Atrial, sinoatrial node and atrioventricular node disease with preserved conductivity results in tachy-bradycardia syndrome.(1) Tachy-bradycardia syndrome has been reported in fetuses with the missense variant p.(Gly482Arg) in HCN4 gene.(2) Atrial ectopics and junction ectopic tachycardia were reported in fetuses with autoimmune atrioventricular block.(3,4) An unusual dominant involvement of sinoatrial node in a fetus presenting with tachy-bradycardia syndrome of Anti-SSA/SSB-Positive mother.