Familial Thoracic Aortic Aneurysm Dissection

What is Familial Thoracic Aortic Aneurysm Dissection?

Familial thoracic aortic aneurysm and dissection (familial TAAD) involves problems the large blood vessel that distributes blood from the heart to the rest of the body, called the aorta. Familial TAAD affects the upper part of the aorta, near the heart. This part of the aorta is called the thoracic aorta because it is located in the chest (thorax). Other vessels that carry blood from the heart to the rest of the body (arteries) can also be affected by familial TAAD.

In familial TAAD, the aorta can become weakened and stretched (dilatation), which can lead to a bulge in the blood vessel wall (an aneurysm). Aortic dilatation may also lead to a sudden tearing of the layers in the aortic wall (aortic dissection), allowing blood to flow abnormally between the layers. These aortic abnormalities are potentially life-threatening because they can decrease blood flow to other parts of the body such as the brain or other vital organs, or cause the aorta to break open (rupture).

How does Familial Thoracic Aortic Aneurysm Dissection affect families?

Familial TAAD is inherited in an autosomal dominant pattern, which means one copy of an altered gene in each cell can be sufficient to cause the condition. In most cases, an affected person has one affected parent. However, some people who inherit an altered gene never develop the aortic abnormalities associated with the condition; this situation is known as reduced penetrance.

What are the symptoms?

Aortic aneurysms usually have no symptoms.

However, depending on the size, growth rate, and location of these abnormalities, they can cause:

• pain in the jaw, neck, chest, or back
• swelling in the arms, neck, or head
• difficult or painful swallowing
• hoarseness
• shortness of breath
• wheezing
• chronic cough
• coughing up blood
• severe, sudden chest or back pain
• unusually pale skin (pallor)
• faint pulse
• numbness or tingling (paresthesias) in one or more limbs
• paralysis

Some individuals in affected families show mild features of related conditions called Marfan syndrome or Loeys-Dietz syndrome. These features include:

• tall stature
• stretch marks on the skin
• unusually large range of joint movement (joint hypermobility)
• sunken or protruding chest

Occasionally, people with familial TAAD develop aneurysms in the brain or in the section of the aorta located in the abdomen (abdominal aorta).

Some people with familial TAAD have heart abnormalities that are present from birth (congenital). Affected individuals may also have a soft out-pouching in the lower abdomen (inguinal hernia), an abnormal curvature of the spine (scoliosis), or a purplish skin discoloration (livedo reticularis) caused by abnormalities in the tiny blood vessels of the skin (dermal capillaries). However, these conditions are also common in the general population. Depending on the genetic cause of familial TAAD in particular families, they may have an increased risk of developing blockages in smaller arteries, which can lead to heart attack and stroke.

What is the treatment for Familial Thoracic Aortic Aneurysm Dissection?

Familial TAAD is inherited in an autosomal dominant pattern, which means one copy of an altered gene in each cell can be sufficient to cause the condition. In most cases, an affected person has one affected parent. However, some people who inherit an altered gene never develop the aortic abnormalities associated with the condition; this situation is known as reduced penetrance.

Resources

Genetics Home Reference - www.ghr.nlm.nih.gov

The American Heart Association - www.heart.org