Phenotypic variability and diffuse arterial lesions in a family with Loeys Dietz syndrome type 4

Clin Genet 2017: 91: 458 462 Printed in Singapore. All rights reserved Short Report 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd CLINICAL GENETICS doi: 10.1111/cge.12838 Phenotypic variability and diffuse arterial lesions in a family with Loeys Dietz syndrome type 4 Mazzella J.-M., Frank M., Collignon P., Langeois M., Legrand A., Jeunemaitre X., Albuisson J. Phenotypic variability and diffuse arterial lesions in a family with Loeys Dietz syndrome type 4. Clin Genet 2017: 91: 458 462. John Wiley & Sons A/S. Published by John Wiley & Sons Ltd, 2016 Syndromic thoracic aortic aneurysm and dissection (TAAD) can suggest Marfan, vascular Ehlers Danlos or Loeys Dietz (LDS) syndromes. Several of the TGFβ-pathway-related genes predispose to different types of LDS. Heterozygous loss-of-function variations in TGFβ2 have been shown to be responsible for a novel form of syndromic TAAD associated with an impairment of the mitral valve and cerebrovascular disease called Loeys Dietz syndrome type 4 (LDS4). We report the clinical characterization of a LDS4 French family with sudden deaths and diffuse vascular lesions, caused by a frameshift mutation in TGFβ2 gene: c.[995del]; p.(leu332trpfster27). Clinical characteristics include aneurysm of aortic sinus, skeletal and cutaneous features compatible with a syndromic form of TAAD (joint hypermobility, scoliosis, and easy bruises), intracranial aneurysms and rare mitral valve involvement. Iliac aneurysms, systemic medium caliber arteries dissections, and mild developmental delay were present in the family, and have not been described in LDS4. Phenotypic variability was also an important finding, including absence of clinical vascular events at advanced age in one case. Our data expand the phenotype of LDS4: we confirm that TGFβ2 mutations are responsible for true LDS syndrome with non-specific features of connective tissue disorders and diffuse vascular lesions. Adapted vascular follow up and prevention has to be proposed for these patients. Conflict of interest The authors declare no conflict of interests. J.-M. Mazzella a,m.frank a,p. Collignon b, M. Langeois c,a. Legrand a,d,e,x.jeunemaitre a,d,e and J. Albuisson a,d,e a Hôpital Européen Georges Pompidou, Centre de Référence des Maladies Vasculaires Rares, Hôpitaux de Paris, Paris, France, b Centre Hospitalier Intercommunal Toulon-La Seyne-sur-Mer, Service de Génétique Médicale, Toulon, France, c Centre de Référence National Syndromes de Marfan et apparentés, Hôpitaux de Paris, Hôpital Bichat-Claude-Bernard, Paris, France, d Sorbonne Paris Cité, Université Paris Descartes, Paris, France, and e Paris Cardiovascular Research Centre, INSERM, U970, Paris, France Key words: diffuse vascular lesions Loeys Dietz syndrome type 4 Phenotypic variability transforming-growth-factorβ (TGFβ) signaling pathway Corresponding author: Juliette Albuisson, Hôpital Européen Georges Pompidou, Centre de Référence des Maladies Vasculaires Rares, Assistance Publique-Hôpitaux de Paris, F-75015 Paris, France. Tel.: +33 1.56 09 54 87 Fax: +33156093884 e-mail: Juliette.albuisson@aphp.fr Received 23 March 2016, revised and accepted for publication 18 July 2016 Thoracic aortic aneurysms may lead to aortic dissection or rupture, causing premature death of young adults. The pathophysiology of thoracic aortic aneurysms and dissections is complex and both syndromic and non-syndromic forms of familial thoracic aortic aneurysm and dissection (TAAD) have been described (1). The main genes responsible for these syndromic forms are FBN1 (Marfan syndrome, MFS), TGFβR1/2 (Loeys Dietz syndrome, LDS1/2), SMAD3 (aneurysm osteoarthritis syndrome, AOS and LDS3), COL3A1 (vascular Ehlers Danlos syndrome, veds), ACTA2 (non-syndromic TAAD), MYH11 (TAAD with patent ductus arteriosus), MYLK (TAAD7) and SLC2A10 (arterial tortuosity syndrome, ATS) (2 13). Several of those syndromes highlight the implication of the transforming-growth-factorβ (TGFβ) signaling pathway in the aortic fragility (14, 15). In 2012, two different studies, led by Boileau et al. (16) and Lindsay et al. (17), identified TGFβ2 as another gene responsible for familial TAAD with additional 458

Expanding the phenotypic spectrum of LDS4 (a) (b) Fig. 1. Characterization of a new pathogenic variation in TGFβ2 in a large French pedigree. (a) Pedigree of family with TGFβ2 variation. Circles indicate females, squares indicate males. The proband (III-2) is indicated with a black arrow. Ages are besides symbols (y = years). The symbols filled in black denote individuals with cardiovascular features: ( ), aortic lesion such as TAAD or abdominal aortic dissection; ( ), lesion of medium caliber arteries; ( ), bicuspid aortic valve; ( ), cerebrovascular disease. Current age or age of death ( ) is indicated above each individual. Sudden death is represented by a gray dot ( ). Genetic status: (+), carrier patient; ( ), non-carrier patient. (b) Sanger sequencing result in the proband (III-2). Partial sequencing electropherogram of TGFB2 exon 6 obtained from proband blood leukocytes gdna. Upper and downer panels respectively correspond to forward (F) and reverse (R) sequences. The blue arrow shows heterozygous TGFβ2 deletion c.[995del] leading to a premature stop codon 27 codons downstream. clinical features overlapping MFS, LDS and veds. The corresponding disorder was classified as Loeys Dietz syndrome type 4 (LDS4, MIM#614816). Because of these recent findings, several cases have been reported, describing LDS4 as a late-onset TAAD (18) associated with mild clinical features (19), impairment of mitral valve (20) and cerebrovascular disease (16). Unlike other types of LDS, no implication of medium size arteries has been described yet. Here we report a large family of LDS4 presenting with skin and skeletal features, early TAAD, cerebrovascular disease and iliac artery aneurysms, expanding the spectrum of LDS4 to systemic medium caliber arteries. Family presentation The proband III-2 (Fig. 1a) was initially addressed to our French National Reference Centre for Rare Vascular Diseases (www.maladies-vasculaires-rares.fr) in 2008 at 37 years. He had a non-complicated rapid-growth aortic root aneurysm of the sinus of Valsalva, along with familial history of sudden deaths and vascular lesions. Besides, he had been treated for a congenital hip dislocation and had undergone bilateral inguinal hernia surgery in childhood (Table 1). He also had initial learning disabilities, which were resolved in adulthood. On the clinical exam, he had thin skin, easy bruises, joint hypermobility, scoliosis, pes planus and a Poland Syndrome (21). The patient had also dysmorphic features including hypertelorism, mild malar hypoplasia, discrete retrognatism, attached earlobes and reduction of the periorbitary fat (Fig. 2a). He underwent magnetic resonance angiography (MRA), computed tomography angiography (CTA) and Doppler Ultra Sound (DUS) measurement of heart and vasculature (aorta, supra-aortic trunks, digestive, renal and iliac arteries), 459

Mazzella et al. Table 1. Clinical features summary of TGFβ2 patients Clinical features Proband (III-2) Son (IV-2) Aunt (II-6) Aunt (II-8) Aunt (II-9) Cardiovascular Thoracic aortic aneurysm + + + Thoracic aortic dissection + + Abdominal aortic aneurysm + Aneurysm/dissection of medium caliber extracerebral arteries + NA + + + Systemic arterial tortuosity + NA + + + Cerebrovascular disease NA + Bicuspid aortic valve + + Mitral valve prolapse a a Skeletal Marfanoïd morphotype + + + + Arachnodactyly NA Joint hypermobility + + + + + Pectus deformity NA + NA Club-foot/Pes planus + + + Scoliosis + + + Congenital hip dislocation + NA NA Hammertoes + NA NA High-arched palate + Cutaneous Thin skin + + + NA Easy bruising + Enlarged scar NA + + + Hernia + NA + NA Varicose veins NA + NA Stria atrophicae NA + NA Other Bifid uvula NA Dural ectasia NA NA NA Perineal complication NA NA + +, present;, absent; NA, not analyzed;. a Grade 1 mitral valve regurgitation. revealing grade 1 mitral regurgitation, a bilateral iliac tortuosity and a right common iliac aneurysm (Fig. 2b). During the follow up, he underwent Bentall aortic root replacement at 43 years-old (at aortic diameter 54 mm). After informed consent, molecular testing was run by Sanger sequencing of several genes responsible of syndromic and non-syndromic TAAD (COL3A1, TGFβR2, ACTA2 and TGFβ2) on his blood sample. A heterozygous deletion c.[995del]; p.(leu332trpfster27) was found in TGFβ2 (Fig. 1b) a frameshift variant leading to a premature stop codon in exon 6. Family members were proposed clinical evaluation and targeted genetic screening. Five relatives were diagnosed also having molecularly proven LDS4 (Fig. 1 and Table 1). The proband s son (IV-2), aged of 9 years, had a bicuspid aortic valve (BAV) and an aneurysm of the sinus of Valsalava (30 mm, Z-score = 3.59 related to body surface area). He had thin skin, joint hypermobility, pes planus and hammer toes. He had also a medical and physical follow up for mild psychomotor delay: he started walking at the age of 2 and needed personal assistance during his schooling. His half-sister (IV-1), aged of 17 years, was asymptomatic but had not benefited yet of any cardiovascular investigation. She also had learning disabilities requiring personal assistance in childhood. Four aunts of the proband could be tested. Three of them were positive (II-6, II-8 and II-9) and had skeletal and cutaneous signs of LDS4, including joint hypermobility, tall stature, arachnodactyly and dolichostenomelia, enlarged scars, and cardiovascular features. Individual II-6 was examined at 60 years old. She had many evocative features such as scoliosis, pectus deformity, thin skin, surgically treated inguinal hernia, varicose veins and high-arched palate, but no history of vascular complications. However CTA and DUS revealed aortic and carotid artery tortuosity, grade-1 mitral regurgitation, a right internal carotid artery dissection and an asymptomatic bilateral common iliac aneurysm (Fig. 2c). At 26 years old, individual II-8 presented in immediate post-partum an aortic dissection eventually involving the entire aorta in a context of BAV, requiring Bentall procedure. A dilatation of the initial part of the brachiocephalic artery was observed during her follow up and a uterine artery rupture occurred at 49 years in a context of abdominal traumatism. At 54 years old, she had dilatation of the dissected aorta to 60 mm of size without associated atherosclerosis, which was treated by an aorto-bi-iliac bypass (Fig. 2d). II-9 had early obstetrical complications, with two successive ruptures of the recto-uterine pouch, requiring 460

Expanding the phenotypic spectrum of LDS4 Fig. 2. Clinical pictures and radiological features of the proband and some family members. (a) Pictures of the proband. Left panel: scoliosis, dolichostenomelia and Poland syndrome; upper panel: thumb hypermobility; lower panels: dysmorphic features such as hypertelorism, mild malar hypoplasia, discrete retrognatism and reduction of the periorbitary fat. (b) Vascular imaging of the proband (III-2). Left panel: three-dimensional computed tomography (CT) scan showing a voluminous aneurysm of the sinus of Valsalva (arrow); right panel: MRA showing the right common iliac aneurysm (arrow), with a diameter approximately twice as large as the contralateral artery. (c) Three-dimensional CT scan in II-6. Left panel: right carotid artery tortuosity (arrow); right panel: bilateral common iliac aneurysm (arrows). (d) Patient II-8. Left panel: CTA disclosing an acute type A aortic dissection spreading to supra-renal abdominal aorta (arrows); right panel: aortic tortuosity (arrows) observable on CT scan. (e). Cerebral CTA in II-9 showing a right middle cerebral artery aneurysm (arrow). an early hysterectomy at the age of 26 years. After 10 years, she suffered a stroke secondary to a ruptured aneurysm of the right middle cerebral artery, which was successfully treated by clipping during an elective surgery. MRA and CTA evaluation of medium caliber arteries revealed other silent arterial lesions: a right vertebral fusiform aneurysm, a right vertebral artery tortuosity and several intracranial aneurysms (Fig. 2e). In addition, the proband s mother (II-1) and grand-father (I-1) died suddenly, at the age of 30 and 49 years, respectively. An aunt (II-2) died of thoracic aortic rupture at 58 years old. Discussion LDS4 is a newly described autosomal dominant pathology, involving TAAD, several other cardiovascular features and cutaneous and skeletal signs. It is caused by mutations in the TGFβ2 gene. Through the analysis of a large French family, we expand the arterial phenotypic spectrum of LDS4 to medium size arteries, which is consistent with other types of LDS. The proband was initially evaluated by the French National Reference Centre for Rare Vascular Diseases for the first time in 2008, before LDS4 was described. He was then followed-up until description of the pathogenicity of TGFβ2 variants and heterozygous frameshift variant in the TGFβ2 gene was showed by the team who first reported the importance of this new gene (www.marfan.fr). In accordance with Leutermann et al. (18), we observed in this family clinical features that overlap with the veds spectrum such as lesions of medium caliber arteries, joint hypermobility, thin skin, easy bruises, evocative morphotype and perineal complications (Table 1 and Fig. 2). Other clinical features, such as TAAD, intracranial aneurysms and pectus deformity, could also suggest a syndrome within the MFS-LDS1/2 spectrum (Table 1). Many of these anomalies represent unspecific signs of extracellular matrix disorders, and the penetrance of vascular complications in the family was incomplete, two features that led to diagnosis difficulties. However, when present, the aortic lesions had severe consequences: (i) sudden death at 30 years caused by a thoracic aortic rupture (II-1); (ii) thoracic aortic dissection requiring emergency aortic root replacement at 24 years (II-8); (iii) sudden death at 49 years of unknown cause (I-1). Ritelli et al. (19) recently described an Italian LDS4 family without any vascular complication and a TGFβ2 splice-site with partial conservation of the corresponding transcript. That led them to conclude that LDS4 is at the mildest end of the LDS phenotypic spectrum. Our report is in contradiction with Ritelli et al. s observation and highlights the phenotypic heterogeneity of LDS4 as well as the severity of aortic lesions in some cases. One of the important characteristics of the disease in this family was the presence of lesions of medium or small caliber arteries. Each positive patient investigated (II-6, II-8, II-9, III-1, IV-2) had lesions such as aneurysms or dissections (Table 1). Arterial accidents occurred all along the arterial tree. To the best of our knowledge, this is the first study mentioning cardiovascular assessment of systemic medium caliber arteries in LDS4 patients. Cerebrovascular disease had been searched for in the same four patients as previously mentioned. Only II-8 (25%) had a middle cerebral artery rupture and many asymptomatic intracranial aneurysms, which is 461

Mazzella et al. in accordance with the observations of Boileau et al. (16). These data confirm that LDS4 patients must benefit intracranial arteries imaging. In their report, Renard et al. (20), found that four among six non-related LDS4 patients had mitral valve prolapse (MVP). None of the five affected patients in our family who benefited from cardiac echography had frank MVP. Only two of them were classified as grade 1 mitral regurgitation (III-1 and II-6). These discrepancies might be the consequence of a recruitment bias: Renard et al. mentioned that two LDS4 patient were recruited only because of the significant and severe MVP. Our observation further suggests the important intrafamilial and interfamilial phenotypic variability of expression of TGFβ2 variations. Although already described in LDS1/2 (22), developmental delay and learning disabilities might be new features of LDS4. Indeed, the proband and his two children (IV-1 and IV-2) probably shared mild psychomotor delay, for which other family members could not be assessed. However, this unspecific phenotype needs to be confirmed. We recommend seeking for past or present psychomotor delay in all LDS4 patients in order to properly characterize this feature. Our data expand the phenotype of LDS4, which seems more similar to other LDS than previously proposed. LDS4 should then be considered in either situation: patients of all ages with syndromic or non-syndromic TAAD with or without BAV, MVP, lesions of medium caliber arteries and cerebrovascular disease. Our description finally suggests that TGFβ2 should be part of any genetic screening strategy for rare aneurysmal and dissecting conditions. Acknowledgements We acknowledge the patients and their family, for their kind participation to this work. Ethical approval CE-HUPO (Ethics Committee of University Hospital West-Paris) approved this study. References 1. 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