CALR and congenital heart block: The risk for congenital heart block (CHB) is ~ 1%–2%, in cases of maternal positivity for anti SS-A/Ro and/or anti SS-B/La antibody, but rises to almost 18% in cases with a history of CHB in a prior pregnancy (Brito-Zeron, Izmirly, Ramos-Casals, Buyon, & Khamashta, 2015) [5].