The epidemiology and genetic basis of common diseases

Association of with-no-lysine kinase 1 and Serine/Threonine kinase 39 gene polymorphisms and haplotypes with essential hypertension in Tibetans

Tibetans have a higher essential hypertension prevalence compared with other ethnics in China. The reason might be due to their unique environmental influence, as well as genetic factor. However, limited studies focus on Tibetan genetics and its association with hypertension. The aim of this study was to investigate the association between With-No-Lysine (K) Kinase 1 (WNK1), Serine/Threonine kinase 39(STK39) genes variants and hypertension in the Tibetan population. 204 Tibetan hypertensive patients and 305 normotensive controls were recruited in an epidemiological survey conducted at 2 sites in the Ganzi Tibetan autonomous region. Patients were genotyped for nineteen WNK1 candidate tag single nucleotide polymorphisms (SNPs) and three STK39 SNPs, and haplotype analysis was performed. Results showed that the allele A in rs1468326 was overrepresented in hypertensive patients versus control (53.4% vs 42.9%, P < 0.05). The multivariable-adjusted odds ratio (OR) for hypertension among CA + AA genotypes carriers was 1.60 (95% CI: 1.02-2.62, P < 0.05), and they also had a higher systolic blood pressure (136.5 ± 28.6 vs 131.7 ± 24.8 mmHg, P < 0.05). However, the TT genotype ratio in rs6749447 was lower in hypertensives (5.4% vs 10.8%, P < 0.05), and the hypertension risk for the TT genotype carriers in rs6749447 decreased after adjustment (OR 0.49, 95% CI 0.19-0.95, P < 0.05). Subjects with haplotype AGACAGGAATCGT showed 1.57 times higher risk of hypertension (95% CI 1.02-2.41, P < 0.05). In conclusion, SNP rs1468326 of WNK1, rs6749447 of STK39, and WNK1 haplotype AGACAGGAATCGT were associated with hypertension in Tibetan individuals. Environ. Mol. Mutagen. 59:151-160, 2018. © 2017 Wiley Periodicals, Inc.

Mucin genes in gallstone disease

Gallstone disease is a complex disorder that can be caused by environmental influences, common genetic factors and their interactions. Three major pathogenic abnormalities are considered to involve in gallstone formation: cholesterol supersaturation in bile, precipitation and nucleation of excess cholesterol, and gallbladder hypomotility, while, mucin takes part in the cholesterol nucleation process. Up to date, more than 20 mucin genes have been reported, 9 of them are identified at the mRNA and/or protein level in native gallbladder and its associated diseases. In the gallbladder, mucin is essential for best protection against detergent effect of high concentration of bile acids. Over the past decade, the properties, expressions and functions of the gallbladder mucins are delineated in animal and human studies. Alteration expressions of mucins are thought to response during the pathogenesis of gallstone formation. Moreover, recent genetic association study demonstrated mucin gene polymorphisms may also influence susceptibility to gallstone disease. This review is not to provide a complete coverage of all the aspects of mucin glycoproteins, but focus on the role and expression of mucins involve in the regulation of cholelithogenesis.

Polymorphism at the mucin-like protocadherin gene influences susceptibility to gallstone disease

BACKGROUND

Gallstone disease (GSD) is a common disease that can be caused by environmental influences, common genetic factors and their interactions. Mucin glycoproteins may be one important factor for GSD. We conducted a case-control study to investigate the relationship between the mucin-like protocadherin (MUPCDH) gene polymorphisms and GSD.

METHODS

The study included 452 GSD cases and 491 healthy controls who had no evidence of gallstones by ultrasound examination. Two common tagging single nucleotide polymorphism (SNP) rs3758650 and rs7932167, and four non-synonymous SNPs rs34362213, rs2740375, rs7108757 and rs2740379 were genotyped. The genetic effects were evaluated using the multivariate regression model.

RESULTS

The genotypes of these SNPs were all in Hardy-Weinberg equilibrium. Three non-synonymous SNPs (rs34362213, rs7108757 and rs2740379) were monomorphic. The single SNP analysis showed two SNPs (rs7932167 and rs2740375) were not associated with GSD and only SNP rs3758650 had the association of the presence of GSD with an odds ratio (OR) of 1.59 (adjusted P=0.013) for the AG genotype and 5.82 (adjusted P=0.007) for the AA genotype when compared with the reference GG genotype. The haplotype analysis of the three polymorphic SNPs showed GCA was significant for GSD (adjusted p=0.001) with an odds ratio (OR) of 1.41 when compared to other haplotypes.

CONCLUSIONS

The MUPCDH genetic polymorphism rs3758650 was considered a genetic marker to predict symptomatic GSD subjects. It may be of importance for GSD patients with the risk SNPs to be frequently checked because they may develop symptomatic GSD.

Association of WNK1 exon 1 polymorphisms with essential hypertension in Hani and Yi minorities of China

The association of polymorphisms in exon 1 of the WNK1 gene with essential hypertension in the minority groups of Hani and Yi of China was investigated in the case-control study. The sequence of 1257bp containing the WNK1 gene exon 1 was determined in 1307 individuals (649 essential hypertension subjects and 658 controls) to identify SNPs in Hani and Yi minority groups. Four of eleven previously known SNPs (rs3168640, rs11885, rs11554421 and rs34880640) were identified. The SNP analysis indicated that SNPs rs11885 and rs11554421 were significantly associated with hypertension in both Hani and Yi populations, and rs34880640 was significantly associated with hypertension in Hani but not in Yi population, adjusted for covariates. Haplotype analysis indicated that the haplotype H1 significantly decreased the risk of hypertension in both populations. These results suggested that WNK1 polymorphisms were involved in the predisposition of essential hypertension in Hani and Yi populations and its effects showed a clear population specificity. This finding supported the importance of population specificity in determining the genetic factors associated with diseases and thus disease treatment.

Multiple mucin genes polymorphisms are associated with gallstone disease in Chinese men

BACKGROUND

Gallstone is a complex disease caused by multiple environmental and genetic factors. One of these is mucin glycoproteins. This case-control study aimed to investigate the association between single nucleotide polymorphisms (SNPs) at the MUC1-4 genes and gallstone.

METHODS

The study included 475 cases and 941 controls. Eight tagging SNPs were selected: one at MUC1, two at MUC2, and five at MUC4. There was no available tagging SNP at MUC3. Genetic effects were initially evaluated by multivariate logistic regression. The combined effects from multiple genes were further evaluated, as well as the sex-specific effect. Permutation was used to correct for multiple testing.

RESULTS

The genotypes were all in Hardy-Weinberg equilibrium. SNP rs7396030 at MUC2 yielded a p value of 0.03. Further sex-specific analysis showed significance solely with male subjects (p=0.005). Similarly, SNP rs4072037 at MUC1 was only significant (p=0.035) in males. The permutation empirical p values were 0.005 for rs7396030 and 0.02 for rs4072037. For males, the combined genetic effect yielded an OR of 4.68 (p=0.0008).

CONCLUSIONS

The SNPs at MUC1 and MUC2 are significantly associated with gallstone in men but not in women. These genes can work jointly to further increase susceptibility to gallstone in a Chinese population.

The genetic basis of diabetes mellitus

Familial risk, pathogenesis, clinical onset, and treatment of diabetes mellitus vary according to etiology. Although Type 2 diabetes has a higher familial risk, more is known about the genetics of Type 1 diabetes. Genes contributing 60% to 65% of susceptibility to Type 1 diabetes mellitus are known. Type 1 diabetes is associated with susceptibility genes in the HLA region on chromosome 6p21 and the insulin gene on chromosome 11p15, and at least eight additional susceptibility genes are under investigation. Islet cytoplasmic antibodies provide humoral evidence of Type 1 diabetes risk. Only 10% of the genes contributing susceptibility to Type 2 diabetes mellitus are known, and they are primarily associated with uncommon subtypes of the disorder. The insulin receptor gene on chromosome 19p13 and at least five glucose transporter genes contribute to Type 2 diabetes susceptibility, and further associations may emerge from study of the glycogen synthase gene, the glucokinase gene, the MODY genes, and the leptin gene. Diabetes comorbidities may result from genetic and environmental susceptibilities independently or in combination.