title: Primary pulmonary hypertension occurring in twins.
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D004200:Diseases in Twins; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000235:genetics*; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic