Loeys-Dietz syndrome is a genetic disorder that affects the connective tissues of the affected individual. It was recently discovered as a disorder of its own in 2005 by geneticists Dr. Harry Dietz and Dr. Bart Loeys. Up until then, it was lumped together with another, similar disorder known as Marfan syndrome.
Loeys-Dietz syndrome is most commonly characterized by the occurrence or increased risk of aortic aneurysms. Aneurysms occur when the tissues of the aorta form outpouchings that may potentially burst. In patients with Loeys-Dietz syndrome, the outpouchings will burst even when they are quite small due to the weakened and stretched tissues of the aorta. Other defining characteristics include arterial tortousity (spiraled or twisted arteries most commonly found in the neck), wide-spaced eyes, a broad or split uvula (the hanging piece in the back of the mouth), early fusion of the skull bones, long fingers and toes, scoliosis of the spine, skin that has a soft texture or is translucent, and other congenital heart defects. Patients who have Loeys-Dietz syndrome may have some or none of the visible physical characteristics as this disorder is unique to each individual.
Patients who are diagnosed with Loeys-Dietz syndrome have a mutation of either the TGF-beta receptor l (TGFBR1) or TGF-beta receptor 2 (TGFBR2) gene. The TGFBR genes are responsible for signalling cellular movement, growth, and even cell death. The mutation of the TGFBR genes prevents normal signalling. This mutation is a dominant trait and only one mutant copy is needed to inherit the disorder.
Diagnosis of Loeys-Dietz syndrome is performed by both screening for the presence of aortic aneurysms and genetic testing for the mutant gene. The presence of aneurysms in the aorta is discovered by injecting a dye that is visible through X-rays. After the dye is injected, the patient’s aorta and other arteries will be viewed with the use of an X-ray, CT scan or MRI. Because aortic aneurysms can also be present in patients with other disorders, a genetic test that screens for the presence of the mutant TGFBR1 or TGFBR2 genes will also need to be performed.
Treatment for Loeys-Dietz syndrome includes surgical repair of the aortic aneurysm and frequent follow-up examinations using imaging techniques to view the aorta and other arteries that may develop aneurysms. Patients are also advised to avoid contact and competitive sports, isometric exercise, and frequent use of decongestants to keep from further straining the aorta. Exercise such as hiking, biking, swimming, tennis and jogging are allowable as long as the patient does not push themselves to the point of exhaustion.
Children who may have Loeys-Dietz syndrome but are undiagnosed are at the greatest risk of dying from a bursting aneurysm that goes undetected. Because this disorder is passed down through families carrying the dominant mutant gene, children should be screened as soon as possible even if they do not have any of the visible physical characteristics.
While there is no cure for Loeys-Dietz syndrome, it is still possible for patients with the disorder to live comfortably as long as their health is managed with regular doctor visits for aorta and arterial screenings.
