What is the definition or description of: neonatal lupus?

Baby Lupus: Neonatal lupus erythematosus presents in infants, most often girls, born to mothers who carry the ro/ssa antibody. Neonatal lupus can cause a decrease in red cells (anemia), white blood cells and platelets, and a skin rash. Problems can also develop in the electrical system of the baby's heart (congenital heart block). A pacemaker for the baby's heart may be needed in this setting.

Autoimmune disease: Neonatal lupus is a passively transferred autoimmune disease. It occurs in ~1-2% of babies born to mothers with autoimmune disease, primarily systemic lupus erythematosus and sjögren’s syndrome, and antibodies to ssa/ro and/or ssb/la. Many cases occur in children of mothers who have the same autoantibodies, but who do not have symptoms of lupus or other autoimmune diseases.