A novel variant in TBX20 (p.D176N) identified by whole-exome sequencing in combination with a congenital heart disease related gene filter is associated with familial atrial septal defect

Congenital heart disease (CHD) is the leading cause of birth defects, and its etiology is not completely understood. Atrial septal defect (ASD) is one of the most common defects of CHD. Previous studies have demonstrated that mutations in the transcription factor T-box 20 (TBX20) contribute to congenital ASD. Whole-exome sequencing in combination with a CHD-related gene filter was used to detect a family of three generations with ASD. A novel TBX20 mutation, c.526G>A (p.D176N), was identified and co-segregated in all affected members in this family. This mutation was predicted to be deleterious by bioinformatics programs (SIFT, Polyphen2, and MutationTaster). This mutation was also not presented in the current Single Nucleotide Polymorphism Database (dbSNP) or National Heart, Lung, and Blood Institute (NHLBI) Exome Sequencing Project (ESP). In conclusion, our finding expands the spectrum of TBX20 mutations and provides additional support that TBX20 plays important roles in cardiac development. Our study also provided a new and cost-effective analysis strategy for the genetic study in small CHD pedigree.