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Laghi A, Mandel VD, Zubba I, Franceschini C, Demofonte I, Chello C, Miraglia E, Ardigò M, Giustini S. Comprehensive analysis of pseudoxanthoma elasticum: epidemiological, genetic, and clinical findings from the leading Italian center. Ital J Dermatol Venerol 2024; 159:430-435. [PMID: 39069841 DOI: 10.23736/s2784-8671.24.07949-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
BACKGROUND Pseudoxanthoma elasticum (PXE) is a rare genetic autosomal recessive metabolic disease characterized by progressive mineralization and fragmentation of elastic fibers from soft connective tissues. The objective of our study was to analyze the epidemiological, genetic, cutaneous, and extracutaneous clinical data from the largest Italian monocentric cohort of PXE patients. METHODS We included all patients diagnosed with PXE and referred to Neurocutaneous Rare Diseases at Umberto I Polyclinic Hospital (Rome, Italy) between January 1983 and February 2024. A retrospective analysis of their data was performed. RESULTS We enrolled 86 patients (77.9% women), revealing compound heterozygosity in 19.8% of cases and homozygosity in 5.8%. Missense (34.9%), non-sense (5.8%), splice-site (5.8%), deletion (4.7%), and frameshift (2.3%) mutations were disclosed. Cutaneous alterations were noted in the neck (69.7%), axilla (33.7%), inguinal (17.5%), and cubital folds (11.7%). The most common ocular findings were angioid streaks (64.0%) and choroidal neovascularization (18.6%), with blindness reported in 5.8% of cases. Thicker intima-media was observed around the mid-fifties in the supra-aortic trunks (40.7%), lower limb arteries (32.6%), and renal arteries (4.7%). Regurgitation was more common in atrioventricular valves (48.8%) than in semilunar ones (10.5% and 9.3%). Dyslipidemia (19.8%), hypertension (18.8%), and fatty liver disease (12.8%) were prevalent, with calcifications found in the kidneys (25.6%), liver (15.1%), spleen (11.6%), and testicles (8.1% of males). Autoimmune diseases and depression were observed in 11.6% and 4.7% of cases, respectively. CONCLUSIONS Enhanced understanding of PXE can improve patients' quality of life and facilitate the development of more effective therapeutic strategies.
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Affiliation(s)
- Alessandro Laghi
- Unit of Dermatology and STDs, Department of Medicine, Celio Military Hospital, Rome, Italy -
- Unit of Dermatology, Department of Internal Medicine and Medical Specialties, Sapienza University, Rome, Italy -
| | - Victor D Mandel
- Unit of Porphyria and Rare Diseases, IRCCS San Gallicano Dermatological Institute, Rome, Italy
| | - Ilaria Zubba
- Unit of Dermatology, Department of Internal Medicine and Medical Specialties, Sapienza University, Rome, Italy
| | - Chiara Franceschini
- Unit of Porphyria and Rare Diseases, IRCCS San Gallicano Dermatological Institute, Rome, Italy
| | - Ilaria Demofonte
- Unit of Dermatology, Department of Internal Medicine and Medical Specialties, Sapienza University, Rome, Italy
| | - Camilla Chello
- Unit of Dermatology, Department of Internal Medicine and Medical Specialties, Sapienza University, Rome, Italy
| | - Emanuele Miraglia
- Department of Dermatology, San Sebastiano Hospital, Frascati, Rome, Italy
| | - Marco Ardigò
- Unit of Porphyria and Rare Diseases, IRCCS San Gallicano Dermatological Institute, Rome, Italy
- Unit of Dermatology, IRCCS Humanitas Clinic, Rozzano, Milan, Italy
| | - Sandra Giustini
- Unit of Dermatology, Department of Internal Medicine and Medical Specialties, Sapienza University, Rome, Italy
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Stumpf MJ, Winkler T, Siebigteroth M, Lenzen A, Weinhold L, Nickenig G, Hendig D, Skowasch D, Schahab N, Schaefer CA. Influence of pseudoxanthoma elasticum on the lipid profile and prognostic implications. VASA 2024. [PMID: 39017644 DOI: 10.1024/0301-1526/a001134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2024]
Abstract
Background: Pseudoxanthoma elasticum (PXE) is a rare, inherited disease characterised by specific skin lesions, progressive loss of vision and early onset atherosclerosis. Atherosclerosis in PXE leads to an increased rate of vascular occlusion and severe intermittent claudication. Although genetically determined, the individual course of PXE is highly variable. Up to now, there is no sufficient parameter to identify individuals at risk of rapid disease progression. This present study focused the lipid profile of patients with PXE and its possible influence on the clinical severity of peripheral artery disease (PAD). Patients and methods: 112 patients with PXE were retrospectively screened. Patients without a complete lipid profile consisting of total cholesterol (TC), triglycerides (TGC), high-density lipoprotein (HDL), low-density lipoprotein (LDL) and Lipoprotein(a) (Lp[a]) where excluded as well as patients with already initiated lipid-lowering therapy. 52 patients met the inclusion criteria. An age-adjusted ordinal regression model was applied to determine the association of each lipid fraction with the severity of PAD assessed as Fontaine classification. Results: The lipid profile of patients with PXE was unremarkable (TGC: 135.8±105.8 mg/dl; TC: 172.5±44.4 mg/dl; HDL: 63.0±18.2 mg/dl; Lp[a]: 64.7±93.5 nmol/l). Ordinal regression showed a significant association of Lp(a) with the severity of PAD with an odds ratio of 1.01 (1.00-1.02; p = 0.004), whereas the other fractions of the lipid profile had no significant influence. Conclusions: This study provides the largest evaluation of blood lipids up to now and the first characterization of Lp(a) levels in patients with PXE. We were able to provide first evidence of a correlation between elevated levels of Lp(a) and the severity of PAD. The present results suggest that determination of Lp(a) in early stages of PXE could help to identify patients at risk of rapid disease progression and with the need of intensified walking exercise training.
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Affiliation(s)
- Max Jonathan Stumpf
- Department of Internal Medicine II, Cardiology, Pneumology, and Angiology, University Hospital Bonn, Germany
| | - Tim Winkler
- Department of Internal Medicine II, Cardiology, Pneumology, and Angiology, University Hospital Bonn, Germany
| | - Marit Siebigteroth
- Department of Internal Medicine II, Cardiology, Pneumology, and Angiology, University Hospital Bonn, Germany
| | - Annemarie Lenzen
- Department of Internal Medicine II, Cardiology, Pneumology, and Angiology, University Hospital Bonn, Germany
| | - Leonie Weinhold
- Institute for Medical Biometry, Informatics, and Epidemiology, University Hospital Bonn, Germany
| | - Georg Nickenig
- Department of Internal Medicine II, Cardiology, Pneumology, and Angiology, University Hospital Bonn, Germany
| | - Doris Hendig
- Institute for Laboratory and Transfusion Medicine, Heart and Diabetes Centre North Rhine Westphalia, University Hospital of the Ruhr University Bochum, Bad Oeynhausen, Germany
| | - Dirk Skowasch
- Department of Internal Medicine II, Cardiology, Pneumology, and Angiology, University Hospital Bonn, Germany
| | - Nadjib Schahab
- Department of Internal Medicine II, Cardiology, Pneumology, and Angiology, University Hospital Bonn, Germany
| | - Christian A Schaefer
- Department of Internal Medicine II, Cardiology, Pneumology, and Angiology, University Hospital Bonn, Germany
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Rubera I, Clotaire L, Laurain A, Destere A, Martin L, Duranton C, Leftheriotis G. A Plasma Pyrophosphate Cutoff Value for Diagnosing Pseudoxanthoma Elasticum. Int J Mol Sci 2024; 25:6502. [PMID: 38928212 PMCID: PMC11203691 DOI: 10.3390/ijms25126502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 06/03/2024] [Accepted: 06/09/2024] [Indexed: 06/28/2024] Open
Abstract
Pseudoxanthoma elasticum (PXE) is a rare inherited systemic disease responsible for a juvenile peripheral arterial calcification disease. The clinical diagnosis of PXE is only based on a complex multi-organ phenotypic score and/or genetical analysis. Reduced plasma inorganic pyrophosphate concentration [PPi]p has been linked to PXE. In this study, we used a novel and accurate method to measure [PPi]p in one of the largest cohorts of PXE patients, and we reported the valuable contribution of a cutoff value to PXE diagnosis. Plasma samples and clinical records from two French reference centers for PXE (PXE Consultation Center, Angers, and FAVA-MULTI South Competent Center, Nice) were assessed. Plasma PPi were measured in 153 PXE and 46 non-PXE patients. The PPi concentrations in the plasma samples were determined by a new method combining enzymatic and ion chromatography approaches. The best match between the sensitivity and specificity (Youden index) for diagnosing PXE was determined by ROC analysis. [PPi]p were lower in PXE patients (0.92 ± 0.30 µmol/L) than in non-PXE patients (1.61 ± 0.33 µmol/L, p < 0.0001), corresponding to a mean reduction of 43 ± 19% (SD). The PPi cutoff value for diagnosing PXE in all patients was 1.2 µmol/L, with a sensitivity of 83.3% and a specificity of 91.1% (AUC = 0.93), without sex differences. In patients aged <50 years (i.e., the age period for PXE diagnosis), the cutoff PPi was 1.2 µmol/L (sensitivity, specificity, and AUC of 93%, 96%, and 0.97, respectively). The [PPi]p shows high accuracy for diagnosing PXE; thus, quantifying plasma PPi represents the first blood assay for diagnosing PXE.
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Affiliation(s)
- Isabelle Rubera
- University Côte d’Azur, CNRS, LP2M, Labex ICST, 06107 Nice, France; (I.R.); (L.C.); (A.L.); (G.L.)
| | - Laetitia Clotaire
- University Côte d’Azur, CNRS, LP2M, Labex ICST, 06107 Nice, France; (I.R.); (L.C.); (A.L.); (G.L.)
| | - Audrey Laurain
- University Côte d’Azur, CNRS, LP2M, Labex ICST, 06107 Nice, France; (I.R.); (L.C.); (A.L.); (G.L.)
| | - Alexandre Destere
- Pharmacology Department, Nice University Hospital, 06000 Nice, France
- FAVA-MULTI South Competence Center for Rare Arterial Calcifying Disease, Nice University Hospital, 06000 Nice, France
| | - Ludovic Martin
- PXE Reference Center, MAGEC Nord, Angers University Hospital, 49000 Angers, France;
| | - Christophe Duranton
- University Côte d’Azur, CNRS, LP2M, Labex ICST, 06107 Nice, France; (I.R.); (L.C.); (A.L.); (G.L.)
| | - Georges Leftheriotis
- University Côte d’Azur, CNRS, LP2M, Labex ICST, 06107 Nice, France; (I.R.); (L.C.); (A.L.); (G.L.)
- FAVA-MULTI South Competence Center for Rare Arterial Calcifying Disease, Nice University Hospital, 06000 Nice, France
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Dias MQ, Gouveia N, Félix R, Estrela-Silva S, Cabral D, Carvalho AL, Murta J, Silva R, Marques JP. Mutational spectrum and deep phenotyping in Pseudoxanthoma Elasticum: Findings from a Portuguese cohort. Eur J Ophthalmol 2024:11206721241247676. [PMID: 38602027 DOI: 10.1177/11206721241247676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2024]
Abstract
INTRODUCTION Pseudoxanthoma Elasticum (PXE) is a rare autosomal recessive disorder originated by disease-causing variants in ABCC6 gene. The purpose of this study was to characterize the genetic landscape, phenotypic spectrum and genotype-phenotype correlations in a Portuguese cohort of PXE patients. METHODS Multicentric cross-sectional study conducted in patients with a clinical and genetic diagnosis of PXE. Patients were identified using the IRD-PT registry (www.retina.com.pt). Genotypes were classified into 3 groups: (1) two truncating variants, (2) two non-truncating variants, or (3) mixed variants. Deep phenotyping comprised a comprehensive ophthalmologic and systemic evaluation using the updated Phenodex Score (PS). RESULTS Twenty-seven patients (23 families) were included. Sixteen different ABCC6 variants were identified, 7 of which are novel. The most prevalent variant was the nonsense variant c.3421C > T p.(Arg1141*) with an allele frequency of 18.5%. All patients exhibited ocular manifestations. Cutaneous manifestations were present in most patients (88.9%, n = 24/27). A PS score > E2 was strongly associated with worse visual acuity (B = -29.02; p = 0.001). No association was found between genotypic groups and cutaneous, vascular or cardiac manifestations. CONCLUSIONS This study describes the genetic spectrum of patients with PXE for the first time in a Portuguese cohort. A total of 16 different variants in ABCC6 were found (7 of which are novel), thus highlighting the genotypic heterogeneity associated with this condition and expanding its mutational spectrum. Still, no major genotype-phenotype associations could be established.
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Affiliation(s)
- Margarida Q Dias
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra, (CHUC), Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal
| | - Nuno Gouveia
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra, (CHUC), Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal
| | - Raquel Félix
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra, (CHUC), Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal
| | - Sérgio Estrela-Silva
- Ophthalmology Unit, Centro Hospitalar e Universitário de São João (CHUSJ), Porto, Portugal
- Department of Surgery and Physiology, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Diogo Cabral
- Ophthalmology Unit, Hospital Garcia de Orta (HGO), Lisbon, Portugal
| | - Ana Luísa Carvalho
- Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal
- Medical Genetics Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal
- University Clinic of Medical Genetics, Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
| | - Joaquim Murta
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra, (CHUC), Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal
- University Clinic of Ophthalmology, Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
| | - Rufino Silva
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra, (CHUC), Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal
- University Clinic of Ophthalmology, Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
| | - João Pedro Marques
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra, (CHUC), Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal
- University Clinic of Ophthalmology, Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
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Fésűs L, Kiss N, Farkas K, Plázár D, Pálla S, Navasiolava N, Róbert L, Wikonkál NM, Martin L, Medvecz M. Correlation of systemic involvement and presence of pathological skin calcification assessed by ex vivo nonlinear microscopy in Pseudoxanthoma elasticum. Arch Dermatol Res 2023; 315:1897-1908. [PMID: 36847829 PMCID: PMC10366029 DOI: 10.1007/s00403-023-02557-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 12/24/2022] [Accepted: 01/28/2023] [Indexed: 03/01/2023]
Abstract
Pseudoxanthoma elasticum (PXE (OMIM 264800)) is an autosomal recessive connective tissue disorder mainly caused by mutations in the ABCC6 gene. PXE results in ectopic calcification primarily in the skin, eye and blood vessels that can lead to blindness, peripheral arterial disease and stroke. Previous studies found correlation between macroscopic skin involvement and severe ophthalmological and cardiovascular complications. This study aimed to investigate correlation between skin calcification and systemic involvement in PXE. Ex vivo nonlinear microscopy (NLM) imaging was performed on formalin fixed, deparaffinized, unstained skin sections to assess the extent of skin calcification. The area affected by calcification (CA) in the dermis and density of calcification (CD) was calculated. From CA and CD, calcification score (CS) was determined. The number of affected typical and nontypical skin sites were counted. Phenodex + scores were determined. The relationship between the ophthalmological, cerebro- and cardiovascular and other systemic complications and CA, CD and CS, respectively, and skin involvement were analyzed. Regression models were built for adjustment to age and sex. We found significant correlation of CA with the number of affected typical skin sites (r = 0.48), the Phenodex + score (r = 0.435), extent of vessel involvement (V-score) (r = 0.434) and disease duration (r = 0.48). CD correlated significantly with V-score (r = 0.539). CA was significantly higher in patients with more severe eye (p = 0.04) and vascular (p = 0.005) complications. We found significantly higher CD in patients with higher V-score (p = 0.018), and with internal carotid artery hypoplasia (p = 0.045). Significant correlation was found between higher CA and the presence of macula atrophy (β = - 0.44, p = 0.032) and acneiform skin changes (β = 0.40, p = 0.047). Based on our results, the assessment of skin calcification pattern with nonlinear microscopy in PXE may be useful for clinicians to identify PXE patients who develop severe systemic complications.
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Affiliation(s)
- Luca Fésűs
- Department of Dermatology, Venereology and Dermatooncology, Semmelweis University, Mária Street 41, Budapest, 1085, Hungary
| | - Norbert Kiss
- Department of Dermatology, Venereology and Dermatooncology, Semmelweis University, Mária Street 41, Budapest, 1085, Hungary
| | - Klára Farkas
- Department of Dermatology, Venereology and Dermatooncology, Semmelweis University, Mária Street 41, Budapest, 1085, Hungary
| | - Dóra Plázár
- Department of Dermatology, Venereology and Dermatooncology, Semmelweis University, Mária Street 41, Budapest, 1085, Hungary
| | - Sára Pálla
- Department of Dermatology, Venereology and Dermatooncology, Semmelweis University, Mária Street 41, Budapest, 1085, Hungary
| | - Nastassia Navasiolava
- PXE National Reference Centre, Angers University Hospital, 4 Rue Larrey, 49100, Angers, France
| | - Lili Róbert
- Department of Dermatology, Venereology and Dermatooncology, Semmelweis University, Mária Street 41, Budapest, 1085, Hungary
| | - Norbert M Wikonkál
- Department of Dermatology, Venereology and Dermatooncology, Semmelweis University, Mária Street 41, Budapest, 1085, Hungary
| | - Ludovic Martin
- PXE National Reference Centre, Angers University Hospital, 4 Rue Larrey, 49100, Angers, France
| | - Márta Medvecz
- Department of Dermatology, Venereology and Dermatooncology, Semmelweis University, Mária Street 41, Budapest, 1085, Hungary.
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Inorganic Pyrophosphate Plasma Levels Are Decreased in Pseudoxanthoma Elasticum Patients and Heterozygous Carriers but Do Not Correlate with the Genotype or Phenotype. J Clin Med 2023; 12:jcm12051893. [PMID: 36902680 PMCID: PMC10003929 DOI: 10.3390/jcm12051893] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 01/29/2023] [Accepted: 02/10/2023] [Indexed: 03/08/2023] Open
Abstract
Pseudoxanthoma elasticum (PXE) is a rare ectopic calcification disorder affecting soft connective tissues that is caused by biallelic ABCC6 mutations. While the underlying pathomechanisms are incompletely understood, reduced circulatory levels of inorganic pyrophosphate (PPi)-a potent mineralization inhibitor-have been reported in PXE patients and were suggested to be useful as a disease biomarker. In this study, we explored the relation between PPi, the ABCC6 genotype and the PXE phenotype. For this, we optimized and validated a PPi measurement protocol with internal calibration that can be used in a clinical setting. An analysis of 78 PXE patients, 69 heterozygous carriers and 14 control samples revealed significant differences in the measured PPi levels between all three cohorts, although there was overlap between all groups. PXE patients had a ±50% reduction in PPi levels compared to controls. Similarly, we found a ±28% reduction in carriers. PPi levels were found to correlate with age in PXE patients and carriers, independent of the ABCC6 genotype. No correlations were found between PPi levels and the Phenodex scores. Our results suggest that other factors besides PPi are at play in ectopic mineralization, which limits the use of PPi as a predictive biomarker for severity and disease progression.
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Moore JM, Bell EL, Hughes RO, Garfield AS. ABC transporters: human disease and pharmacotherapeutic potential. Trends Mol Med 2023; 29:152-172. [PMID: 36503994 DOI: 10.1016/j.molmed.2022.11.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/24/2022] [Accepted: 11/01/2022] [Indexed: 12/12/2022]
Abstract
Adenosine triphosphate (ATP)-binding cassette (ABC) transporters are a 48-member superfamily of membrane proteins that actively transport a variety of biological substrates across lipid membranes. Their functional diversity defines an expansive involvement in myriad aspects of human biology. At least 21 ABC transporters underlie rare monogenic disorders, with even more implicated in the predisposition to and symptomology of common and complex diseases. Such broad (patho)physiological relevance places this class of proteins at the intersection of disease causation and therapeutic potential, underlining them as promising targets for drug discovery, as exemplified by the transformative CFTR (ABCC7) modulator therapies for cystic fibrosis. This review will explore the growing relevance of ABC transporters to human disease and their potential as small-molecule drug targets.
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Kozák E, Bartstra JW, de Jong PA, Mali WPTM, Fülöp K, Tőkési N, Pomozi V, Risseeuw S, Norel JOV, van Leeuwen R, Váradi A, Spiering W. Plasma Level of Pyrophosphate Is Low in Pseudoxanthoma Elasticum Owing to Mutations in the ABCC6 Gene, but It Does Not Correlate with ABCC6 Genotype. J Clin Med 2023; 12:jcm12031047. [PMID: 36769695 PMCID: PMC9917606 DOI: 10.3390/jcm12031047] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 01/04/2023] [Accepted: 01/22/2023] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Pseudoxanthoma elasticum (PXE), a monogenic disorder resulting in calcification affecting the skin, eyes and peripheral arteries, is caused by mutations in the ABCC6 gene, and is associated with low plasma inorganic pyrophosphate (PPi). It is unknown how ABCC6 genotype affects plasma PPi. METHODS We studied the association of ABCC6 genotype (192 patients with biallelic pathogenic ABCC6 mutations) and PPi levels, and its association with the severity of arterial and ophthalmological phenotypes. ABCC6 variants were classified as truncating or non-truncating, and three groups of the 192 patients were formed: those with truncating mutations on both chromosomes (n = 121), those with two non-truncating mutations (n = 10), and a group who had one truncating and one non-truncating ABCC6 mutation (n = 61). The hypothesis formulated before this study was that there was a negative association between PPi level and disease severity. RESULTS Our findings confirm low PPi in PXE compared with healthy controls (0.53 ± 0.15 vs. 1.13 ± 0.29 µM, p < 0.01). The PPi of patients correlated with increasing age (β: 0.05 µM, 95% CI: 0.03-0.06 per 10 years) and was higher in females (0.55 ± 0.17 vs. 0.51 ± 0.13 µM in males, p = 0.03). However, no association between PPi and PXE phenotypes was found. When adjusted for age and sex, no association between PPi and ABCC6 genotype was found. CONCLUSIONS Our data suggest that the relationship between ABCC6 mutations and reduced plasma PPi may not be as direct as previously thought. PPi levels varied widely, even in patients with the same ABCC6 mutations, further suggesting a lack of direct correlation between them, even though the ABCC6 protein-mediated pathway is responsible for ~60% of this metabolite in the circulation. We discuss potential factors that may perturb the expected associations between ABCC6 genotype and PPi and between PPi and disease severity. Our findings support the argument that predictions of pathogenicity made on the basis of mutations (or on the structure of the mutated protein) could be misleading.
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Affiliation(s)
- Eszter Kozák
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Center of Excellence, 1117 Budapest, Hungary
| | - Jonas W. Bartstra
- Department of Radiology, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Pim A. de Jong
- Department of Radiology, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Willem P. T. M. Mali
- Department of Radiology, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Krisztina Fülöp
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Center of Excellence, 1117 Budapest, Hungary
| | - Natália Tőkési
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Center of Excellence, 1117 Budapest, Hungary
| | - Viola Pomozi
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Center of Excellence, 1117 Budapest, Hungary
| | - Sara Risseeuw
- Department of Ophthalmology, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | | | - Redmer van Leeuwen
- Department of Ophthalmology, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - András Váradi
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Center of Excellence, 1117 Budapest, Hungary
| | - Wilko Spiering
- Department of Vascular Medicine, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
- Correspondence: ; Tel.: +31-88-7571188
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O’Brien C, Khursigara G, Huertas P, Leiro B, Molloy L, Nester C. Lifelong impact of ENPP1 Deficiency and the early onset form of ABCC6 Deficiency from patient or caregiver perspective. PLoS One 2022; 17:e0270632. [PMID: 35895733 PMCID: PMC9328542 DOI: 10.1371/journal.pone.0270632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 06/15/2022] [Indexed: 12/02/2022] Open
Abstract
The ectonucleotide pyrophosphatase/phosphodiesterase family member 1 (ENPP1) and ATP-binding cassette subfamily C member 6 (ABCC6) proteins play a prominent role in inhibiting ectopic calcification and arterial stenosis. Patients with ENPP1 Deficiency or infant onset ABCC6 Deficiency often present with pathological calcification, narrowed blood vessels, multiorgan dysfunction and high infant mortality. The heterogenous presentation and progression is well documented. Our objective was to characterize how these morbidities lead to burden of illness and poor quality of life across ages from the patient/caregiver perspective. Patients/caregivers were interviewed via phone using Institutional Review Board–approved questionnaires. Patient-reported outcomes were collected via validated instruments. Thirty-one caregivers and 7 patients participated: infant onset ABCC6 Deficiency, n = 6 (infants/children); ENPP1 Deficiency, n = 32 (13 infants, 12 children, 7 adults). ENPP1 and ABCC6-deficient children aged <8 years and aged 8–18 years reported poor school functioning (0.69 vs 0.72 effect size, respectively) and poor physical health (0.88 vs 1, respectively). In the total ENPP1 cohort, 72% (23/32) reported bone/joint pain and/or mobility/fatigue issues. Three of seven ENPP1-deficient adults reported moderate to severe pain (>4), as measured by the Brief Pain Inventory (BPI), that interfered with daily activities despite pain medication. Top reported burdens for caregivers of infants with ABCC6/ENPP1 Deficiencies included heart-related issues and hospitalizations. Treatment/medications, and hearing loss were the highest burdens reported by caregivers/families of the pediatric ENPP1 Deficiency cohort, whereas adults reported bone/joint pain and mobility impairment as the greatest burdens. Individuals with ENPP1 Deficiency or infant onset ABCC6 Deficiency experience lifelong morbidity causing substantial physical and emotional burden to patients/caregivers.
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Affiliation(s)
| | - Gus Khursigara
- Inozyme Pharma Inc, Boston, Massachusetts, United States of America
| | - Pedro Huertas
- Mirror Neuron Partners LLC and Harvard–MIT Program in Health Sciences and Technology, Boston, Massachusetts, United States of America
| | - Beth Leiro
- Inozyme Pharma Inc, Boston, Massachusetts, United States of America
| | - Liz Molloy
- GACI Global, Argyle, Texas, United States of America
| | - Catherine Nester
- Inozyme Pharma Inc, Boston, Massachusetts, United States of America
- * E-mail:
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10
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Lucci C, van den Beukel TC, Bartstra JW, Zwanenburg J, van der Kolk A, Takx R, Hendrikse J, Geerlings MI, Bos D, Spiering W, de Jong PA. Intracranial atherosclerosis in pseudoxanthoma elasticum: A case-control study. Atherosclerosis 2022; 350:19-24. [DOI: 10.1016/j.atherosclerosis.2022.04.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 04/08/2022] [Accepted: 04/13/2022] [Indexed: 11/25/2022]
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11
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Zheng A, Thibodeau PH. Commentary on Variants in the ABCC6 Gene Implicated in Pseudoxanthoma Elasticum, a Heritable Ectopic Mineralization Disorder. J Invest Dermatol 2022; 142:1002-1003. [DOI: 10.1016/j.jid.2022.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 02/16/2022] [Accepted: 02/16/2022] [Indexed: 11/25/2022]
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12
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Stumpf MJ, Schaefer CA, Mahn T, Wolf AE, Biener L, Hendig D, Nickenig G, Schahab N, Pizarro C, Skowasch D. Pulmonary affection of patients with Pseudoxanthoma elasticum: Long-term development and genotype-phenotype-correlation. Intractable Rare Dis Res 2022; 11:7-14. [PMID: 35261845 PMCID: PMC8898393 DOI: 10.5582/irdr.2021.01162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 02/03/2022] [Accepted: 02/09/2022] [Indexed: 11/05/2022] Open
Abstract
Pseudoxanthoma elasticum (PXE) is a rare, heritable disease caused by various, mainly recessively transmitted mutations in the ABCC6 gene. Due to calcification of soft connective tissue phenotypic hallmarks are progressive loss of vision, alternation of the skin and early onset atherosclerosis. Beside these main features patients also suffer from impaired alveolar diffusion. The present study focused on impaired lung functioning based on a large cohort of patients with PXE, its long-term development, and genotype-phenotype correlation. Retrospectively, 98 patients and 45 controls were enrolled. All patients underwent body plethysmography and carbon monoxide diffusion testing. Of 35 patients three or more body plethysmographic records were available for long-term analysis. For genotype-phenotype analysis ABCC6 genotypes were grouped as two missense, mixed, or two nonsense mutations. Patients with PXE showed significantly reduced vital capacity (p < 0.05), diffusion capacity (p < 0.01), and diffusion transfer coefficient (p < 0.05). Over a mean period of 38 months diffusion capacity (p < 0.05) and diffusion transfer coefficient (p < 0.01) dropped significantly whereas lung volumes remained unchanged. Genotype-phenotype correlation revealed no connection between gene variants and lung functioning. In conclusion, PXE is accompanied by progressive reduction of alveolar diffusion indicating progressive alterations of lung tissue. Genotype-phenotype correlation with genotypes sorted as missense and nonsense mutations do not explain impaired lung functioning.
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Affiliation(s)
- Max Jonathan Stumpf
- Department of Internal Medicine II, Cardiology, Pneumology and Angiology, University Hospital Bonn, Bonn, Germany
- Address correspondence to:Max Jonathan Stumpf, University Hospital of Bonn, Medical Department II, Cardiology, Pneumology, and Angiology, Venusberg-Campus 1, 53127 Bonn, Germany. E-mail:
| | - Christian Alexander Schaefer
- Department of Internal Medicine II, Cardiology, Pneumology and Angiology, University Hospital Bonn, Bonn, Germany
| | - Thorsten Mahn
- Department of Internal Medicine II, Cardiology, Pneumology and Angiology, University Hospital Bonn, Bonn, Germany
| | - Anna Elisabeth Wolf
- Department of Internal Medicine II, Cardiology, Pneumology and Angiology, University Hospital Bonn, Bonn, Germany
| | - Leonie Biener
- Department of Internal Medicine II, Cardiology, Pneumology and Angiology, University Hospital Bonn, Bonn, Germany
| | - Doris Hendig
- Institute for Laboratory and Transfusion Medicine, Heart and Diabetes Centre North Rhine Westphalia, University Hospital of the Ruhr University Bochum, Bad Oeynhausen, Germany
| | - Georg Nickenig
- Department of Internal Medicine II, Cardiology, Pneumology and Angiology, University Hospital Bonn, Bonn, Germany
| | - Nadjib Schahab
- Department of Internal Medicine II, Cardiology, Pneumology and Angiology, University Hospital Bonn, Bonn, Germany
| | - Carmen Pizarro
- Department of Internal Medicine II, Cardiology, Pneumology and Angiology, University Hospital Bonn, Bonn, Germany
| | - Dirk Skowasch
- Department of Internal Medicine II, Cardiology, Pneumology and Angiology, University Hospital Bonn, Bonn, Germany
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Therapy of Pseudoxanthoma Elasticum: Current Knowledge and Future Perspectives. Biomedicines 2021; 9:biomedicines9121895. [PMID: 34944710 PMCID: PMC8698611 DOI: 10.3390/biomedicines9121895] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/05/2021] [Accepted: 12/07/2021] [Indexed: 12/24/2022] Open
Abstract
Pseudoxanthoma elasticum (PXE) is a rare, genetic, metabolic disease with an estimated prevalence of between 1 per 25,000 and 56,000. Its main hallmarks are characteristic skin lesions, development of choroidal neovascularization, and early-onset arterial calcification accompanied by a severe reduction in quality-of-life. Underlying the pathology are recessively transmitted pathogenic variants of the ABCC6 gene, which results in a deficiency of ABCC6 protein. This results in reduced levels of peripheral pyrophosphate, a strong inhibitor of peripheral calcification, but also dysregulation of blood lipids. Although various treatment options have emerged during the last 20 years, many are either already outdated or not yet ready to be applied generally. Clinical physicians often are left stranded while patients suffer from the consequences of outdated therapies, or feel unrecognized by their attending doctors who may feel uncertain about using new therapeutic approaches or not even know about them. In this review, we summarize the broad spectrum of treatment options for PXE, focusing on currently available clinical options, the latest research and development, and future perspectives.
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Jin KW, Joo K, Woo SJ. Clinical Characterization of Korean Patients with Pseudoxanthoma Elasticum and Angioid Streaks. Genes (Basel) 2021; 12:genes12081207. [PMID: 34440381 PMCID: PMC8391950 DOI: 10.3390/genes12081207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 07/31/2021] [Accepted: 08/01/2021] [Indexed: 12/04/2022] Open
Abstract
This study aimed to characterize Korean patients with pseudoxanthoma elasticum (PXE) presenting with angioid streaks. Retinal phenotypes were longitudinally evaluated by multimodal ophthalmic imaging, and targeted gene panel sequencing for inherited retinal diseases was conducted. Seven subjects from unrelated families (median age, 51.2 years) were enrolled and followed for a median of 3.2 years. Four asymptomatic patients were significantly younger than three symptomatic patients with decreased visual acuity at presentation (mean age; 38.1 vs. 61.5 years, p = 0.020). The asymptomatic patients maintained good vision (20/32 or better) and had no choroidal neovascularization (CNV) over the observation period. The symptomatic patients showed additional reduction in visual acuity and bilateral CNV occurrence during the longitudinal follow-up. Pathogenic ABCC6 variants were identified in all patients, leading to a diagnosis of PXE. Heterozygous monoallelic variants were identified in four patients and compound heterozygous variants were detected in three patients. Nine ABCC6 variants were identified, including one novel variant, c.2035G>T [p.Glu679Ter]. This is the first genetic study of Korean patients with PXE.
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Boraldi F, Murro V, Lofaro FD, Mucciolo DP, Costa S, Pavese L, Quaglino D. Phenotypic Features and Genetic Findings in a Cohort of Italian Pseudoxanthoma Elasticum Patients and Update of the Ophthalmologic Evaluation Score. J Clin Med 2021; 10:2710. [PMID: 34205333 PMCID: PMC8235548 DOI: 10.3390/jcm10122710] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/11/2021] [Accepted: 06/16/2021] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Pseudoxanthoma elasticum (PXE) is a rare ectopic calcification genetic disease mainly caused by ABCC6 rare sequence variants. The clinical phenotype is characterized by typical dermatological, ophthalmological and cardiovascular manifestations, whose frequency and severity are differently reported in the literature. METHODS A retrospective study was performed on 377 PXE patients of Italian origin, clinically evaluated according to the Phenodex Index, who underwent ABCC6 biomolecular analyses. Moreover, 53 PXE patients were further characterized by in-depth ophthalmological examinations. RESULTS A total of 117 different ABCC6 rare sequence variants were detected as being spread through the whole gene. The severity of the clinical phenotype was dependent on age, but it was not influenced by gender or by the type of sequence variants. In-depth ophthalmological examinations focused on the incidences of coquille d'oeuf, comet lesions, pattern dystrophy-like lesions, optic disk drusen and posterior-pole atrophy. Conclusion: Given the large number of patients analyzed, we were able to better evaluate the occurrence of less frequent alterations (e.g., stroke, myocardial infarction, nephrolithiasis). A more detailed description of ophthalmological abnormalities allowed us to stratify patients and better evaluate disease progression, thus suggesting a further update of the PXE score system.
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Affiliation(s)
- Federica Boraldi
- Department of Life Science, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy; (F.B.); (F.D.L.); (S.C.)
| | - Vittoria Murro
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Eye Clinic, Viale Pieraccini 6, 50139 Florence, Italy; (V.M.); (D.P.M.); (L.P.)
| | - Francesco Demetrio Lofaro
- Department of Life Science, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy; (F.B.); (F.D.L.); (S.C.)
| | - Dario Pasquale Mucciolo
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Eye Clinic, Viale Pieraccini 6, 50139 Florence, Italy; (V.M.); (D.P.M.); (L.P.)
| | - Sonia Costa
- Department of Life Science, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy; (F.B.); (F.D.L.); (S.C.)
| | - Laura Pavese
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Eye Clinic, Viale Pieraccini 6, 50139 Florence, Italy; (V.M.); (D.P.M.); (L.P.)
| | - Daniela Quaglino
- Department of Life Science, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy; (F.B.); (F.D.L.); (S.C.)
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Shimada BK, Pomozi V, Zoll J, Kuo S, Martin L, Le Saux O. ABCC6, Pyrophosphate and Ectopic Calcification: Therapeutic Solutions. Int J Mol Sci 2021; 22:ijms22094555. [PMID: 33925341 PMCID: PMC8123679 DOI: 10.3390/ijms22094555] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 12/11/2022] Open
Abstract
Pathological (ectopic) mineralization of soft tissues occurs during aging, in several common conditions such as diabetes, hypercholesterolemia, and renal failure and in certain genetic disorders. Pseudoxanthoma elasticum (PXE), a multi-organ disease affecting dermal, ocular, and cardiovascular tissues, is a model for ectopic mineralization disorders. ABCC6 dysfunction is the primary cause of PXE, but also some cases of generalized arterial calcification of infancy (GACI). ABCC6 deficiency in mice underlies an inducible dystrophic cardiac calcification phenotype (DCC). These calcification diseases are part of a spectrum of mineralization disorders that also includes Calcification of Joints and Arteries (CALJA). Since the identification of ABCC6 as the “PXE gene” and the development of several animal models (mice, rat, and zebrafish), there has been significant progress in our understanding of the molecular genetics, the clinical phenotypes, and pathogenesis of these diseases, which share similarities with more common conditions with abnormal calcification. ABCC6 facilitates the cellular efflux of ATP, which is rapidly converted into inorganic pyrophosphate (PPi) and adenosine by the ectonucleotidases NPP1 and CD73 (NT5E). PPi is a potent endogenous inhibitor of calcification, whereas adenosine indirectly contributes to calcification inhibition by suppressing the synthesis of tissue non-specific alkaline phosphatase (TNAP). At present, therapies only exist to alleviate symptoms for both PXE and GACI; however, extensive studies have resulted in several novel approaches to treating PXE and GACI. This review seeks to summarize the role of ABCC6 in ectopic calcification in PXE and other calcification disorders, and discuss therapeutic strategies targeting various proteins in the pathway (ABCC6, NPP1, and TNAP) and direct inhibition of calcification via supplementation by various compounds.
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Affiliation(s)
- Briana K Shimada
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96817, USA
| | - Viola Pomozi
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, 1117 Budapest, Hungary
| | - Janna Zoll
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96817, USA
| | - Sheree Kuo
- Department of Pediatrics, Kapi'olani Medical Center for Women and Children, University of Hawaii, Honolulu, HI 96826, USA
| | - Ludovic Martin
- PXE Consultation Center, MAGEC Reference Center for Rare Skin Diseases, Angers University Hospital, 49100 Angers, France
- BNMI, CNRS 6214/INSERM 1083, University Bretagne-Loire, 49100 Angers, France
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96817, USA
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