Alpha-adducin Gly460Trp polymorphism and hypertension risk: a meta-analysis of 22 studies including 14303 cases and 15961 controls

The adducin saga: pleiotropic genomic targets for precision medicine in human hypertension-vascular, renal, and cognitive diseases

Hypertension is a leading risk factor for stroke, heart disease, chronic kidney disease, vascular cognitive impairment, and Alzheimer's disease. Previous genetic studies have nominated hundreds of genes linked to hypertension, and renal and cognitive diseases. Some have been advanced as candidate genes by showing that they can alter blood pressure or renal and cerebral vascular function in knockout animals; however, final validation of the causal variants and underlying mechanisms has remained elusive. This review chronicles 40 years of work, from the initial identification of adducin (ADD) as an ACTIN-binding protein suggested to increase blood pressure in Milan hypertensive rats, to the discovery of a mutation in ADD1 as a candidate gene for hypertension in rats that were subsequently linked to hypertension in man. More recently, a recessive K572Q mutation in ADD3 was identified in Fawn-Hooded Hypertensive (FHH) and Milan Normotensive (MNS) rats that develop renal disease, which is absent in resistant strains. ADD3 dimerizes with ADD1 to form functional ADD protein. The mutation in ADD3 disrupts a critical ACTIN-binding site necessary for its interactions with actin and spectrin to regulate the cytoskeleton. Studies using Add3 KO and transgenic strains, as well as a genetic complementation study in FHH and MNS rats, confirmed that the K572Q mutation in ADD3 plays a causal role in altering the myogenic response and autoregulation of renal and cerebral blood flow, resulting in increased susceptibility to hypertension-induced renal disease and cerebral vascular and cognitive dysfunction.

The Association between Gly460Trp-Polymorphism of Alpha-Adducin 1 Gene (ADD1) and Arterial Hypertension Development in Ukrainian Population

Arterial hypertension (AH) belongs to the diseases with genetic predisposition that determines the necessity of research on the genetic component's influence on this disease development. It is suggested that one of the salt-sensitive arterial hypertension potential markers may be the alpha-adducin gene because its protein product is involved in the ion transport regulation in the renal epithelium. Thus, the aim of the study was to investigate the association between ADD1 Gly460Trp-polymorphism and the AH development risk among patients with different risk factors in the Ukrainian population. The study included 232 Ukrainians: 120 patients with diagnosed arterial hypertension and 112 practically healthy individuals. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was used for ADD1 Gly460Trp-polymorphism genotyping. The ADD1 Gly460Trp-polymorphic locus is an important predictor of arterial hypertension development in the Ukrainian population, but other nongenetic factors should be considered in further studies.

Prevalence of hypertension among adolescents (10-19 years) in India: A systematic review and meta-analysis of cross-sectional studies

BACKGROUND

Despite the well-known short-term and long-term ill effects of elevated blood pressure in children and adolescents, pooled data on its burden among Indian adolescents have not yet been synthesized.

OBJECTIVES

We did a systematic review with meta-analysis to calculate the pooled prevalence of hypertension among adolescents (10-19 years) in India.

METHODS

We searched PubMed, Embase, Cochrane library, Google Scholar and IndMed, and included cross-sectional studies reporting data on hypertension prevalence among 10 to19 years old and published in English language from their inception till 1st March 2020. Modified New castle Ottawa scale was used to assess risk of bias based on research design, recruitment strategy, response rate and reliability of outcome determination. A random effects model was used to estimate pooled prevalence, and heterogeneity was assessed using Cochrane's Q statistic test of heterogeneity and I2 statistic. To explore the heterogeneity, we did a meta-regression, and sub-group analyses based on region, study setting and number of blood pressure readings.

RESULTS

Out of 25 studies (pooled sample of 27,682 participants) six studies were of high, eighteen of moderate, and one was of low quality. The prevalence of hypertension across studies ranged from 2% to 20.5%, with a pooled estimate of 7.6% (95% CI: 6.1 to 9.1%), I2 = 96.6% (p-value <0.001). Sub-group analysis restricted only to the western India demonstrated a smaller heterogeneity (I2 = 18.3%). In univariate model of meta-regression, diagnostic criteria was significantly associated with pooled prevalence (-4.33, 95%CI: -7.532, -1.134).

CONCLUSION

The pooled prevalence of hypertension among adolescent in India is 7.6% with substantial heterogeneity between the studies. To tackle the high prevalence of hypertension among adolescents, early detection by screening under school health programme and opportunistic screening at Paediatric OPD should be implemented by Policy makers.

The genetic risk for hypertension is lower among the Hungarian Roma population compared to the general population

Estimating the prevalence of cardiovascular diseases (CVDs) and risk factors among the Roma population, the largest minority in Europe, and investigating the role of genetic or environmental/behavioral risk factors in CVD development are important issues in countries where they are significant minority. This study was designed to estimate the genetic susceptibility of the Hungarian Roma (HR) population to essential hypertension (EH) and compare it to that of the general (HG) population. Twenty EH associated SNPs (in AGT, FMO3, MTHFR-NPPB, NPPA, NPPA-AS1, AGTR1, ADD1, NPR3-C5orf23, NOS3, CACNB2, PLCE1, ATP2B1, GNB3, CYP1A1-ULK3, UMOD and GNAS-EDN3) were genotyped using DNA samples obtained from HR (N = 1176) and HG population (N = 1178) subjects assembled by cross-sectional studies. Allele frequencies and genetic risk scores (unweighted and weighted genetic risk scores (GRS and wGRS, respectively) were calculated for the study groups and compared to examine the joint effects of the SNPs. The susceptibility alleles were more frequent in the HG population, and both GRS and wGRS were found to be higher in the HG population than in the HR population (GRS: 18.98 ± 3.05 vs. 18.25 ± 2.97, p<0.001; wGRS: 1.52 [IQR: 0.99–2.00] vs. 1.4 [IQR: 0.93–1.89], p<0.01). Twenty-seven percent of subjects in the HR population were in the bottom fifth (GRS ≤ 16) of the risk allele count compared with 21% of those in the HG population. Thirteen percent of people in the HR group were in the top fifth (GRS ≥ 22) of the GRS compared with 21% of those in the HG population (p<0.001), i.e., the distribution of GRS was found to be left-shifted in the HR population compared to the HG population. The Roma population seems to be genetically less susceptible to EH than the general one. These results support preventive efforts to lower the risk of developing hypertension by encouraging a healthy lifestyle.

A Review of the Epidemiological Evidence for Adducin Family Gene Polymorphisms and Hypertension

Hypertension is one of the most common cardiovascular diseases that seriously endangers human health and has become a significant public health problem worldwide. In the vast majority of patients, the cause of hypertension is unknown, called essential hypertension (EH), accounting for more than 95% of total hypertension. Epidemiological and genetic studies of humans and animals provide strong evidence of a causal relationship between high salt intake and hypertension. Adducin is one of the important candidate genes for essential hypertension. Adducin is a heterodimeric or heterotetrameric protein that consists of α, β, and γ subunits; the three subunits are encoded by genes (ADD1, ADD2, and ADD3) that map to three different chromosomes. Animal model experiments and clinical studies suggest that changes in single-nucleotide polymorphisms (SNPs) at part of the adducin family gene increase the Na⁺-K⁺-ATPase activity of the renal tubular basement membrane and increase the reabsorption of Na⁺ by renal tubular epithelial cells, which may cause hypertension. This review makes a summary on the structure, function, and mechanism of adducin and the role of adducin on the onset of EH, providing a basis for the early screening, prevention, and treatment of EH.

Genomics and Pharmacogenomics of Salt-sensitive Hypertension

Salt sensitivity is estimated to be present in 51% of the hypertensive and 26% of the normotensive populations. The individual blood pressure response to salt is heterogeneous and possibly related to inherited susceptibility. Although the mechanisms underlying salt sensitivity are complex and not well understood, genetics can help to determine the blood response to salt intake. So far only a few genes have been found to be associated with salt-sensitive hypertension using candidate gene association studies. The kidney is critical to overall fluid and electrolyte balance and long-term regulation of blood pressure. Thus, the pathogenesis of salt sensitivity must involve a derangement in renal NaCl handling: an inability to decrease renal sodium transport and increase sodium excretion in the face of an increase in NaCl load that could be caused by aberrant counter-regulatory natriuretic/antinatriuretic pathways. We review here the literature regarding the gene variants associated with salt-sensitive hypertension and how the presence of these gene variants influences the response to antihypertensive therapy.

Genomics and pharmacogenomics of salt-sensitive hypertension Minireview

Salt sensitivity is estimated to be present in 51% of the hypertensive and 26% of the normotensive populations. The individual blood pressure response to salt is heterogeneous and possibly related to inherited susceptibility. Although the mechanisms underlying salt sensitivity are complex and not well understood, genetics can help to determine the blood response to salt intake. So far only a few genes have been found to be associated with salt-sensitive hypertension using candidate gene association studies. The kidney is critical to overall fluid and electrolyte balance and long-term regulation of blood pressure. Thus, the pathogenesis of salt sensitivity must involve a derangement in renal NaCl handling: an inability to decrease renal sodium transport and increase sodium excretion in the face of an increase in NaCl load that could be caused by aberrant counter-regulatory natriuretic/antinatriuretic pathways. We review here the literature regarding the gene variants associated with salt-sensitive hypertension and how the presence of these gene variants influences the response to antihypertensive therapy.

Gene polymorphisms of adducin GLY460TRP, ACE I/D, AND AGT M235T in pediatric hypertension patients

BACKGROUND

Hypertension is a major global public health problem that affects both pediatric and adult populations. ACE I/D, AGT M235T, and ADD Gly460Trp polymorphisms are thought to be associated with primary hypertension. In the present study, we examined the frequency of these polymorphisms in a pediatric population with secondary hypertension.

MATERIAL AND METHODS

Included in the study were 58 hypertensive and 58 normotensive pediatric patients. ACE I/D and AGT M235T polymorphisms are determined by conventional PCR; ADD Gly460Trp polymorphism was investigated using PCR amplification of genomic DNA.

RESULTS

There were significant differences between the control group and pediatric hypertensive group in terms of ACE I/D (P<0.05) and AGT M235T (P<0.05) polymorphisms, but there were no differences in ADD Gly460Trp (P>0.05) polymorphism.

CONCLUSIONS

We suggest that RAS gene polymorphisms (ACE-I/D, AGT M235T) are significantly associated with susceptibility to diseases that lead to secondary hypertension.

Role of leptin receptor gene polymorphisms in susceptibility to the development of essential hypertension: a case-control association study in a Northern Han Chinese population

In order to explore the potential association between the leptin receptor (LEPR) gene polymorphisms and essential hypertension (EH) risk in the Northern Han Chinese population, we recruited 823 hypertensive subjects and 491 healthy control subjects from the Northern Han Chinese. Genotyping was performed to identify the Lys109Arg, Gln223Arg and Lys656Asn polymorphisms of the LEPR gene. Significant associations were found in a dominant genetic model ([GG+AG] vs AA), P=0.007, odds ratio (OR)=3.697, 95% confidence interval (CI) 1.442–9.482), and in homozygote comparison (GG vs AA, P=0.005, OR=3.890, 95% CI 1.501–10.077) for the Gln223Arg polymorphism. No significant association could be found between Lys109Arg or Lys656Asn polymorphism and EH risk. Linkage disequilibrium was detected between the Lys109Arg and Gln223Arg polymorphisms, and haplotype analyses identified that the G-A haplotype was a protective haplotype for EH. Our studies demonstrated that the LEPR Gln223Arg polymorphism had an important role in a patient's susceptibility to EH in the Northern Han Chinese population.

α-Adducin gene G614T polymorphisms in essential hypertension patients with high low density lipoprotein (LDL) levels

BACKGROUND & OBJECTIVES

The association between α-adducin gene G614T polymorphism and essential hypertension (EH) is not clear. The present study was carried out to examine a possible association between α-adducin gene G614T mutation and essential hypertension in Chinese population.

METHODS

A total of 170 patients with essential hypertension (EH group) and 154 normotensive subjects (Control group) were genotyped for the cytoskeletal protein single nucleotide polymorphism G614T of the α-adducin gene by PCR-RFLP technique. Systolic blood pressure (SBP), diastolic blood pressure (DBP), body mass index (BMI), low density lipoprotein (LDL), high-density lipoprotein (HDL), high-sensitivity C-reactive protein (hs-CRP), left atrial diameter (LA DIA), left ventricular diameter (LV DIA) and other parameters were recorded in EH group.

RESULTS

There was significant association between EH and α-adducin genotypes (P<0.05). GT and TT genotypes in EH group had higher LDL levels as compared to GG carriers (P<0.05). The LDL concentration was significantly elevated in patients with GT and TT genotypes. The LDL levels also differed significantly in male patients with all the three genotypes.

INTERPRETATION & CONCLUSIONS

A significant association was found between ADD1 gene G614T polymorphism and EH in Chinese patients. Further studies need to be done to confirm these findings in a large sample.

Lower ADD1 gene promoter DNA methylation increases the risk of essential hypertension

The goal of our study is to investigate the contribution of promoter DNA methylation of α-adducin (ADD1) gene to the risk of essential hypertension (EH). Using the bisulphite pyrosequencing technology, DNA methylation levels of five CpG dinucleotides on ADD1 promoter were measured among 33 EH cases and 28 healthy controls. Significantly higher ADD1 DNA methylation levels were observed in the females than in the males (CpG1: P = 0.016; CpG2-5: P = 0.021). A breakdown analysis by gender showed that lower CpG1 methylation was associated with an increased risk of EH in females (adjusted P = 0.042). A much more significant association between lower CpG2-5 methylation levels and the increased risk of EH was found in males (adjusted P = 0.008). CpG1 methylation was inversely correlated with age in females (r = -0.407, P = 0.019) but not in males. ADD1 CpG1 and CpG2-5 methylation levels were significantly lower in post-menopausal (>50 years) women than pre-menopausal (≤50 years) women (CpG1: P = 0.006; CpG2-5: P = 0.034). A significant interaction between CpG1 methylation and age was found in females (CpG1*age: P = 0.029). CpG2-5 methylation was shown as a significant predictor of EH in males [area under curve (AUC) = 0.855, P = 0.001], in contrast that CpG1 methylation was a trend toward indicator in females (AUC = 0.699, P = 0.054). In addition, significant differences were observed between males and females for alanine aminotransferase (ALT, P = 0.001), aspartate aminotransferase (AST, P = 0.005) and uric acid (P<0.001). The concentration of AST was inversely correlated with ADD1 CpG2-5 methylation levels in female controls (r = -0.644, P = 0.024). These observations may bring new hints to elaborate the pathogenesis of EH.

Association between polymorphisms of alpha-adducin gene and essential hypertension in Chinese population

The association between polymorphisms of α-adducin (ADD1) gene and essential hypertension is still unclear. Thus, we carried out a case-control study and an interaction analysis to test whether ADD1 is a common candidate gene for hypertension in the Chinese population. Blood samples and information including body mass index (BMI), smoking habit, and alcohol abuse were collected. Meanwhile, total cholesterol, high density lipoprotein, triglyceride were measured by automatic biochemistry analyzer. All 6 tag single nucleotide polymorphisms (tagSNPs) within ADD1 gene were genotyped by SNPstream genotyping system. Multifactor dimensionality reduction (MDR) was used to identify the interactions among the SNPs and the non-genetic factors. Results showed that plasma triglyceride, total cholesterol, and BMI were significantly higher in the hypertensive group than in the control group. Result from genotyping indicated that rs4963 was significantly associated with essential hypertension. After stratification by gender, rs4963 was associated with essential hypertension only in males. MDR analysis indicated that interaction among BMI, rs4963, and rs16843452 were involved in susceptibility of hypertension. The present study indicated that rs4963 within ADD1 gene was associated with essential hypertension in Chinese population, which might be related to altered exonic splicing and disrupted gene regulation.

Association between polymorphisms of alpha-adducin gene and essential hypertension in Chinese population

The association between polymorphisms of α-adducin (ADD1) gene and essential hypertension is still unclear. Thus, we carried out a case-control study and an interaction analysis to test whether ADD1 is a common candidate gene for hypertension in the Chinese population. Blood samples and information including body mass index (BMI), smoking habit, and alcohol abuse were collected. Meanwhile, total cholesterol, high density lipoprotein, triglyceride were measured by automatic biochemistry analyzer. All 6 tag single nucleotide polymorphisms (tagSNPs) within ADD1 gene were genotyped by SNPstream genotyping system. Multifactor dimensionality reduction (MDR) was used to identify the interactions among the SNPs and the non-genetic factors. Results showed that plasma triglyceride, total cholesterol, and BMI were significantly higher in the hypertensive group than in the control group. Result from genotyping indicated that rs4963 was significantly associated with essential hypertension. After stratification by gender, rs4963 was associated with essential hypertension only in males. MDR analysis indicated that interaction among BMI, rs4963, and rs16843452 were involved in susceptibility of hypertension. The present study indicated that rs4963 within ADD1 gene was associated with essential hypertension in Chinese population, which might be related to altered exonic splicing and disrupted gene regulation.

The ACE I/D polymorphism in US adults: limited evidence of association with hypertension-related traits and sex-specific effects by race/ethnicity

BACKGROUND

The insertion/deletion (I/D) variant (rs4646994) of the angiotensin I-converting enzyme (ACE) gene is one of the most studied polymorphisms in relation to blood pressure and essential hypertension in humans. The evidence to date, however, on an association of this variant with blood pressure-related outcomes has been inconclusive.

METHODS

We examined 5,561 participants of the Third National Health and Nutrition Examination Survey (NHANES III), a population-based and nationally representative survey of the United States, who were ≥20 years of age and who self-identified as non-Hispanic white, non-Hispanic black, or Mexican American. Within each race/ethnicity, we assessed genetic associations of the I/D variant with systolic blood pressure (SBP), diastolic blood pressure (DBP), and hypertension, as well as genotype-sex interactions, in four genetic models (additive, dominant, recessive, and codominant).

RESULTS

The frequency of the I/D variant differed significantly by race/ethnicity (P = 0.001). Among non-Hispanic blacks, the D allele was significantly associated (P < 0.05) with increased SBP in additive and dominant covariate-adjusted models and was also associated with increased DBP in dominant models when participants taking ACE inhibitors were excluded from the analyses. No other significant associations were observed in any race/ethnic group. Significant genotype-sex interactions were detected among Mexican Americans, for whom positive associations with SBP and hypertension were seen among females, but not males.

CONCLUSIONS

This study gives limited support for association of the ACE I/D variant with blood pressure and for sex-specific effects among particular race/ethnic groups, though we cannot rule out the role of genetic or environmental interactions.

α-Adducin Gly460Trp gene mutation and essential hypertension in a Chinese population: a meta-analysis including 10,960 subjects

Background

The α-adducin Gly460Trp (G460W) gene polymorphism may be associated with susceptibility to essential hypertension (EH), but this relationship remains controversial. In an attempt to resolve this issue, we conducted a meta-analysis.

Methods

Twenty-three separated studies involving 5939 EH patients and 5021 controls were retrieved and analyzed. Four ethnicities were included: Han, Kazakh, Mongolian, and She. Eighteen studies with 5087 EH patients and 4183 controls were included in the Han subgroup. Three studies with 636 EH patients and 462 controls were included in the Kazakh subgroup. The Mongolian subgroup was represented by only one study with 100 EH patients and 50 controls; similarly, only one study with 116 EH patients and 326 controls was available for the She subgroup. The pooled and ethnic group odds ratios (ORs) along with the corresponding 95% confidence intervals (95% CI) were assessed using a random effects model.

Results

There was a significant association between the α-adducin G460W gene polymorphism and EH in the pooled Chinese population under both an allelic genetic model (OR: 1.12, 95% CI: 1.04–1.20, P = 0.002) and a recessive genetic model (OR: 1.40, 95% CI: 1.16–1.70, P = 0.0005). In contrast, no significant association between the α-adducin G460W gene polymorphism and EH was observed in the dominant genetic model (OR: 0.88, 95% CI: 0.72–1.09, P = 0.24). In stratified analysis by ethnicity, significantly increased risk was detected in the Han subgroup under an allelic genetic model (OR: 1.13, 95% CI: 1.04–1.23, P = 0.003) and a recessive genetic model (OR: 1.43, 95% CI: 1.17–1.75, P = 0.0006).

Conclusions

In a Chinese population of mixed ethnicity, the α-adducin G460W gene polymorphism was linked to EH susceptibility, most strongly in Han Chinese.

Association of α-adducin and G-protein β3 genetic polymorphisms with hypertension: a meta-analysis of Chinese populations

Background

Mounting evidence has suggested that α-adducin and G-protein β3 (GNB3) genes are logical candidates for salt-sensitive hypertension. Some, but not all, studies have reported that α-adducin G460T and GNB3 C825T polymorphisms may influence the risk of the disease. To comprehensively address this issue, we performed a meta-analysis to evaluate the influence of these two polymorphisms on hypertension and potential biases in Chinese.

Methods

Data were analyzed using Stata (v11.0) and random-effects model was applied irrespective of between-studies heterogeneity, which was evaluated via subgroup and meta-regression analyses. Study quality was assessed in duplicate. Publication bias was weighed using Egger's test and funnel plot.

Results

36 study populations totaling 9042 hypertensive patients and 8399 controls were finally identified. Overall, in allelic/genotypic/dominant/recessive models, no significant association was identified for both G460T and C825T polymorphisms (P>0.05) and there was possible heterogeneity (I²>25%). Subgroup analyses by study design indicated that the magnitude of association in population-based studies was marginally significantly strengthened for α-adducin G460T allelic model (OR = 1.12; 95% CI: 1:00–1.25; P = 0.043). Moreover, subgroup analyses by geographic distribution indicated comparison of 825T with 825C yielded a marginally significant increased risk in southern Chinese only (OR = 1.48; 95% CI: 1.01–2.16; P = 0.045). Further meta-regression analyses showed that geographic regions were a significant source of between-study heterogeneity for both polymorphisms. There was a possibility of publication bias for G460T, but not for C825T.

Conclusions

Our overall results suggest null association of α-adducin G460T and GNB3 C825T polymorphisms with hypertension in Chinese but indicate local marginal significance of C825T, as a putative salt-sensitive switch, in southern Chinese.

α-adducin Gly460Trp polymorphism and essential hypertension risk in Chinese: a meta-analysis

No clear consensus has been reached on the α-adducin polymorphism (Gly460Trp) and essential hypertension (EH) risk in Chinese. We conducted a meta-analysis in an effort to systematically explore the possible association. Case-control studies in Chinese and English performed with human subjects were identified by searching the MEDLINE, EMBASE, China Biological Medicine Database, China National Knowledge Infrastructure platform, Wanfang and VIP databases. The fixed-effects model and the random-effects model for dichotomous outcomes were applied to combine the results of the individual studies. We selected 20 studies that met the inclusion criteria, including a total of 5562 patients with hypertension and 4289 controls. Overall, our findings supported the hypothesis that the ADD1 Gly460Trp polymorphism is associated with EH in the Chinese population. A borderline association was found between the tryptophan (Trp) allele of the Gly460Trp variant and hypertension (P=0.05, Odds ratio (OR)=1.08, 95% confidence interval (CI)=1.00-1.17 and P(heterogeneity)=0.02). Significantly increased risk was observed in the recessive genetic model (P=0.0009, OR=1.24, 95% CI=1.09-1.41 and P(heterogeneity)=0.04) as well as in the homozygote comparison (P=0.006, OR=1.25, 95% CI=1.07-1.46 and P(heterogeneity)=0.03). Furthermore, in the subgroup analysis, our results support a positive association among Chinese Han individuals (P=0.001, OR=1.25, 95% CI=1.09-1.42, P(heterogeneity)=0.08, recessive genetic model; P=0.009, OR=1.26, 95% CI=1.06-1.50, P(heterogeneity)=0.03, homozygote comparison). No apparent association was identified in Kazakhs. Our meta-analysis suggests that the Gly460Trp polymorphism might increase the risk of hypertension in Chinese populations, especially in Han Chinese. Further studies investigating gene-gene, gene-environment and mutual interactions are needed to better understand the role of ADD1 in hypertension.