While the reactivity of sera with the whole proteins Ro52, Ro60 and La was high in subgroups of SLE and SS mothers and did not help to distinguish the group of mothers at risk, the overall level of IgG antibodies reacting with several Ro peptides, however, was significantly higher in lupus mothers of group I as compared with group II. This evidence concerns the gene RO60 and systemic lupus erythematosus.