Drs. Julkunen and Eronen's report (1) on the high prevalence of “autoimmune” clinical symptoms (especially sicca syndrome) in mothers of children with congenital heart block (HB) is an additional contribution to the somewhat confusing distinction between congenital and acquired HB (2). In their study, mothers of children with HB detected after the newborn period did not have clinical features of autoimmune diseases (1). Serologic differences between these 2 groups are well known: maternal antibodies to Ro/SSA are essential for congenital HB (3, 4), whereas most of the mothers of children in the acquired HB group are seronegative, suggesting 2 forms of HB in children (5).
Anti-Ro/SSA–positive mothers of children with postnatally detected HB with (2, 6) or without (5, 7) clinical symptoms of an autoimmune disorder are difficult to categorize. The anti-Ro/SSA status of the mothers studied by Julkunen and Eronen was not reported, and this element could add to our understanding on the subject. In a previous study from the same group (8), all 33 mothers of children with congenital HB were found to be anti-Ro/SSA positive and the clinical findings were similar to those reported in the comparable group in the present study (1). However, in that former study, no mothers of children with “late onset” HB were serologically studied.