Any primary pulmonary hypertension in which the cause of the disease is a mutation in the KCNK3 gene. The disease is pulmonary hypertension, primary, 4 (MONDO_0014136). Also known as: KCNK3 primary pulmonary hypertension, primary pulmonary hypertension caused by mutation in KCNK3, pulmonary hypertension, primary, type 4.