Childhood scleromyositis with a negative PM/Scl antibody.

Overlap syndromes, such as scleromyositis, antisynthetase syndrome and mixed connective tissue disease, consist of a blend of clinical features involved in two separate autoimmune disorders. Scleromyositis, the most common overlap syndrome, is usually observed in adults, and has rarely been documented in childhood. Here, the case of a 10-year-old African American female with scleromyositis is reported. This disease has features of both dermatomyositis and systemic scleroderma. Her disease process began with signs and symptoms of dermatomyositis and slowly changed clinically to features of systemic scleroderma. This patient had a positive ANA with a nucleolar pattern and a negative anti-PM/Scl antibody, an antibody which has been used as a prognostic and diagnostic marker of scleromyositis.