In primary pulmonary hypeension basic abnormality in gene lies in
**Core Concept**
Primary pulmonary hypertension (PPH) is a rare and idiopathic disorder characterized by elevated pulmonary artery pressure without any obvious cause. The underlying pathophysiology involves abnormal cellular proliferation and remodeling of the pulmonary arterial wall, leading to increased vascular resistance and pulmonary hypertension.
**Why the Correct Answer is Right**
The basic abnormality in PPH lies in the bone morphogenetic protein receptor type 2 (BMPR2) gene. Mutations in the BMPR2 gene lead to the development of PPH by promoting excessive cellular proliferation and inhibiting apoptosis in pulmonary artery smooth muscle cells. This results in the formation of abnormal muscularized and non-muscularized pulmonary arteries, contributing to the pathogenesis of PPH. The BMPR2 gene plays a crucial role in regulating the TGF-β signaling pathway, which is involved in vascular remodeling and proliferation.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because mutations in the BMPR2 gene are not the only genetic cause of PPH. While BMPR2 mutations are the most common genetic cause, other genes such as ALK1 and ENG are also implicated in the development of PPH.
**Option B:** This option is incorrect because the basic abnormality in PPH is not related to the renin-angiotensin-aldosterone system (RAAS). While RAAS is involved in the pathogenesis of secondary pulmonary hypertension, it is not the primary cause of PPH.
**Option C:** This option is incorrect because the basic abnormality in PPH is not related to the endothelin system. While endothelin-1 is involved in the pathogenesis of pulmonary hypertension, it is not the primary cause of PPH.
**Option D:** This option is incorrect because the basic abnormality in PPH is not related to the prostacyclin system. While prostacyclin is involved in the pathogenesis of pulmonary hypertension, it is not the primary cause of PPH.
**Clinical Pearl / High-Yield Fact**
PPH is a rare but severe disorder, and early diagnosis is crucial to prevent progression to right heart failure. The presence of BMPR2 mutations can be used as a diagnostic marker for PPH, and genetic testing is recommended for patients with a family history of PPH.
**Correct Answer: C. BMPR2 gene.**