Mutations Analysis Of TBX1 Gene In Chinese Patients With Congenital Heart Defects

Objective To investigate the mutations of TBX1 gene in Chinese patients with congenital heart defects(CHD) and to study the relationship between mutations of TBX1 gene and nonsyndromic CHD.Methods Polymerase chain reaction -single stranded conformation polymorphism (PCR-SSCP) analysis was performed to screen for mutations of TBX1 gene in 73 individuals with CHD and 70 healthy individuals. 1) Genomic DNA was extracted from the peripheral leukocytes of each individual using the phenol-chloroform method. 2) PCR was performed with genomic DNA from each individual on all the axons in TBX1 coding regions. 3) PCR products were screened by single-strand conformation polymorphism analysis. 4) The changes observed by SSCP were further confirmed by sequencing analysis of the PCR product. 5) We usedχ2 analysis to assess for significance in the frequency of the TBX1 sequence variations.Results 928G→A and 933A→G sequence variations were detected in both individuals with CHD and healthy individuals. One homozygosis 928G→A sequence variations and eight heterozygous 928G→A sequence variations were found in 73 individuals with CHD,as well as 23 homozygosis 933A→G sequence variations and 2 heterozygous 933A→G sequence variations.4 heterozygous 928G→A sequence variations ,22 homozygosis 933A→G sequence variations and 2 heterozygous 933A→G sequence variations were found in 70 healthy individuals. No significant difference was observed in frequencies of the sequence variations between individuals with CHD and control subjects(928G→A:χ2=1.89,P > 0.05;933A→G:χ2=2.43×10-5,P > 0.05).Conclusion TBX1 mutations are not likely to play a major role in nonsyndromic CHD.