FAMILIAL SCLERODERMA - EVIDENCE FOR ENVIRONMENTAL VERSUS GENETIC TRIGGER

Families with more than one case of scleroderma are unusual. Four fami lies each with two members (in one case monozygotic twins) with sclero derma (systemic sclerosis, SSc) were identified. Clinical, immunogenet ic and autoantibody studies were carried out. Multicase SSc families c ited in the literature were reviewed. Each family pair shared cutaneou s subset of disease severity, and SSc-associated autoantibody. HLA typ ing showed two pairs shared an HLA-DR allele associated with scleroder ma (DR3 or DR5), while one also had alleles reported in association wi th their SSc-specific autoantibody. Review of dates and ages of onset suggested that the timing of onset of scleroderma is more likely to ha ve an environmental trigger than to be encoded genetically.