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Rossetti A, Spatjens RLH, Kammerer S, Stoks J, Firneburg R, Seyen SR, Helderman-Van Den Enden ATJM, Wilde AAM, Loeys BL, Saenen J, Heijman J, Volders PGA. An emerging role for DPP6: reciprocal regulation of INa-Ito and implications for arrhythmogenesis. Eur Heart J 2022. [DOI: 10.1093/eurheartj/ehac544.2886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background
Since the association of a chromosomal risk haplotype harboring dipeptidyl peptidase-like protein-6 (DPP6) to familial idiopathic ventricular fibrillation (iVF), a growing number of DPP6 missense variants has been reported in patients with ventricular tachyarrhythmias. The mechanisms underlying DPP6 mediated-arrhythmogenesis are not yet fully elucidated. DPP6 is a subunit of the transient outward potassium (Ito) channel complex in Purkinje cells (PC) and ventricular myocytes (VM).
Purpose
Since other Ito-channel subunits (Navβ1, KChIP2, KCNE4 and DPP10) are also known to antagonize INa, we examined whether DPP6 could play a broader role in the inter-regulation of Kv4.3 and Nav1.5 channels. We identified two novel DPP6 variants (p.Arg274His and p.His213Tyr), each segregating in families with QT/QU prolongation. DPP6 p.Arg274His carriers suffered from iVF, ectopic beats from the conduction system, and mitral valve prolapse. Other DPP6 variants (p.Ala751Val identified in this study; p.Gln526His and DPP6-T p.His332Arg published) are associated with Brugada syndrome (BrS). We hypothesized that DPP6 has opposing effects on INa and Ito displaying a reciprocal regulation of these currents.
Methods and results
First, we determined the effect of the DPP6 variants on INa and Ito in transfected CHO cells. Ito density was significantly reduced only when PC subunits were co-expressed with the DPP6 p.Arg274His or p.His213Tyr variants. Indeed, DPP6 modulates Nav1.5 channels in CHO cells by reducing INa Peak and INa Late, whereas DPP6 mutants p.Arg274His or p.His213Tyr resulted in an increase of both components compared to WT. Co-immunoprecipitation experiments in human endocardium confirmed an interaction between DPP6 and Nav1.5 channels. Computing of mutant DPP6-driven Ito-INa changes in a published human PC model led to significant prolongation of the action potential duration, mainly caused by increased INa Late.
On the other hand, the DPP6 p.Gln526His and p.Ala751Val variants, linked to BrS, led to a decreased INa Peak compared to the WT, while there was a tendency towards increased Ito density in both PC and VM molecular setups.
DPP6 (p.Arg274His and p.Ala751Val) transfection experiments in hiPSC cardiomyocytes, expressing endogenous INa and Ito, confirmed the reciprocal results obtained in CHO cells.
Conclusions
DPP6 regulates INa and Ito in a reciprocal manner. The cardiac phenotype of DPP6 variants could encompass a spectrum between two opposite poles: 1) QT/QU prolongation by DPP6 variants causing loss of Ito and gain of INa, like p.Arg274His and p.His213Tyr versus 2) BrS by DPP6 variants leading to gain of Ito and loss of INa, like p.Gln526His and p.Ala751Val.
Funding Acknowledgement
Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): ESC Personal research grant, obtained in 2019
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Affiliation(s)
- A Rossetti
- Cardiovascular Research Institute Maastricht (CARIM) , Maastricht , The Netherlands
| | - R L H Spatjens
- Cardiovascular Research Institute Maastricht (CARIM) , Maastricht , The Netherlands
| | - S Kammerer
- Dresden University of Technology , Dresden , Germany
| | - J Stoks
- Cardiovascular Research Institute Maastricht (CARIM) , Maastricht , The Netherlands
| | - R Firneburg
- Dresden University of Technology , Dresden , Germany
| | - S R Seyen
- Cardiovascular Research Institute Maastricht (CARIM) , Maastricht , The Netherlands
| | | | | | - B L Loeys
- University Hospital Antwerp , Antwerp , Belgium
| | - J Saenen
- University Hospital Antwerp , Antwerp , Belgium
| | - J Heijman
- Cardiovascular Research Institute Maastricht (CARIM) , Maastricht , The Netherlands
| | - P G A Volders
- Cardiovascular Research Institute Maastricht (CARIM) , Maastricht , The Netherlands
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Loeys BL, Gerber EE, Riegert-Johnson D, Iqbal S, Whiteman P, McConnell V, Chillakuri CR, Macaya D, Coucke PJ, De Paepe A, Judge DP, Wigley F, Davis EC, Mardon HJ, Handford P, Keene DR, Sakai LY, Dietz HC. Mutations in fibrillin-1 cause congenital scleroderma: stiff skin syndrome. Sci Transl Med 2010; 2:23ra20. [PMID: 20375004 PMCID: PMC2953713 DOI: 10.1126/scitranslmed.3000488] [Citation(s) in RCA: 156] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The predisposition for scleroderma, defined as fibrosis and hardening of the skin, is poorly understood. We report that stiff skin syndrome (SSS), an autosomal dominant congenital form of scleroderma, is caused by mutations in the sole Arg-Gly-Asp sequence-encoding domain of fibrillin-1 that mediates integrin binding. Ordered polymers of fibrillin-1 (termed microfibrils) initiate elastic fiber assembly and bind to and regulate the activation of the profibrotic cytokine transforming growth factor-beta (TGFbeta). Altered cell-matrix interactions in SSS accompany excessive microfibrillar deposition, impaired elastogenesis, and increased TGFbeta concentration and signaling in the dermis. The observation of similar findings in systemic sclerosis, a more common acquired form of scleroderma, suggests broad pathogenic relevance.
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Affiliation(s)
- B L Loeys
- Institute of Genetic Medicine and Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Broadway Research Building, Room 539, 733 North Broadway, Baltimore, MD 21205, USA
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Abstract
BACKGROUND AND PURPOSE Loeys-Dietz syndrome (LDS) is a recently described entity that has the triad of arterial tortuosity and aneurysms, hypertelorism, and bifid uvula or cleft palate. Its neuroradiologic manifestations have not been well delineated. We sought to describe the neuroradiologic features of LDS and to assess the manifestations that would warrant follow-up imaging. MATERIALS AND METHODS Two neuroradiologists retrospectively reviewed CT angiography (CTA), MR imaging, and plain film studies related to the head and neck in 25 patients ranging from 1 to 55 years of age, all of whom had positive genetic testing and clinical characteristics of LDS. Arterial tortuosity was evaluated by subjective assessment of 2D and 3D volumetric CTA and MR angiography data. Craniosynostosis and spinal manifestations were assessed by using plain films and CT images. MR images mostly of the head were reviewed for associated findings such as hydrocephalus, Chiari malformation, etc. Clinical manifestations were collated from the electronic patient record. RESULTS All patients had extreme arterial tortuosity, which is characteristic of this syndrome. Thirteen patients had scoliosis, 12 had craniosynostosis, 8 had intracranial aneurysms, 6 had spinal instability, 3 had dissections of the carotid and vertebrobasilar arteries, 3 had hydrocephalus, 4 had dural ectasia, 2 had a Chiari malformation, and 1 had intracranial hemorrhage as a complication of vascular dissection. CONCLUSIONS Significant neuroradiologic manifestations are associated with LDS, predominantly arterial tortuosity. Most of the patients in this series were young and, therefore, may require serial CTA monitoring for development of intra- and extracranial dissections and aneurysms, on the basis of the fact that most of the patients with pseudoaneurysms and dissection were older at the time of imaging. Other findings of LDS such as craniosynostosis, Chiari malformation, and spinal instability may also need to be addressed.
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Affiliation(s)
- V J Rodrigues
- Department of Radiology, Johns Hopkins Medical Institutions, 600 N Wolfe Street, Baltimore, MD 21287, USA
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Faivre L, Collod-Beroud G, Callewaert B, Child A, Binquet C, Gautier E, Loeys BL, Arbustini E, Mayer K, Arslan-Kirchner M, Stheneur C, Kiotsekoglou A, Comeglio P, Marziliano N, Wolf JE, Bouchot O, Khau-Van-Kien P, Beroud C, Claustres M, Bonithon-Kopp C, Robinson PN, Adès L, De Backer J, Coucke P, Francke U, De Paepe A, Jondeau G, Boileau C. Clinical and mutation-type analysis from an international series of 198 probands with a pathogenic FBN1 exons 24-32 mutation. Eur J Hum Genet 2008; 17:491-501. [PMID: 19002209 DOI: 10.1038/ejhg.2008.207] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Mutations in the FBN1 gene cause Marfan syndrome (MFS) and a wide range of overlapping phenotypes. The severe end of the spectrum is represented by neonatal MFS, the vast majority of probands carrying a mutation within exons 24-32. We previously showed that a mutation in exons 24-32 is predictive of a severe cardiovascular phenotype even in non-neonatal cases, and that mutations leading to premature truncation codons are under-represented in this region. To describe patients carrying a mutation in this so-called 'neonatal' region, we studied the clinical and molecular characteristics of 198 probands with a mutation in exons 24-32 from a series of 1013 probands with a FBN1 mutation (20%). When comparing patients with mutations leading to a premature termination codon (PTC) within exons 24-32 to patients with an in-frame mutation within the same region, a significantly higher probability of developing ectopia lentis and mitral insufficiency were found in the second group. Patients with a PTC within exons 24-32 rarely displayed a neonatal or severe MFS presentation. We also found a higher probability of neonatal presentations associated with exon 25 mutations, as well as a higher probability of cardiovascular manifestations. A high phenotypic heterogeneity could be described for recurrent mutations, ranging from neonatal to classical MFS phenotype. In conclusion, even if the exons 24-32 location appears as a major cause of the severity of the phenotype in patients with a mutation in this region, other factors such as the type of mutation or modifier genes might also be relevant.
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Affiliation(s)
- L Faivre
- Centre de Génétique, CHU, Dijon, France.
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Faivre L, Collod-Beroud G, Child A, Callewaert B, Loeys BL, Binquet C, Gautier E, Arbustini E, Mayer K, Arslan-Kirchner M, Stheneur C, Kiotsekoglou A, Comeglio P, Marziliano N, Halliday D, Beroud C, Bonithon-Kopp C, Claustres M, Plauchu H, Robinson PN, Adès L, De Backer J, Coucke P, Francke U, De Paepe A, Boileau C, Jondeau G. Contribution of molecular analyses in diagnosing Marfan syndrome and type I fibrillinopathies: an international study of 1009 probands. J Med Genet 2008; 45:384-90. [PMID: 18310266 DOI: 10.1136/jmg.2007.056382] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND The diagnosis of Marfan syndrome (MFS) is usually initially based on clinical criteria according to the number of major and minor systems affected following international nosology. The number of FBN1 mutation carriers, at risk of aortic complications who would not be properly diagnosed based only on clinical grounds, is of growing importance owing to the increased availability of molecular screening. The aim of the study was to identify patients who should be considered for FBN1 mutation screening. METHODS Our international series included 1009 probands with a known FBN1 mutation. Patients were classified as either fulfilling or not fulfilling "clinical" criteria. In patients with unfulfilled "clinical" criteria, we evaluated the percentage of additional patients who became positive for international criteria when the FBN1 mutation was considered. The aortic risk was evaluated and compared in patients fulfilling or not fulfilling the "clinical" international criteria. RESULTS Diagnosis of MFS was possible on clinical grounds in 79% of the adults, whereas 90% fulfilled the international criteria when including the FBN1 mutation. Corresponding figures for children were 56% and 85%, respectively. Aortic dilatation occurred later in adults with unfulfilled "clinical criteria" when compared to the Marfan syndrome group (44% vs 73% at 40 years, p<0.001), but the lifelong risk for ascending aortic dissection or surgery was not significantly different in both groups. CONCLUSIONS Because of its implications for aortic follow-up, FBN1 molecular analysis is recommended in newly suspected MFS when two systems are involved with at least one major system affected. This is of utmost importance in patients without aortic dilatation and in children.
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Faivre L, Collod-Beroud G, Loeys BL, Child A, Binquet C, Gautier E, Callewaert B, Arbustini E, Mayer K, Arslan-Kirchner M, Kiotsekoglou A, Comeglio P, Marziliano N, Dietz HC, Halliday D, Beroud C, Bonithon-Kopp C, Claustres M, Muti C, Plauchu H, Robinson PN, Adès LC, Biggin A, Benetts B, Brett M, Holman KJ, De Backer J, Coucke P, Francke U, De Paepe A, Jondeau G, Boileau C. Effect of mutation type and location on clinical outcome in 1,013 probands with Marfan syndrome or related phenotypes and FBN1 mutations: an international study. Am J Hum Genet 2007; 81:454-66. [PMID: 17701892 PMCID: PMC1950837 DOI: 10.1086/520125] [Citation(s) in RCA: 371] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Accepted: 05/16/2007] [Indexed: 11/04/2022] Open
Abstract
Mutations in the fibrillin-1 (FBN1) gene cause Marfan syndrome (MFS) and have been associated with a wide range of overlapping phenotypes. Clinical care is complicated by variable age at onset and the wide range of severity of aortic features. The factors that modulate phenotypical severity, both among and within families, remain to be determined. The availability of international FBN1 mutation Universal Mutation Database (UMD-FBN1) has allowed us to perform the largest collaborative study ever reported, to investigate the correlation between the FBN1 genotype and the nature and severity of the clinical phenotype. A range of qualitative and quantitative clinical parameters (skeletal, cardiovascular, ophthalmologic, skin, pulmonary, and dural) was compared for different classes of mutation (types and locations) in 1,013 probands with a pathogenic FBN1 mutation. A higher probability of ectopia lentis was found for patients with a missense mutation substituting or producing a cysteine, when compared with other missense mutations. Patients with an FBN1 premature termination codon had a more severe skeletal and skin phenotype than did patients with an inframe mutation. Mutations in exons 24-32 were associated with a more severe and complete phenotype, including younger age at diagnosis of type I fibrillinopathy and higher probability of developing ectopia lentis, ascending aortic dilatation, aortic surgery, mitral valve abnormalities, scoliosis, and shorter survival; the majority of these results were replicated even when cases of neonatal MFS were excluded. These correlations, found between different mutation types and clinical manifestations, might be explained by different underlying genetic mechanisms (dominant negative versus haploinsufficiency) and by consideration of the two main physiological functions of fibrillin-1 (structural versus mediator of TGF beta signalling). Exon 24-32 mutations define a high-risk group for cardiac manifestations associated with severe prognosis at all ages.
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Affiliation(s)
- L Faivre
- Centre de Génétique, Centre Hospitalier Universitaire, Dijon, France.
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Abstract
The Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder with a prevalence of 2-3 per 10,000 individuals and symptoms ranging from skeletal overgrowth, cutaneous striae to ectopia lentis and aortic dilatation leading to dissection. Mutation in the gene for fibrillin-1 (FBN1) cause MFS and other related disorders of connective tissue, grouped as fibrillinopathies. Fibrillin-1 is the main constituent of extracellular microfibrils. Microfibrils can exist as individual structures or associate with elastin to form elastic fibers. This article provides an overview of the current diagnostic criteria and medical management, estimates the role of fibrillin-1 mutation analysis, sheds new light on genotype-phenotype correlations and summarizes new insights on the pathogenesis of this disorder based on mouse models.
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Abstract
UNLABELLED We report on a patient who presented at 5 years of age with a hemiparesis due to a middle cerebral artery infarction. An embolism had originated from a mycotic aneurysm located in the internal carotid artery. For several months prior to admission he had been suffering from therapeutically resistant candidiasis of the mouth and nails. Family history revealed chronic mycotic infections of the skin, hair, nails and mouth in the father and paternal grandmother suggestive of chronic mucocutaneous candidiasis with autosomal dominant mode of inheritance. Clipping of the aneurysm, after 3 months of anti-mycotic treatment, followed by sustained treatment with itraconazole and fluconazole, led to a favourable outcome. CONCLUSION Chronic mucocutaneous candidiasis can be associated with an intracranial aneurysm and complicated by cerebral infarction.
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Affiliation(s)
- B L Loeys
- Department of Paediatrics, Ghent University School of Medicine, Belgium
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Loeys BL, Lemmerling MM, Van Mol CE, Leroy JG. The Meier-Gorlin syndrome, or ear-patella-short stature syndrome, in sibs. Am J Med Genet 1999; 84:61-7. [PMID: 10213048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
The Meier-Gorlin syndrome, first described by Meier and Rothschild [1959: Helv Paediatr Acta 14:213-216] and further delineated by Gorlin et al. [1975: A Selected Miscellany, p 39-50], is characterized by short stature, slender body build, craniofacial anomalies, microtia, delayed skeletal development, hypogonadism, and absence of the patellae. It has also been called the ear-patella-short stature syndrome [Boles et al., 1994: Clin Dysmorphol 3:207-214]. We report on two brothers with Meier-Gorlin syndrome, the younger of whom was more severely affected. Both patients had severe deafness and congenital labyrinthine anomalies, which have not previously been described as features of this syndrome. The neuromotor and mental development of these patients was adversely affected by late diagnosis, deafness, and their sociocultural environment, but their cognitive ability fell within the range observed in other Meier-Gorlin patients. Neuroradiographic imaging and functional inner ear investigations are recommended in the diagnostic workup of this rather specific, probably autosomal recessive mental retardation syndrome with multiple congenital anomalies.
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Affiliation(s)
- B L Loeys
- Department of Pediatrics, Ghent University, School of Medicine, Belgium
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