Neonatal lupus erythematosus, multiple thromboses, and monoarthritis in a family with Ro antibody.

We describe a family afflicted with striking clinical and serologic autoimmune features. The mother and maternal uncle of a patient with neonatal lupus had rheumatic disease manifestations. All three had Ro antibodies (SS-A) in their sera, as well as La antibody (SS-B). The 17-year-old mother developed postpartum inflammatory monoarthritis of the right knee and had a positive lupus band test. The uncle at the age of 26 developed a fulminant disease most consistent with systemic lupus erythematosus (SLE); initial manifestations were myocardial infarction, deep vein thrombosis, and the nephrotic syndrome. Although it is known that mothers of neonatal lupus infants can develop SLE postpartum, the development of severe disease in the maternal uncle suggests the relevance of identifying seropositive relatives of individuals with neonatal lupus.