Objective: To investigate the germline mutations of the CHD7 gene and their roles in patients with congenital heart disease (CHD).
Methods: Genomic DNAs extracted from peripheral blood were subjected to screen mutations in CHD7 gene by denaturing high performance liquid chromatography (DHPLC) followed by DNA sequencing of aberrant peaks in 67 CHD patients and 100 healthy control. Case-control study and bioinformatic analysis were utilized to explore the potential functional roles of the variations detected.
Results: Seven kinds of single nucleotide substitution were detected in the CHD patients in different introns of the CHD7 gene. Among them, IVS11+ 127A to G and IVS12+ 21T to G were rare variations and the allele frequencies of both were 0.0075; while IVS2+ 34G to A, IVS4+ 39G to A, IVS12-5T to C and IVS16+ 51C to A were the single nucleotide polymorphisms and the allele frequency was 0.2635, 0.2156, 0.1505 and 0.3636 respectively. The frequency of IVS12-5T to C in the CHD group was significantly lower than that in the control group (5.42%versus 9.57%, P< 0.05). The variant of IVS14-35C to G was only detected in patients with CHD. Bioinformatic analysis showed that IVS12-5T to C might increase exon splicing ability comparing with the wild-type sequence.
Conclusion: The CHD7 gene mutation may not be the main reason for sporadic congenital heart disease, whereas the single nucleotide polymorphism of IVS12-5T to C might play a protective role in the onset of this disease.