Even asymptomatic mothers with slow fetal heart rate and echocardiographic findings of heart block should also be tested for the presence of these antibodies, as it is not unusual for neonatal lupus to be the first clue toward the detection of anti-Ro/SSA and anti-La/SSB antibodies (see also the clinical case report and Table 1). This evidence concerns the gene TRIM21 and neonatal lupus erythematosus.