Pulmonary hypertension in a child with mixed connective tissue disease.

Mixed connective tissue disease (MCTD) is characterized by high titers of antibody to ribonucleoprotein (RNP) in patients with features of several rheumatic diseases. We describe a child whose MCTD included arthritis, Raynaud's phenomenon, mucocutaneous ulcerations, sclerodermatous skin changes, restrictive lung disease, reduced carbon monoxide pulmonary diffusing capacity, abnormal esophogeal motility, and severe pulmonary hypertension. High antibody titers to ds-DNA and RNP were present. Clinical improvement followed therapy with prednisone and cyclophosphamide. Improvement in the degree of pulmonary hypertension was documented by repeat cardiac catheterization 8 months after the initiation of combination therapy.