SNP Shot: Genomic Insights

Pulmonary arterial hypertension (PAH) is a condition that gradually worsens, defined by high blood pressure (hypertension) in the pulmonary artery. This artery transports blood from the heart to the lungs. PAH is a specific type of pulmonary hypertension, a broader category of conditions. Pulmonary hypertension develops when many small arteries in the lungs become narrower, increasing resistance to blood flow. The heart must then work harder to pump blood through the lungs, leading to increased pressure in the pulmonary artery and the right ventricle (the heart chamber that pumps blood to the lungs). Over time, this increased pressure can damage the right ventricle.

The signs and symptoms of PAH become noticeable when the elevated blood pressure can no longer compensate for the increased resistance in the lungs. This results in a reduced flow of oxygenated blood from the lungs to the body. The most common symptoms are shortness of breath (dyspnea) during physical activity and fainting. As the condition progresses, other symptoms may appear, including dizziness, swelling (edema) in the ankles or legs, chest pain, and a rapid heartbeat.

Inheritance:

PAH is usually sporadic, meaning it occurs in people without a family history of the condition. These cases are called idiopathic pulmonary arterial hypertension. Around 20% of these idiopathic cases are linked to mutations in genes known to be associated with PAH, but often the specific causative gene mutation is unknown. Familial pulmonary arterial hypertension refers to inherited cases of the condition. When inherited, it typically follows an autosomal dominant pattern. This means that only one copy of a mutated gene in each cell is enough to cause the disorder. However, many individuals with a mutated gene may not develop PAH; this is known as reduced penetrance.