LOEY-DIETZ SYNDROME

 

Loeys-Dietz syndrome is a genetic disorder of the connective tissue — cells that support or connect different structures in the body. Loeys-Dietz syndrome affects bones, blood vessels, skin, heart and other organs. Common signs include wide-set eyes, aortic or arterial aneurysm or dissection and a variety of skeletal, skin and digestive features.
Loeys-Dietz Syndrome: What You Need to Know
• Diagnosis involves an echocardiogram, consideration of a wide range of physical features and genetic testing.
• Different people have different combinations of symptoms.
• Because the syndrome was just identified in 2005, many doctors may not be aware of its existence. Speak to a genetic counsellor if your doctor suspects Loeys-Dietz syndrome.
• Goals of treatment are to reduce stress on the aorta and arteries, reduce bone and muscle complications and pain, and treat digestive and allergic issues. In some cases surgery may be necessary.
Although Loeys-Dietz syndrome shares features with other connective-tissue disorders such as Marfan, Shprintzen-Goldberg and Ehlers-Danlos syndromes, it stems from different genetic mutations. The conditions are also managed differently.

What is 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 provide 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.
How is Loeys-Dietz Syndrome different from Marfan Syndrome?
In the past, many individuals with Loeys-Dietz syndrome were mistakenly 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 surgery is considered 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). Therefore surgery is recommended when the aorta approaches 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, surgery is recommended when an aortic root enlargement is progressive and the valve is above 1.8-2.0cm. Aortic valves of this measurement can typically handle an adult sized graft, therefore repeat surgery should not be necessary.
Is aortic root replacement surgery a necessary treatment?
The goal of aortic root replacement surgery is to replace weak tissue before a tear occurs. 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 Loeys-Dietz Syndrome do extremely well with vascular surgery, as tissue is not particularly friable or difficult to sew.
What is the long-term management for Loeys-Dietz Syndrome?
Individuals with Loeys-Dietz syndrome should remain 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. 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 percent of individuals with Loeys-Dietz syndrome have cervical spine instability and should be assessed for with flexion-extension x-rays of the cervical spine.
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 the presence or 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. Decongestants and other stimulants should also be avoided.

Diagnosing Loeys-Dietz Syndrome – Dr Bart Loeys
Summary of the diagnostic symptoms of Loeys-Dietz Syndrome by Dr Bart Loeys from University of Antwerp Hospital, who first described the condition in 2005 with his colleague, Dr Hal Dietz.

Sarah Bowdin – Loeys-Dietz Syndrome Foundation Conference 2014
Dr. Sarah Bowdin a Medical Advisory Committee member of the Loeys-Dietz Syndrome Foundation and Geneticist from The Hospital for Sick Children in Toronto, presents an overview connective tissue disorders and Loeys-Dietz syndrome.

Differences in manifestations of Marfan Syndrome, Ehlers-Danlos Syndrome and Loeys-Dietz Syndrome
Dr Loeys, co-founder of the main gene responsible for Loeys-Dietz syndrome, presents a comparative discussion of the pathogenetic basis and clinical manifestations of these three related connective tissue disorders