According to serum parathyroid hormone level, we divided our patients in three groups, patients with normal serum iPTH level (150-300 pg/mL), patients with high serum parathyroid hormone level (higher than 300 pg/mL) and patients with low serum parathyroid hormone level (lower than 150 pg/mL) and then evaluated the relationship of these groups with PHT with use of Pearson’s test. The gene discussed is PTH; the disease is pulmonary hypertension, primary, 1.