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Loeys-Dietz Syndrome

Loeys-Dietz syndrome is a connective tissue disorder that was first described in 2005. Most individuals with this disorder have craniofacial features that include hypertelorism (widely spaced eyes) and a bifid or broad uvula. In a smaller percentage of individuals, craniosynostosis (premature fusion of the skull bones), cleft palate and/or club foot are noted.  Almost 100% of patients show some type of abnormal skin findings including translucent skin, soft or velvety skin, easy bleeding, easy bruising, recurrent hernias, and scarring problems.

On radiological imaging, many individuals show tortuous vessels, especially in the neck vessels.  In the Loeys-Dietz syndrome, tortuous vessels are not “bad vessels” or vessels predisposed to aneurysm/tear, but they give us a diagnostic clue to suspect the diagnosis.

Most significantly in Loeys-Dietz syndrome, aneurysms throughout the arterial tree have been described.  The most common location of enlargement is the aortic root. 

 In the past, many individuals with Loeys-Dietz syndrome have previously been diagnosed with Marfan syndrome.  It is important to distinguish between Marfan syndrome and Loeys-Dietz syndrome because there are a few management differences. First, individuals with Loeys-Dietz syndrome are not at risk of having lens dislocation. Surgical management of aortic root enlargement is also different.  Typically in Marfan syndrome we consider moving forward with surgery when the aorta is around 5 cm; however, in Loeys-Dietz syndrome it has been recognized that individuals with aortic root measurements of 4 cm have shown aortic root dissection (in teens/adults), thus we counsel families to consider moving forward with cardiac surgery when their aortas are approaching this dimension. Valve-sparing aortic root replacement is a typically safe and well tolerated procedure in individuals with Loeys-Dietz syndrome. In children with more craniofacial involvement, we typically recommend moving forward with surgery in the presence of an aortic root enlargement that is progressive and the valve is above 1.8-2.0cm. Aortic valves of this measurement can typically handle an adult sized graft, thus we would not think repeat surgery will be necessary.

 The goal of aortic root replacement surgery is to replace weak tissue before a tear occurs. In our experience, individuals who experience tears (dissections) may be more predisposed to have further elongation of the tear or tears in branch vessels as secondary problems.  Individuals with LDS do extremely well with vascular surgery, as tissue is not particularly friable or difficult to sew.

Historically, Loeys-Dietz syndrome was first described/discovered because of its overlap with Marfan syndrome. In Marfan syndrome, it is believed that the mechanism behind the aortic root aneurysms is caused by excess TGF beta activity.  Mouse models of Marfan syndrome have shown that the aneurysms as well as lung, muscle and other heart valve issues can be attributed to excess TGF beta activity.  When these mouse models were given a TGF beta antagonist medication (), this stabilized aortic growth. Losartan is an FDA approved blood pressure medication that also antagonizes TGF beta activity.  Currently there are mouse models of Loeys-Dietz syndrome being produced and experiments to look at the impact of losartan on their vasculature are underway.  The effects of losartan on these mouse models will give us more information about possible benefits in individuals with Loeys-Dietz syndrome. However, when weighing the pros and cons of instituting losartan, because it does have low side effects and because of the potential benefit of stabilizing/preventing future aneurysm growth, many families with Loeys-Dietz syndrome are choosing to move forward  with Losartan as their medication of choice for blood pressure management.  This decision should be made in conjunction with your medical professionals.

 Individuals with Loeys-Dietz syndrome should remain cardiovascularly active with activities such as hiking, biking, swimming, tennis, jogging, and other activities.  A good rule is that you should be able to have conversation while you are playing these activities. We do advise that competitive and contact sports, isometric exercises, and exercises performed to the point of exhaustion should be avoided.  This includes push ups, sit ups, and pull ups.

 Approximately 15% of individuals with Loeys-Dietz syndrome have cervical spine instability and should be assessed for with flexion-extension x-rays of the cervical spine.

At this time, management of individuals with Loeys-Dietz syndrome includes  6 month to yearly echocardiograms and yearly head to pelvis CTA/MRA imaging to assess for aortic root  and heart valve function  as well as presence/progression of aneurysms found elsewhere in the arterial tree.  If MRAs continue to remain stable, the timing can possibly be more spaced out. Patients should follow guidelines described in their individualized plan and assessment.
Approximately 1/4-1/3 of individuals with Loeys-Dietz syndrome can also have gastrointestinal complications and severe food allergies.  

Orthopedic care for clubfoot, flat feet, scoliosis, c-spine instability, pectus anomalies, joint hypermobility should be investigated as needed.

 In general, some precautions regarding migraine and headache treatment (which is common in connective tissue disorders) includes avoidance of Imitrex, which works as a vasoconstrictor.   We recommended avoiding decongestants as they are stimulants as well.

The Loeys-Dietz Syndrome Foundation is an excellent resource for new information about LDS and family support. Their website is   More information can also be found at GeneReviews.


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