TRIM21 and atrioventricular block: Anti-Ro/SSA antibodies can cross the placenta as early as 11 weeks of gestation and cause inflammation, fibrosis, and calcification of the conduction system leading to AV block, cardiomyopathy, valvulitis, endocardial fibroelastosis, pericardial effusion, and hydrops (Figure 12, Figure 13 and Figure 14); extranodal disease often coincides or heralds the development of AV block but may occur in its absence [83,84,85].