AJR:189, July 2007 W29 AJR 2007; 189:W29–W35 0361–803X/07/1891–W29 © American Roentgen Ray Society Johnson et al. MDCT Angiography of Loeys-Dietz Syndrome Vascular Imaging • Pictorial Essay Loeys-Dietz Syndrome: MDCT Angiography Findings Pamela T. Johnson 1 Jennifer K. Chen 2 Bart L. Loeys 3 Harry C. Dietz 3,4 Elliot K. Fishman 1 Johnson PT, Chen JK, Loeys BL, Dietz HC, Fishman EK Keywords: aorta, cardiovascular disease, CT angiography, genetics, head and neck imaging, Loeys-Dietz syndrome DOI:10.2214/AJR.06.1316 Received October 5, 2006; accepted after revision January 17, 2007. 1 Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, 601 N Caroline St., Rm. 3251, Baltimore, MD 21287. Address correspondence to P. T. Johnson ([email protected]). 2 Johns Hopkins University School of Medicine, Baltimore, MD. 3 McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD. 4 Howard Hughes Medical Institute, Chevy Chase, MD. WEB This is a Web exclusive article. OBJECTIVE. Loeys-Dietz syndrome is a newly described phenotype caused by heterozy- gous mutations in the genes encoding type I or II transforming growth factor-β (TGF-β) recep- tor. Characterized by a unique constellation of clinical and pathologic findings, Loeys-Dietz syndrome manifests with aggressive vascular pathology. Aneurysms may form at a young age and have a propensity for arterial dissection. In addition, aneurysms rupture at diameters smaller than those used to dictate surgical intervention for other syndromes and disorders. This article presents the spectrum of arterial pathology that may be identified on MDCT angiogra- phy in patients with Loeys-Dietz syndrome. CONCLUSION. For patients with Loeys-Dietz syndrome, early diagnosis and rapid in- tervention are instrumental in averting catastrophic events. Serial imaging assessment by radi- ologists is an important component in the management of these patients. n 2005, Loeys et al. [1], Dietz, and others described a new syndrome caused by heterozygous muta- tions in the genes encoding type I or II transforming growth factor-β (TGF-β) receptor. They identified a number of families with similar multisystem abnormalities, in whom an increase in TGF-β signaling results in phenotypes closely resembling Marfan syndrome, Marfanoid craniosynostosis syn- drome (Shprintzen-Goldberg syndrome), and vascular Ehlers-Danlos syndrome [1, 2]. However, Loeys-Dietz syndrome is charac- terized by a unique constellation of clinical and pathologic manifestations [1, 2]. Since the original report, two subtypes of Loeys-Dietz syndrome have been delineated [2]. Loeys-Dietz syndrome type I patients have both craniofacial and vascular disorders. The most characteristic craniofacial findings are hypertelorism and broad or bifid uvula or cleft palate, two of the three components of the clin- ical triad that also includes arterial aneurysms and tortuosity [2]. In contradistinction, Loeys- Dietz syndrome type II patients may have a bifid uvula but do not have a cleft palate, cranio- synostosis, or hypertelorism [2]. Surgical in- tervention is needed and death occurs at a later age in Loeys-Dietz syndrome type II than in Loeys-Dietz syndrome type I patients [2]. In fact, the cardiovascular outcome of Loeys- Dietz syndrome can be predicted by a “cranio- facial severity index” [2] that is based on pres- ence of cleft palate and craniosynostosis, the degree of increased intraocular distance, and the uvular configuration [2]. Additional manifestations of Loeys-Dietz syndrome include blue sclera, malar hypopla- sia, exotropia, and retrognathia [1]. Cervical spine instability, pectus deformity, arachno- dactyly, craniosynostosis, scoliosis, and joint laxity are some of the many musculoskeletal manifestations [1, 2]. The pronounced tortu- osity of the arteries (Fig. 1) in Loeys-Dietz syndrome is a finding not frequently identi- fied in the general population [2]. Aneurysms have been identified throughout the arterial system, with an increased propensity for rup- ture or dissection [1, 2]. In addition, Loeys- Dietz syndrome patients may be afflicted with congenital cardiac anomalies [1, 2]. Cardiovascular Manifestations of Loeys-Dietz Syndrome Versus Marfan Syndrome and Vascular Ehlers-Danlos Syndrome Features that distinguish Loeys-Dietz syn- drome from Marfan syndrome have been elu- cidated [1]. Some phenotypic manifestations are common to both syndromes, whereas other physical examination findings are unique to one or the other [1, 3, 4]. Marfan syndrome re- sults from mutations in the FBN1 gene, and aortic root dilatation is the leading cause of I Downloaded from www.ajronline.org by 171.243.67.90 on 05/23/23 from IP address 171.243.67.90. Copyright ARRS. For personal use only; all rights reserved
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