function. Of 1500 people screened, 112 non-diabetic normotensive elderly Chinese were recruited and received biochemistry examination at the baseline, at the second and fourth year follow-up. Serum creatinine and calculated renal parameter, using Modification of Diet in Renal Disease (MDRD) Study, were used to evaluate renal function and their progression. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism. Age was 71.9 ± 3.7 years (range 60-81). Serum creatinine and MDRD glomerular filtration rate (GFR) were significantly worsened at the 2 and 4-year follow-up (all P < 0.001). The magnitude of 4-year decline of MDRD GFR was significantly higher in subjects carrying the a-adducin Gly460Trp G-allele than TT genotype (P = 0.045). The multivariate analyses showed that a-adducin Gly460Trp (P = 0.034), baseline MDRD GFR (P < 0.001), diastolic blood pressure (P = 0.021) and body weight (P = 0.022) could independently predict 4-year change of MDRD GFR. This longitudinal study showed that the aging process was associated with decline of renal function in the healthy elderly. The alpha-adducin Gly460Trp gene polymorphism might modulate these changes in the Chinese. This provides further knowledge essential in the assessment of renal disease and determination of renal function in the older subjects.

An alternative method for genotyping of the ACE I/D polymorphism

The mistyping of the angiotensin I-converting enzyme insertion/deletion (ACE I/D) has been well documented, and new methods have been suggested here to improve the genotyping efficiency. Buccal cell samples were collected from 157 young Caucasians, and genotyped using previously known and newly developed PCR amplification genotyping techniques, as well as PCR-RFLP tests for three single nucleotide polymorphisms (rs4327, rs4341 and rs4343). Inconsistent genotyping results were found when using only the PCR amplification genotyping techniques across repeated attempts (8% to 45%), however, individual SNP genotyping was highly consistent (100%). Two SNPs (rs4341 and rs4343) were in complete LD and SNP rs4327 was in high LD with the ACE I/D. The ACE I/D was in HW equilibrium in the portion of the population with consistent genotyping results, whereas the three SNPs were not in HW equilibrium. The mistyping of ACE I/D by only PCR amplification can be improved using alternative methods.