TNNT2 gene polymorphisms are associated with susceptibility to idiopathic dilated cardiomyopathy in the Han Chinese population

TNNT2 Gene Polymorphisms are Associated with Susceptibility to Idiopathic Dilated Cardiomyopathy in Kazak and Han Chinese

Background

Dilated cardiomyopathy (DCM) is characterized by left ventricular enlargement, systolic dysfunction, and heart failure. Both genetic and non-genetic factors have been linked to DCM pathogenesis. Familial DCM (FDCM) accounts for 20%–50% of all DCM cases, highlighting the importance of genetics in pathogenesis. Indeed, more than 40 DCM-associated genes have been identified, including the gene encoding cardiac troponin T type-2 (TNNT2). We examined polymorphisms of the TNNT2 gene in idiopathic DCM (IDCM) patients of Kazak and Han ethnicity compared with healthy Kazak and Han controls.

Material/Methods

Peripheral blood samples were collected from 180 patients with IDCM (90 Kazak and 90 Han), and 180 healthy controls (90 Kazak and 90 Han). PCR was used to amplify 15 exons and nearby introns of the TNNT2 gene. The amplified products were sequenced and compared to the standard sequence in PubMed by BLAST and CHROMAS software, to identify mutation sites.

Results

Results from Kazak and Han IDCM patients were complied for Hardy-Weinberg equilibrium analysis. There was a significant difference in the genotype distribution (χ²=6.67, P=0.015) and allele frequency (χ²=5.71, P=0.017) between Kazaks with IDCM and Kazak controls of SNP rs3729547. There was also a difference in the genotype distribution (χ²=6.62, P=0.036) and allele frequency (χ²=4.91, P=0.018) between Han with IDCM and Han controls. The TNNT2 gene polymorphism loci rs3729547 may be associated with the IDCM onset in Kazak and Han patients (OR=2.5, 95% CI: 1.233~5.068).

Conclusions

The TNNT2 polymorphisms might play an important role in susceptibility to DCM in Xinjiang Kazak and Han patients.

Cardiac troponin T (TNNT2) mutations in chinese dilated cardiomyopathy patients

BACKGROUND

Dilated cardiomyopathy (DCM) is one of the leading causes of heart failure with high morbidity and mortality. Although more than 40 genes have been reported to cause DCM, the role of genetic testing in clinical practice is not well defined. Mutations in the troponin T (TNNT2) gene represent an important subset of known disease-causing mutations associated with DCM. Therefore, the aim of the present study was to determine the genetic variations in TNNT2 and the associations of those variations with DCM in Chinese patients.

METHODS

An approximately 4 kb fragment of the TNNT2 gene was isolated from 103 DCM patients and 192 healthy controls and was analyzed by DNA sequence analysis for genetic variations.

RESULTS

A total of 6 TNNT2 mutations were identified in 99 patients, including a G321T missense mutation (Leu84Phe) and 5 novel intronic mutations. Alleles of two novel SNPs (c.192 + 353 C>A, OR = 0.095, 95% CI: 0.013-0.714, P = 0.022; c.192 + 463 G>A, OR = 0.090, 95% CI: 0.012-0.675, P = 0.019) and SNP rs3729843 (OR = 1.889, 95% CI: 1.252-2.852; P = 0.002) were significantly correlated with DCM.

CONCLUSIONS

These results suggest that the missense mutation (Leu84Phe) and two novel SNPs (c.192 + 353 C>A, c.192 + 463 G>A) in TNNT2 gene might be associated with DCM in the Chinese population.