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Loeys-Dietz Syndrome

  • "Your child's care team may include physicians from several disciplines, all of whom have experience treating children with the various symptoms of Loeys-Dietz syndrome."

    –Joan M. Stoler, MD, Boston Children's clinical geneticist

    When your child has a rare medical condition, it can be especially challenging. Parents often have a harder time finding accurate information about the symptoms your child might be suffering from, as well as what medical treatments are available.

    If your child has been diagnosed with Loeys-Dietz syndrome, you probably have a number of questions. At Boston Children’s Hospital, we have the answers you’re looking for.

    Here’s what you need to know about Loeys-Dietz syndrome and how it can affect your child:

    • Loeys-Dietz syndrome is a relatively rare congenital (present at birth) condition that affects the formation of your child’s connective tissue.
    • The main concerns for children with Loeys-Dietz syndrome are the development of aneurysms of the arteries, such as of the aorta, which result in weakening of the affected blood vessel. They can be fatal if they’re not treated.
      • Because there’s no cure for Loeys-Dietz syndrome, doctors focus on monitoring the development of these aneurysms, treating them medically and if necessary, surgically repairing the aneurysm, as well as managing your child’s other symptoms in order to allow your child to lead a healthy life.

    How Boston Children’s Hospital approaches Loeys-Dietz syndrome

    At Boston Children’s we focus on the whole child, not just his condition—that’s one reason we are frequently ranked as a top pediatric hospital in the United States.

    We specialize in innovative, family-centered care. From your first visit, you’ll work with a team of professionals who are committed to supporting all of your family’s physical and psychosocial needs.

    • While there’s no cure for Loeys-Dietz syndrome, we have many methods of managing your child’s symptoms—and helping your child have a happy childhood and go on to live a healthy, productive life.

    Our multidisciplinary team

    Loeys-Dietz syndrome is a complex condition, and no one specialist is equipped to treat your child for all his symptoms.

    • That’s why at Boston Children’s, we have an innovative multidisciplinary approach to treating children with Loeys-Dietz syndrome.

    Your child’s care team may include physicians from several disciplines, such as genetics, ophthalmology, orthopedics, plastic surgery, general surgery and cardiology who have experience in treating kids with the varied symptoms of Loeys-Dietz syndrome.

    We’re also continually involved in research with physicians and researchers in other institutions in an attempt to provide the most up-to-date and effective care for children with Loeys-Dietz syndrome.

    Marfan syndrome. Loeys-Dietz syndrome. What’s the difference?

    Loeys-Dietz syndrome is very similar to Marfan syndrome. In fact, until recently Loeys-Dietz was called “Marfan syndrome type 2.” However, there are some differences in both the symptoms your child might have, as well as the way in which we treat them.

    Here’s an especially helpful page put together by the National Marfan Foundation. Near the bottom of the page, there’s a link to a publication that details the differences between Marfan syndrome and Loeys-Dietz syndrome.

    What makes Boston Children’s different

    We’re known for our science-driven approach — we’re home to the most extensive research enterprise located in a pediatric hospital in the world, and we partner with a number of top biotech and health care organizations—but our physicians never forget that your child is a child, and not just a patient.

    Loeys-Dietz syndrome: Reviewed by Joan M. Stoler, MD
    © Boston Children's Hospital; posted in 2011

    Boston Children's Hospital

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  • While the word “syndrome” can be a frightening one, it simply refers to a group of symptoms that occur together.

    • When a doctor says that your child has Loeys-Dietz syndrome, he means that your child has some or all of the symptoms associated with the condition.
      • Some children who have Loeys-Dietz syndrome have all the symptoms that we discuss below, while others only have one or two.

    For more information about the causes and symptoms of Loeys-Dietz syndrome, as well as what they mean for your child, read on.

    How common is it?

    Loeys-Dietz syndrome is a fairly rare genetic condition.

    • Until recently, Loeys-Dietz syndrome was called Marfan syndrome type 2. Only a small percentage of the one in 5,000 to 10,000 children who have Marfan syndrome have this variety.

    When does it appear?

    Loeys-Dietz syndrome is present at birth but, because it can resemble other conditions, it may not be diagnosed immediately.

    • If your child has any of the characteristic facial features [LINK to Signs and Symptoms section] of Loeys-Dietz syndrome, your pediatrician may notice them and recommend further testing.
    • Other children with the syndrome are diagnosed when they come in for evaluation of skeletal or cardiac problems, such as a heart murmur or other medical condition.

    Who gets Loeys-Dietz syndrome?

    It’s equally common in boys and girls.

    Why is Loeys-Dietz syndrome a problem?

    Kids with Loeys-Dietz syndrome have abnormal connective tissue, which can lead to problems in many different parts of the body. Here are some of the major problems a child with Loeys-Dietz syndrome can have:

    • Arterial aneurysms are the main concerns for children with Loeys-Dietz syndrome. The condition causes aneurysms (or bulges) in the vessel wall, which then becomes weakened and can burst, leading to a life-threatening emergency. This can involve the aorta (the major artery arising from the heart) or other blood vessels, such as those in the brain.
      • If your child has been diagnosed with Loeys-Dietz syndrome, it’s essential that he be monitored continually by a doctor, because these aneurysms tend to rupture at a young age — and at a size smaller than seen in children with Marfan syndrome.
    • Your child may have a variety of gastrointestinal problems, such as difficulty absorbing food and chronic diarrhea, abdominal pain, and gastrointestinal bleeding and inflammation. Children with Loeys-Dietz syndrome are also more likely to have food allergies than unaffected children.
    • Another complication can be instability in the vertebrae directly below the skull (cervical vertebrae). A small number of children with Loeys-Dietz syndrome need surgery to prevent slippage of the bones around their spinal cord. They can have other skeletal problems such as loose joints, scoliosis (curvature of the spine) and chest wall deformities (depression or protrusion of the breast bone).

    When should we see a doctor?

    As part of your child’s ongoing care, your doctor should regularly monitor your child for aneurysms. See the Treatment & Care section for more information.

    • If your child has been diagnosed with Loeys-Dietz syndrome and seems to be having intense or prolonged pain—anywhere in his body—he might be experiencing the dissection of an aneurysm. You should go to the emergency room immediately.


    What causes Loeys-Dietz syndrome?

    Loeys-Dietz syndrome is a genetic disorder caused by a mutation (gene change) in one of the genes in charge of the formation of connective tissue that connects and supports other tissues like skin, muscle and bones. It’s sometimes referred to as the “glue” that holds the body together.

    How is Loeys-Dietz syndrome inherited?

    Loeys-Dietz syndrome is an autosomal dominant condition, which means that a child need only have one abnormal copy of the responsible gene to have the condition. (Each of us has two copies of each gene, with the exception of genes on the X chromosome in boys.) In about 25 percent of cases, an affected child has inherited a copy of the abnormal gene from an affected parent. In the other 75 percent, the change in the gene has arisen anew in the affected child.

    If the parent is found to have the abnormal gene, there is a 50 percent chance that the next child will also have it. If neither parent has the abnormal gene and is unaffected, then the risk to other children is low.

    • If you have Loeys-Dietz syndrome yourself and want to have children, consider discussing your family plans with a genetic counselor who can help you understand the implications of the syndrome for your children.

    Signs and symptoms

    What signs and symptoms might my child have?

    Loeys-Dietz syndrome affects different kids in different ways. Not all children have all the signs and symptoms listed below. Your child’s pediatrician will be best able to determine whether your child should be evaluated by a geneticist for Loeys-Dietz syndrome.

    Here are some of the more common signs and symptoms of Loeys-Dietz syndrome, organized by the part of your child’s body they affect:;

    Heart and blood vessels

    • twisting or spiraled arteries
    • dilated (or enlarged) arteries—can lead to life-threatening aneurysms if they rupture
    • congenital heart defects like atrial septal defect


    • long fingers and toes
    • clubfoot
    • scoliosis (curvature of the spine)    
    • loose joints that are abnormally flexible
    • pectus excavatum—sometimes called “funnel chest” or “sunken chest”
    • pectus carinatum—sometimes called “pigeon breast”


    • hypertelorism—widely spaced eyes
    • blue sclerae—blue tinge to the whites of the eyes


    • easy bruising and scarring
    • skin that feels especially soft and is translucent in places

    Head and face

    • craniosynostosis — premature closing of the sutures in the skull, which can lead to increased skull pressure and facial abnormalities
    • small or receding chin
    • flat cheek bones
    • split uvula (the tissue that hangs down in the back of the throat is divided)
    • cleft palate

    What’s an aneurysm?

    An aneurysm is a bulge in the wall of a blood vessel. It’s a problem because the wall is weakened where it is stretched (picture a balloon that’s been overinflated); if the blood pressure becomes too high, the aneurysm can rupture, creating a life-threatening emergency.

    Questions to ask your doctor

    You and your family are key players in your child’s medical care. It’s important that you share your observations and ideas with your child’s health care provider and that you understand your provider’s recommendations.

    If your child has been diagnosed with Loeys-Dietz syndrome and you’ve set up an appointment, you probably already have some ideas and questions on your mind. But at the appointment, it can be easy to forget the questions you wanted to ask. It’s often helpful to jot them down ahead of time so that you can leave the appointment feeling like you have the information you need.

     Some of the questions you may want to ask include:

    • What kinds of tests will our child need?
    • What can we do at home to help manage our child's symptoms?
    • What symptoms should we be on the lookout for?
    • What kinds of treatments will our child need?
    • Where can we go for further information? Printed materials? Online resources?

    Coping and support

    We understand that you may have a lot of questions when your child is diagnosed with Loeys-Dietz syndrome. How will it affect my child long term? What can we do to treat the symptoms? Will any of the symptoms get better without treatment? We’ve provided some answers to those questions in the following pages, but there are also a number of other resources to help you and your family through this difficult time.

    • Boston Children’s Center for Familiesis dedicated to helping families locate the information and resources they need to better understand their child’s particular condition and take part in their care. All patients, families and health professionals are welcome to use the Center’s services at no extra cost. The center is open Monday through Friday from 8 a.m. to 7 p.m., and on Saturdays from 9 a.m. to 1 p.m. Please call 617-355-6279 for more information.
    • The Boston Children’s chaplaincy is a source of spiritual support for parents and family members. Our program includes nearly a dozen clergy members—representing Episcopal, Jewish, Lutheran, Muslim, Roman Catholic, Unitarian and United Church of Christ traditions—who will listen to you, pray with you and help you observe your own faith practices during your child’s treatment.
    • Boston Children’s Behavioral Medicine Clinic helps children who are being treated on an outpatient basis at the hospital — as well as their families — understand and cope with their feelings about:
      • being sick
      • facing uncomfortable procedures
      • handling pain
      • taking medication
      • preparing for surgery
      • changes in friendships and family relationships
      • managing school while dealing with an illness
      • grief and loss
    • Boston Children’s Pediatric Psychiatry Consultation Service is made up of expert and compassionate pediatric psychologists, psychiatrists, social workers and other mental health professionals who understand the unique circumstances of hospitalized children and their families. The service works with children who have been admitted to the hospital—and their family members—and operates on a referral basis.
    • The Experience Journal was designed by Boston Children’s psychiatrist-in-chief David DeMaso, MDand members of his team. This online collection features thoughts, reflections and advice from kids and caregivers about their medical experiences.
    • getting to Boston Children’s
    • accommodations
    • navigating the hospital experience
    • resources that are available for your family
  • Diagnosing Loeys-Dietz syndrome can be challenging because sometimes, a child’s symptoms are mild or even non-existent. Even among members of the same family, the signs and symptoms of Loeys-Dietz syndrome vary widely — both in their features and in their severity. Your child’s pediatrician will be best able to determine whether your child should be evaluated by a geneticist for Loeys-Dietz syndrome.

    At Boston Children’s Hospital, we can help you identify whether your child has Loeys-Dietz syndrome — and begin treatment to manage your child’s specific symptoms.

    How is Loeys-Dietz syndrome diagnosed?

    During your initial visit, a doctor will take a detailed family medical history and perform a comprehensive physical exam on your child. The combination of these evaluations will usually provide enough information for the doctor to suspect a diagnosis of Loeys-Dietz syndrome.

    • The next step is an echocardiogram (an ultrasound of your child’s heart), which allows doctors to check for enlargement of the aorta or other heart defects. At this point, a cardiologist will be brought in to help assess your child.
    • Depending on the evaluation, your doctor may also suggest more imaging studies (such as an MRI or a CT scan) to look for aneurysms in other arteries.
    • Finally, if your medical team believes that your child has Loeys-Dietz syndrome, a geneticist can test for mutations by taking a small sample of blood. If a gene mutation is found in your child, the doctor will often recommend parental testing as well to get a more complete genetic picture.
  • Undoubtedly, you were distressed when you learned that your child has Loeys-Dietz syndrome. That's understandable — no parent wants her child to be unwell, and Loeys-Dietz syndrome can cause some serious health problems.

    However, keep in mind that the symptoms — and their severity — of Loeys-Dietz syndrome vary widely. And although there is no cure for Loeys-Dietz syndrome, advances in treatment mean that doctors can help increase your child's life expectancy and quality of life.

    At Boston Children's Hospital, a team of medical specialists will work with you and your child to design an individualized plan of treatment — so that we may effectively manage the condition and allow your child to have a healthy, productive life.

    Our multidisciplinary team

    Loeys-Dietz syndrome is a complex condition, and no one specialist is equipped to treat your child for all of his symptoms. That's why at Children's, we have an innovative multidisciplinary approach to treating children with Loeys-Dietz syndrome.

    Your child's care team may include physicians from several disciplines, such as Ophthalmology, Orthopedics, Genetics and Cardiology who have experience treating kids with the varied symptoms of Loeys-Dietz Syndrome.

    We're also continually involved in research with physicians and researchers in other institutions in an attempt to provide the most up-to-date and effective care for children with Loeys-Dietz syndrome.

    How is Loeys-Dietz syndrome treated?

    Loeys-Dietz syndrome can be a complicated condition, and it affects different children in different ways.

    Some children with Loeys-Dietz syndrome may only need minimal treatment. For those children who do need more treatment, we focus on managing your child's symptoms.

    So what kinds of treatments are there?

    They fall into several categories, depending on what part of your child's body is affected.   

    Cardiovascular system

    Since the most dangerous complication of Loeys-Dietz syndrome is the rupture of an aneurysm, such as of the aorta — which is potentially fatal — it's important to get the right treatment.

    • Typically, we treat aneurysms with medications called beta blockers that slow down your child's heart rate and lower the blood pressure in your child's arteries to reduce the risk of rupture.
    • Your doctor will also want to continually monitor your child's aorta and arteries for aneurysms; depending on the size of the aneurysms and their rates of growth, your doctor may recommend an imaging scan every six months to a year.
    • Your doctor will likely suggest that your child avoid certain high-impact activities such as competitive contact sports and weightlifting because they can place higher stress on the aorta and increase the chances of a life-threatening rupture.

    A good rule of thumb for cardiovascular activity is that your child should be able to hold a conversation while exercising.


    • x-ray to check for instability in your child's cervical vertebrae (the vertebrae at the top of the spine). In rare instances, if the connection is very unstable, surgery may be recommended.
    • Some children with Loeys-Dietz syndrome suffer from craniosynostosis, a condition that causes the sutures in the skull to close too early, resulting in increased pressure within the skull and a distortion of the facial bones. For more information on treatment, see our craniosynostosispage.
    • Your child may need surgery or bracing to help control scoliosis. For more information on those techniques, see our scoliosis page.
    • If your child has clubfoot there are several methods of treatment that have been proven effective. For more information, see our clubfoot page.
    • Some children with Loeys-Dietz syndrome have congenital hip dislocation. For more information on this condition and how we treat it, see our page on hip dysplasia
    • Chest wall abnormalities can be corrected surgically or with braces. For more information, see our pages on pectus carinatum (pigeon breast) and pectus excavatum (funnel chest).

    Joints and bones

    • If your child has the flexible joints characteristic of Loeys-Dietz syndrome, he may experience some pain after physical activity. The orthopedic physician will discuss ways to manage this pain.

    Facial features and mouth

    • If your child was born with a cleft palate (a hole in the roof of his mouth), surgeons can repair it, typically when he is around nine months of age. Visit our cleft palatepage for more information.
    • Hypertelorism (widely spaced eyes) is not usually an issue that needs any intervention.

    What kind of support will we get?

    At Boston Children's, we consider you and your child integral parts of the care team and not simply recipients of care. Your care team will be with you every step of the way to ensure that you and your child are getting the support you need.

    Supportive care

    We want to maximize the safety and effectiveness of whatever therapy you and your child's doctor decide upon.

    • Supportive care involves preventing and treating infections and side effects of treatment to keep your child as comfortable as possible while we're working to manage the symptoms of her Loeys-Dietz syndrome.     

    Continual follow-up care

    Your child's physician and other members of your care team will work with you to set up a schedule of follow-up visits.

  • At Boston Children's Hospital, our care is informed by our research, and our discoveries in the laboratory strengthen the care we provide at each child's bedside. Children’s scientific research program is one of the largest and most active of any pediatric hospital in the world. In particular, our efforts are focused on:

    New treatments for heart wall defects

    Pedro del Nido, MD, chief of Cardiac Surgery, and his colleagues are developing surgical instruments to enable beating heart surgical repair of the atrial septal defects common in children born with Loeys-Dietz syndrome. These specialized devices will allow minimally invasive repairs inside the beating heart that are not currently possible.

    Clinical trials that could provide clues about strengthening the aorta

    In a 2006 study, the blood pressure medication losartan completely prevented aortic aneurysms in mice with Marfan syndrome. Ron Lacro, MD, director of Boston Children's Cardiovascular Genetics Clinic, managed a clinical trial to assess the effectiveness of losartan on children and young adults with Marfan syndrome. This study also holds great promise for children with Loeys-Dietz who also suffer from this weakening of the aorta. Read more about the study.

    We’re also continually involved in research with physicians and researchers in other institutions in an attempt to provide the most up-to-date and effective care for children with Loeys-Dietz syndrome.

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