What is Loeys-Dietz syndrome?
Loeys-Dietz syndrome is a disorder due to a defective cellular receptor, either transforming growth factor ß–receptor 1 or 2 (TGFBR 1 or 2). TGFBR 1 and 2 are cell receptors that receive important signals that direct cell growth, specialization, movement, and cell death. Defects in the receptors mean that the cells do not get the important signals that they need to grow properly, so the involved tissues do not function normally. Manifestations of Loeys-Dietz can include, but are not limited to, the following:
- Heart and major blood vessels
- Skeletal system
Loeys-Dietz syndrome has only recently been described, and therefore it is uncertain how often it occurs. It appears to occur in equal numbers in males and females, and also appears equally in all races and ethnic groups.
What causes Loeys-Dietz syndrome?
Loeys-Dietz syndrome is caused by an abnormality (or mutation) in either one of two specific genes (TGFBR1 or TGFBR2). The mutated gene can occur spontaneously, or it can be passed along in families.
Loeys-Dietz syndrome is an autosomal dominant disorder. This means that each offspring of an affected parent will have a 50% chance of also being born with the disorder. Similarly, when a child is born with Loeys-Dietz syndrome to unaffected parents, the child will have a 50% risk of passing the gene on to the next generation.
Why is Loeys-Dietz syndrome a concern?
Children with Loeys-Dietz syndrome are at risk for serious problems involving the cardiovascular system, including the following:
- Arterial aneurysms. Weakening of the layers of the wall of the arteries, which leads to an increase in size. As the artery enlarges, the layers of the wall can separate (dissection), or tear completely through (rupture). Either of these conditions are life-threatening medical emergencies.
- Aortic aneurysms. Aneurysms of the aorta are common in Loeys-Dietz syndrome. The aorta is the large artery that carries blood out of the heart.
- Other arterial aneurysms. Aneurysms may occur in other arteries, such as those in the head and neck. Aneurysms in these areas can result in strokes.
- Arterial tortuosity. The arteries may become twisted, often looking like a corkscrew, which can compromise the arterial wall function.
What are the symptoms of Loeys-Dietz syndrome?
Abnormal function of transforming growth factor ß–receptors creates the abnormalities in organs and body structures that may be seen with Loeys-Dietz syndrome. A large number of of abnormalities can occur with the disorder and are listed below. Each child may experience symptoms differently. Symptoms may include:
Heart and blood vessels
- Enlargement of the aorta
- Tortuous arteries
- Tears in the aorta (aortic dissection)
- Bicuspid aortic valve
- Deformities of the breastbone
- Scoliosis, which is a sideways curvature of the spine, or kyphosis, which is a round curvature of the spine that can give the appearance of a hunchback
- Joint contractures
- Unusual arm span
- Long fingers and toes
- Translucent skin
- Easy bruising
The symptoms of Loeys-Dietz syndrome may resemble other problems or medical conditions. Always consult your child's health care provider for a diagnosis.
How is Loeys-Dietz syndrome diagnosed?
In addition to a complete medical history and physical examination, your child's health care provider may complete a family medical history to look for other family members with known Loeys-Dietz syndrome or some of the characteristics of the disease.
Other diagnostic tests for Loey-Dietz syndrome may include the following:
- Electrocardiogram (ECG or EKG). A test that records the electrical activity of the heart, shows abnormal rhythms (arrhythmias or dysrhythmias), and detects heart muscle damage.
- Echocardiography (echo). A procedure that evaluates the structure and function of the heart by using sound waves recorded on an electronic sensor that produce a moving picture of the heart and heart valves.
- Magnetic Resonance Imaging (MRI). A procedure that evaluates the structure of the arteries of the body using high-powered magnets to produce pictures of the vessels, as well as the heart.
- X-ray. A diagnostic test that uses invisible X-ray beams to produce images of internal tissues, bones, and organs onto film.
- DNA studies. A blood sample sent to the genetics lab can analyze the TGFBR1 & 2 genes to determine whether a mutation is present.
Because enlargement of the aorta, or some of the other findings may become more obvious over time, in order to be diagnosed with Loeys-Dietz syndrome, DNA studies must show an abnormalitiy.
Treatment for Loeys-Dietz syndrome
Currently, the only treatment that has been shown to improve life-expectancy in patients with Loeys-Dietz syndrome is surgery to repair aortic aneurysms before they tear.
Drug studies are currently ongoing to determine if medication therapy clearly demonstrates improvement in aneurysms. In the meantime, certain medications are typically used to keep the blood pressure at a good level.
At the present time, there is no cure for the disorder. Treatment is based on which organ systems are affected and managing the problems that arise. Recommendations for managing Loeys-Dietz syndrome may include the following:
- MRI to evaluate arterial aneurysms and tortuosity every 6 months
- An annual echocardiogram, or echo (to monitor the heart and aorta)
- Surgery to replace the aorta if the size is 4.2 cm or greater
- Monitoring of the skeletal system for abnormalities (such as scoliosis) that can be noted in childhood or adolescence
- Lifestyle adjustments (to reduce the risk of injury to the aorta, such as avoiding contact sports or stressful exercise)
Genetic counseling is important for people who have Loeys-Dietz syndrome and are planning to have a family. If one parent has the disorder, there is a 50 percent chance, with each pregnancy, for a child to also have Loeys-Dietz syndrome. In addition, women with Loeys-Dietz syndrome who become pregnant have significant risks for their health during pregnancy, due to the added stress that a pregnancy puts on the heart and aorta. Women with Loeys-Dietz syndrome should consult with their health care providers before pregnancy to determine if pregnancy is safe for them.
Long-term outlook for a child with Loeys-Dietz syndrome
Blood vessel problems pose the largest threat to a person with Loeys-Dietz syndrome, which emphasizes the importance of regular evaluation by your child's health care provider. Consult your child's health care provider for more information regarding the specific outlook for your child.
Because Loeys-Dietz syndrome is a newly recognized disorder, long-term survival information is not available. However, with advances in the diagnosis, evaluation, and management of the arterial abnormalities associated with Loeys-Dietz syndrome, the life expectancy for a person with the disease has increased in the last decade. Ongoing research will provide more accurate estimates of life expectancy.
For women with Loeys-Dietz syndrome, pregnancy and childbirth pose significant risks. These women should be evaluated with echocardiography and MRI prior to becoming pregnant. Cesarean delivery (C-section) is generally recommended for pregnant women with Loeys-Dietz syndrome to prevent strain on the aorta and decrease the risk of aortic dissection during labor.
Online Medical Reviewer:
Last Review Date: 01/01/0001