Familial IgG subclass imbalance, anti-SS-A antibodies and third-trimester foetal death

Foetal heart block occurred in the second pregnancy of an apparently healthy 23-yr-old woman. Her mother and sister were known for 10 yr with hypergammaglobulinaemia which was due to a disproportionate polyclonal elevation of serum IgG1 and with a high titre of rheumatoid factors. No associated disease was obvious. A third-trimester foetal death had occurred with each of these patients. In the sera of these three women circulating anti-SS-A (Ro) antibodies were detected, which are known to be associated with congenital heart block. IgG subclass imbalance, consisting of a disproportionate polyclonal elevation of IgG1, has been recognised as being associated with a characteristic autoantibody pattern. Familial occurrence of this syndrome as such has hitherto not been reported.