Numerous mutations in NKX2-5 gene have been reported in CHD patients, including atrial septal defect, ventricular septal defect (VSD) and tetrology of Fallot.
Mutations in NKX2-5 have been found in families showing secundum ASD and atrioventricular (AV) conduction block and in some individuals with tetralogy of Fallot.
Among the available genomic studies, the key findings in Africa were variants in GATA4 (P193H), MTHFR 677TT, and MTHFR 1298CC that were associated with atrial septal defect, ventricular septal defect (VSD), Tetralogy of Fallot (TOF), and patent ductus arteriosus phenotypes and 22q.11 deletion, which is associated with TOF.
The organoids provide a potentially new model for liver regenerative processes, and were used to characterize the effect of different JAG1 mutations that cause: (a) Alagille syndrome (ALGS), a genetic disorder where NOTCH signaling pathway mutations impair bile duct formation, which has substantial variability in its associated clinical features; and (b) Tetralogy of Fallot (TOF), which is the most common form of a complex congenital heart disease, and is associated with several different heritable disorders.
Furthermore, the mutation reduced the synergistic activation between TBX20 and NKX2.5 as well as GATA4, two other transcriptional factors previously associated with various CHD, encompassing TOF.
Furthermore, the mutation significantly decreased the synergistic activation of a downstream target gene between HAND1 and GATA4, another cardiac core transcription factor associated with TOF.
JAG1 mutations have been associated with several disorders including the multi-system dominant disorder Alagille syndrome, and some cases of tetralogy of Fallot (although these may represent variable expressivity of Alagille syndrome).
Variants in the GATA4 gene have been implicated in several congenital heart diseases (CHD), such as the tetralogy of Fallot (ToF), atrial septal defect (ASD), ventricular septal defect (VSD), atrioventricular septal defect (AVSD), and dilated cardiomyopathy (DCM).
The TBX5 variation p.Pro108Thr, located in the T-box domain, was identified in a patient with tricuspid atresia, an exon-intron boundary variation of GATA4 (IVS4+5G>A) was detected in a Tetralogy of Fallot patient and an 8p23 microdeletion was detected in one patient with atrioventricular septal defect and psychomotor delay.
We used primary cells derived from the RV of infants with TOF to show a direct link between scaRNA levels and splice isoforms of several genes that regulate heart development (e.g., GATA4, NOTCH2, DAAM1, DICER1, MBNL1 and MBNL2).
In the developing heart, overexpression of HEY2 is predicted to cause decreased expression of the cardiac transcription factor GATA4 which, in turn, has been shown to cause tetralogy of Fallot.