EPHB4 and Abnormal cardiac septum morphology: We previously reported that monoallelic missense variants in the intracellular tyrosine kinase domain of EPHB4 cause a form of in utero primary lymphatic anomaly coined lymphatic-related fetal hydrops with/without atrial septal defect (LRFH) (OMIM 617300).2 The study included two families (GLDUK and GLDNOR) with a primarily lymphatic and venous phenotype, but with several family members presenting with fetal hydrops and/or atrial septal defects (ASD).