The familial form in primary pulmonary hypertension is inherited as an autosomal dominant trait and is associated with a pattern of "genetic anticipation", a worsening of disease in subsequent generation, manifestated by greater severity or earlier onset. Familial primary pulmonary hypertension acounted for 6 percent of the 187 cases in the NIH registry. But, there is no reported case on Korea. We report on 25 years old woman who had PPH presenting with exertional dyspnea and dry coughing during second baby pregnancy and whose brother dies of PPH in other Hospital. Her simple chest X ray, 2-D Echocardiography, pulmonary angiogram and cardiac catheterization findings were compatible with typical primary pulmonary hypertension. Pulmonary function test was normal and perfuion lung scan had no evidence of pulmonary thromboembolism. There was no evidence of connective tissue diseases including SLE, RA, polymyositis and dermatomyositis and so on in the laboratory findings. Her younger brother had been admitted to other hospital due to aggravation of dyspnea, progressing slowly for 3 years and his case diagnosed as PPH through echocardiography, cardiac catheterrization, open lung biopsy and so on.