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Pulmonary arterial hypertension (PAH) is a rare condition that causes high blood pressure in the arteries of the lungs. In many cases, the cause is unknown — this is called idiopathic PAH (iPAH). However, for some people, PAH is linked to inherited genetic mutations (changes).
When PAH is diagnosed in two or more members of the same family, it’s known as familial pulmonary arterial hypertension (FPAH) or heritable pulmonary arterial hypertension (HPAH).
If PAH runs in your family, it’s important to let your healthcare provider know. They can help assess your risk and guide the next steps, which may include genetic counseling or screening.
The most common cause of FPAH is a mutation in a gene called bone morphogenetic protein receptor 2 (BMPR2). Gene mutations can be passed down through families and are linked to many diseases, including FPAH.
About 80 percent of people with FPAH have a BMPR2 mutation. This gene change can also be found, though less often, in people with iPAH and congenital heart disease. Other less common genetic causes of FPAH include mutations in the TBX4, CAV1, ACVRL1, and ALK1 genes.
People usually inherit one copy of each gene from each biological parent. If just one copy of the BMPR2 gene is mutated, a person may be at risk for developing PAH.
However, FPAH shows what’s called incomplete penetrance, meaning that not everyone who inherits the gene mutation will develop the condition. In fact, only 20 percent who inherit a mutated BMPR2 gene will go on to develop PAH.
If you’re diagnosed with PAH, your doctor might recommend genetic testing to check for gene mutations that could be causing the disease. If a genetic mutation linked to FPAH is found, close family members should also consider getting tested. If no mutation is found, testing family members may not be necessary.
Even without symptoms, family members who carry a known FPAH-related gene mutation should have annual medical evaluations to monitor their health. Yearly checkups are also advised for family members with a family history of FPAH but whose genetic status is still unknown.
Because learning about gene mutations can bring up big questions and concerns, genetic counseling is strongly recommended before and after testing. A genetic counselor can help you and your family understand what your results mean and guide the next steps.
Symptoms of FPAH are the same as in other forms of PAH. The most common symptoms include:
Consult your primary care doctor or a cardiology specialist right away if you notice persistent symptoms of PAH. If you think you may have a family history of PAH, more testing may be recommended for your family members even if they don’t have any symptoms.
To explore a diagnosis of PAH, a healthcare provider will start by reviewing your symptoms and medical history. They may also ask whether anyone in your family has had PAH.
Doctors use several tests to confirm a diagnosis of PAH. If they suspect a heritable form, they might recommend genomic sequencing — a test that reads your DNA in detail. This can help identify changes in genes such as BMPR2, which are linked to FPAH.
Although having a genetic change doesn’t always mean you’ll develop PAH, a family history of the condition can offer important clues. If a known gene mutation is found, that may help confirm whether your PAH is heritable.
Getting the types of tests described below may be important to figuring out your diagnosis. Cardiopulmonary exercise testing (CPET) and cardiac MRI are other tests that doctors may use to help with diagnosis or to better understand how a person is affected by PAH.
Routine laboratory tests will measure blood cell counts and the amount of antibodies in your blood — special proteins that help your body fight off infection. Lab tests can also detect other risk factors for pulmonary hypertension, including HIV infection, blood-clotting disorders, and autoimmune disease (when your body’s defense system mistakenly attacks healthy cells).
One of the main tests required for diagnosing PAH is an echocardiogram. An echocardiogram uses sound waves to make pictures of your heart. Doctors use it to check if your heart is larger than it should be, which could mean potential heart problems. An echocardiogram can also estimate pulmonary arterial pressure and determine if there is any strain on the heart.
Although pulmonary arterial pressure can be estimated with an echocardiogram, it’s more accurately measured by right heart catheterization. This minimally invasive procedure involves a catheter (thin tube) being inserted into the heart and pulmonary arteries.
Right heart catheterization measures the pressure in the pulmonary arteries and the level of oxygen in the blood. It can also identify ventricular dysfunction — when the heart ventricles don’t work properly — caused by PAH.
Treatments for FPAH are similar to those used in other forms of PAH. Most therapies focus on:
Some medications promote vasodilation (widening blood vessels) to improve circulation. Others target different pathways involved in the disease. Many people with PAH benefit from combination therapy, which uses two or more treatments to improve outcomes.
Prostacyclin is a substance your body makes to help blood vessels widen and blood flow more easily. Prostacyclin analogs mimic this effect and are often prescribed to treat PAH. These medications may be used alone or combined with other therapies.
Soluble guanylate cyclase (sGC) stimulators help relax blood vessels by boosting the activity of a protein called guanylate cyclase. These medications are sometimes used to treat a specific form of pulmonary hypertension called chronic thromboembolic pulmonary hypertension (CTEPH). In CTEPH, old blood clots block blood flow in the lungs.
Endothelins are molecules that make blood vessels constrict (tighten). Endothelin receptor antagonists (ERAs) block this effect, helping blood vessels stay open and easing pressure in the lungs. ERAs are often combined with other treatments, such as prostacyclin analogs or phosphodiesterase type 5 (PDE5) inhibitors.
Phosphodiesterase type 5 is like a switch in your body that can tighten blood vessels, just like endothelins do. But PDE5 inhibitors work to open up those blood vessels instead. This helps to lower blood pressure and improve blood flow throughout the body.
PDE5 inhibitors are sometimes combined with endothelin receptor antagonists for more effective blood pressure control. In some people with high-risk PAH, PDE5 inhibitors may also be used in combination with prostacyclin analogs.
Activin is a type of protein that helps control how cells grow and develop — including the cells that line your blood vessels. In PAH, a faulty activin signaling pathway can lead to the growth of smooth muscle cells inside lung arteries. This extra cell growth can narrow the arteries and make it harder for blood to flow.
Activin signaling inhibitors target this pathway to help keep blood vessels healthier and reduce disease progression.
Anticoagulants — also called blood thinners — help prevent blood cells from sticking together and forming clots. In people with PAH, this may help reduce the risk of complications such as heart attacks, strokes, or blocked arteries in the lungs.
Also called water pills, diuretics help the body get rid of excess fluid and sodium through urination. This can ease swelling and reduce the amount of work the heart has to do, thereby lowering pulmonary blood pressure.
Calcium channel blockers help blood vessels relax and widen, making it easier for the heart to pump blood through the lungs. These medications may also reduce blood pressure and relieve heart strain.
While there is no cure for FPAH, early treatment can help slow disease progression and improve quality of life. Without treatment, the prognosis (outlook) for PAH is generally poor — but outcomes are better when the condition is diagnosed early and treated promptly.
Your doctor will perform regular risk assessments to help monitor disease progression and how well your body responds to treatments.
If a known or suspected genetic cause for PAH runs in your family, genetic counseling is generally recommended to understand your risk of developing PAH. Talking to a genetic counselor will help you understand the process of genetic testing and decide whether it’s the right option for you. This can help identify the problem early so that you can start treatment quickly and improve your long-term outlook.
Talk With Others Who Understand
On myPHteam, the social network for people with pulmonary hypertension and their loved ones, more than 56,000 members come together to ask questions, give advice, and share their stories with others who understand life with pulmonary hypertension.
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A myPHteam Member
I was diagnosed a little over a year ago I do not like the oxygen either but I need it I am 68 I also have fibrosis please try to keep ;positive u need a pulse ox to keep track of your sats
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