Objective: To identify the novel genetic determinants in patients with congenital heart disease (CHD).
Methods: The clinical data and peripheral venous blood samples from 120 unrelated individuals with idiopathic CHD were collected and evaluated compared to 100 unrelated healthy controls. The complete coding exons and the partial flanking introns of GATA4 gene were amplified by polymerase chain reaction and sequenced by di-deoxynucleotide chain termination. The generated sequences were aligned with those retrieved from GenBank with the aid of programme BLAST to identify the sequence variations. The software Clustal W was utilized to analyze the conservation of altered amino acids.
Results: Three novel heterozygous missense GATA4 mutations were identified in 3 of 120 CHD cases. Namely, the triplet substitutions of AGA for AGC at codon 90, GAG for GAC at codon 95, and AAT for AAG at codon 329, predicting the conversions of serine into arginine at amino acid residue 90 (S90R), aspartic acid into glutamic acid at amino acid residue 95 (D95E) and lysine into asparagine at amino acid residue 329 (K329N), were detected. None of these three mutations were probed in 100 controls. A cross-species alignment of GATA4 encoded protein sequences displayed that the lysine at amino acid residue 329 was completely conserved evolutionarily. Additionally, a single nucleotide polymorphism c. 99G>T was observed. However, the polymorphic frequency distribution in CHD patients was not statistically different from that in controls (for genotypes, chi(2) = 0.2640, P = 0.6074; for alleles, chi(2) = 0.2514, P = 0.6161).
Conclusion: The idiopathic CHD has a marked heterogeneity and the mutated GATA4 gene may be responsible for CHD in a subset of patients.