Abstract
BackgroundConotruncal heart defect (CTD) is a complex congenital heart disease with a complex and poorly understood etiology. The transcriptional corepressor RIPPLY3 plays a pivotal role in heart development as a negative regulator of the key cardiac transcription factor TBX1. A previous study showed that RIPPLY3 contribute to cardiac outflow tract development in mice, however, the relationship between RIPPLY3 and human cardiac malformation has not been reported.Methods615 unrelated CTD Chinese Han patients were enrolled, we excluded the 22q11.2 deletion/duplication using a modified multiplex ligation-dependent probe amplification method—CNVplex®, and investigated the variants of RIPPLY3 in 577 patients without the 22q11.2 deletion/duplication by target sequencing. Functional assays were performed to testify the potential pathogenicity of nonsynonymous variants found in these CTD patients.ResultsFour rare heterozygous nonsynonymous variants (p.P30L, p.T52S, p.D113N and p.V179D) were identified in four CTD patients, the variant NM_018962.2:c.155C>G (p.T52S) is referred as rs745539198, and the variant NM_018962.2:c.337G>A (p.D113N) is referred as rs747419773. However, variants p.P30L and p.V179D were not found in multiple online human gene variation databases. Western blot analysis and immunofluorescence showed that there were no significant difference between wild type RIPPLY3 and these four variants. Luciferase assays revealed that the p.T52S variant altered the inhibition of TBX1 transcriptional activity in vitro, and co-immunoprecipitation assays showed that the p.T52S variant reduced the physical interaction of RIPPLY3 with TBX1. In addition to the results from pathogenicity prediction tools and evolutionary protein conservation, the p.T52S variant was thought to be a potentially deleterious variant.ConclusionOur results provide evidence that deleterious variants in RIPPLY3 are potential molecular mechanisms involved in the pathogenesis of human CTD.
Highlights
Conotruncal heart defect (CTD) is a complex congenital heart disease with a complex and poorly understood etiology
Conotruncal heart defect (CTD) is a severe malformation. It is characterized by a disordered orchestration of the ventricles, the aorta and the pulmonary artery, and consists of the tetralogy of Fallot (TOF), transposition of the great arteries (TGA), double outlet of right ventricle (DORV), persistent truncus arteriosus (PTA), pulmonary atresia with ventricular septal defect (PA/VSD), and interrupted aortic arch (IAA)
Four missense variants of RIPPLY3 were identified in 22q11.2 copy number variant (CNV)‐negative patients Four heterozygous missense variants in RIPPLY3 were identified in 4 unrelated CTD patients out of the 577 CTD patients without 22q11.2 deletion/duplication, all the variants were absent from the 391 controls in our cohort: p.P30L in TOF, p.T52S in TOF, p.D113N in TGA/ PA/VSD, and p.V179D in PA/VSD and patent ductus arteriosus (PDA) (Table 2)
Summary
Conotruncal heart defect (CTD) is a complex congenital heart disease with a complex and poorly understood etiology. Congenital heart disease (CHD), including heterogeneous anatomy with distinct phenotypic subtypes, is the most common form of birth defect in humans, and it affects approximately 1% of all live births [1, 2]. Conotruncal heart defect (CTD) is a severe malformation. CTD is estimated to occur in approximately 1 out of 1000 live births [3]. It is the most common cyanosis CHD, and it usually requires surgical treatment. Patients born with CTD often need lifelong specialized cardiac care
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
