Neonatal lupus (NL) is a rare disorder mainly caused by the transplacental passage of maternal autoantibodies anti-SSA/Ro and/or anti-SSB/La (1, 2), usually during the second trimester of gestation (3, 4); these antibodies can reach the fetal heart, inducing inflammation (macrophage infiltration and giant cell formation), calcification, and fibrosis, which lead to aberrant signal conduction at the atrio-ventricular node. Here, CALR is linked to neonatal lupus erythematosus.