Genetic risk factor for COPD is
**Core Concept**
Chronic Obstructive Pulmonary Disease (COPD) is a complex disorder influenced by genetic and environmental factors. The genetic susceptibility to COPD is linked to the function and regulation of the lung's defense mechanisms against oxidants and pollutants.
**Why the Correct Answer is Right**
The primary genetic risk factor for COPD is alpha-1 antitrypsin (A1AT) deficiency. A1AT is a serine protease inhibitor produced in the liver and secreted into the bloodstream, where it protects the lungs from tissue damage caused by neutrophil elastase. Deficiency of A1AT leads to uncontrolled elastase activity, resulting in progressive lung damage and COPD. The A1AT gene is located on chromosome 14 and has several variants, with the most common being PiZ, which is associated with severe A1AT deficiency and increased risk of COPD.
**Why Each Wrong Option is Incorrect**
* **Option A:** This is incorrect because the question specifically asks for a genetic risk factor, and option A is not a recognized genetic risk factor for COPD.
* **Option B:** This is incorrect because option B is a common environmental risk factor for COPD, but not a genetic one.
* **Option C:** This is incorrect because option C is a common comorbidity with COPD, but not a genetic risk factor.
**Clinical Pearl / High-Yield Fact**
A1AT deficiency is often asymptomatic until adulthood, when lung damage becomes apparent. Family screening for A1AT deficiency is crucial for early detection and treatment to prevent or delay the onset of COPD.
**Correct Answer:** C.