NEONATAL LUPUS-ERYTHEMATOSUS - DISCORDANT DISEASE EXPRESSION OF U(1)RNP-POSITIVE ANTIBODIES IN FRATERNAL-TWINS - IS THIS A SUBSET OF NEONATAL LUPUS-ERYTHEMATOSUS OR A NEW DISTINCT SYNDROME

Neonatal lupus erythematosus (NLE) is an uncommon disease that is mani fested by cutaneous lesions, cardiac conduction defects, or both, that appear in utero or shortly after birth. In approximately 95% of patie nts, anti-Ro antibody (Ro[SS-A]) has been identified and has become th e serologic marker for NLE. Since 1987 there have been four reported c ases of Ro- and anti-La antibody (La[SS-B])-negative, U(1)RNP antibody -positive, NLE. Our affected twin, as well as all other infants with U (1)RNP-positive NLE, had cutaneous lesions similar to those in Ro-posi tive NLE, although they lacked systemic abnormalities, including cardi ac conduction defects. HLA typing of mothers with infants with U(1)RNP -positive NLE revealed the presence of HLA-DR4, DQw1, or DQw3 phenotyp es. Our typing confirms these findings. As with Ro-positive NLE, no di stinct HLA associations were demonstrated in the infants. Unlike Ro-po sitive mothers, all mothers with a U(1)RNP-positive infant with NLE ha d connective tissue disease at the time of the diagnosis and had a dif ferent spectrum of disease. We describe the clinical, serologic, and i mmunogenetic findings in the first reported case of U(1)RNP-positive N LE in dizygotic twins in whom the NLE disease expression was discordan t.