From Clinical Diagnosis to the Discovery of Multigene Rare Sequence Variants in Pseudoxanthoma elasticum: A Case Report.
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ABSTRACT:
SUBMITTER: Lofaro FD
PROVIDER: S-EPMC8427021 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:A case of a patient with an early and severe visual impairment is described. Due to the occurrence of skin papules a suspect of pseudoxanthoma elasticum (PXE) was posed. PXE is a rare autosomal recessive disease clinically characterized by skin, cardiovascular and ocular manifestations, these last being those that most severely affect patients' quality of life. A whole exome sequencing approach focusing on 340 genes related to the calcification process and/or to inherited retinal diseases (IRDs) was performed. Rare monoallelic sequence variants in ABCA4, ABCC6, IMPG1, POC1B and RAX2 were found. The presence of calcified elastic fibers was assessed by ultrastructural analysis on a skin biopsy. Diagnosis of PXE was based on clinical, biomolecular and morphological results, although the additional involvement of several IRD genes is important to explain the unexpectedly severe ophthalmological phenotype of the patient also in prognostic and therapeutic perspectives. Data indicate that genetic screening using a wide-spectrum analysis approach is essential to assist ophthalmologists in improving patient counseling.
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Project description:Elastosis perforans serpiginosa (EPS), characterized by transepidermal elimination of fragmented elastic fibers, clinically presents as hyperkeratotic papules. EPS is classified into three types: (1) Idiopathic; (2) reactive, with associated connective tissue diseases such as pseudoxanthoma elasticum (PXE), Ehlers-Danlos syndrome, cutis laxa, Marfan syndrome, osteogenesis imperfecta, Down's syndrome; (3) the one that is induced by D-penicillamine. A rare association of EPS with PXE, which is primarily a defect of transmembrane transporter protein with accumulation of certain metabolic compounds and secondary calcification of elastic fibers has been documented in the literature. We report a case of PXE with associated lesions that were histopathologically compatible with EPS.
| S-EPMC4804577 | biostudies-literature
Project description:Pseudoxanthoma elasticum (PXE) is a rare multisystem disorder characterised by progressive calcification and fragmentation of elastic fibres. Recent genetic advances have identified the underlying defect to the ABCC6 gene on chromosome 16p13.1. Patients typically develop cutaneous, ocular, and cardiovascular manifestations but there is considerable phenotypic variability. The skin changes are usually apparent in adulthood, and rarely observed in childhood. Since the prognosis of PXE largely depends on the extent of extracutaneous organ involvement early recognition, intervention and lifestyle adjustments are important to reduce morbidity. First-degree family members should be carefully examined for any cutaneous or ophthalmologic features of PXE.
| S-EPMC1720489 | biostudies-other
Project description:Pseudoxanthoma elasticum (PXE) is a genetic metabolic disease with autosomal recessive inheritance caused by mutations in the ABCC6 gene. The lack of functional ABCC6 protein leads to ectopic mineralization that is most apparent in the elastic tissues of the skin, eyes and blood vessels. The clinical prevalence of PXE has been estimated at between 1 per 100,000 and 1 per 25,000, with slight female predominance. The first clinical sign of PXE is almost always small yellow papules on the nape and sides of the neck and in flexural areas. The papules coalesce, and the skin becomes loose and wrinkled. The mid-dermal elastic fibers are short, fragmented, clumped and calcified. Dystrophic calcification of Bruch's membrane, revealed by angioid streaks, may trigger choroidal neovascularization and, ultimately, loss of central vision and blindness in late-stage disease. Lesions in small and medium-sized artery walls may result in intermittent claudication and peripheral artery disease. Cardiac complications (myocardial infarction, angina pectoris) are thought to be relatively rare but merit thorough investigation. Ischemic strokes have been reported. PXE is a metabolic disease in which circulating levels of an anti-mineralization factor are low. There is good evidence to suggest that the factor is inorganic pyrophosphate (PPi), and that the circulating low levels of PPi and decreased PPi/Pi ratio result from the lack of ATP release by hepatocytes harboring the mutant ABCC6 protein. However, the substrate(s) bound, transported or modulated by the ABCC6 protein remain unknown. More than 300 sequence variants of the ABCC6 gene have been identified. There is no cure for PXE; the main symptomatic treatments are vascular endothelial growth factor inhibitor therapy (for ophthalmic manifestations), lifestyle, lipid-lowering and dietary measures (for reducing vascular risk factors), and vascular surgery (for severe cardiovascular manifestations). Future treatment options may include gene therapy/editing and pharmacologic chaperone therapy.
| S-EPMC5424392 | biostudies-literature
Project description:A number of beta-thalassemia patients, independently from the type of beta-thalassemia (β0 or β+) and blood transfusion requirements, may develop, after puberty, dermal, cardiovascular, and ocular complications associated with an ectopic mineralization phenotype similar to that observed in another rare genetic disorder, namely, Pseudoxanthoma elasticum (PXE). To date, the causes of these alterations in beta-thalassemia patients are not known, but it has been suggested that they could be the consequence of oxidative stress-driven epigenetic regulatory mechanisms producing an ABCC6 down-regulation. Since, in the last years, several genes have been associated to the ectopic mineralization phenotype, this study, for the first time, applied, on beta-thalassemia patients with ectopic mineralization phenotype, a multigene testing strategy. Selection of genes to be analyzed was done on the basis of (i) their genetic involvement in calcification diseases or (ii) their role in calcium-phosphate equilibrium. Although, due to the rarity of these conditions, a limited number of patients was analyzed, the detection of pathogenic variants represents the proof of concept that PXE and beta-thalassemia traits co-occur on a genetic basis and that, in addition to causative mutations, functional polymorphisms may further influence connective tissue manifestations. The use of a multigene-based next-generation sequencing represents a useful time- and cost-effective approach, allowing to identify sequence variants that might improve prognostic assessment and better management of these patients, especially in the current era of precision medicine aiming to identify individual optimal care based on a unique personal profile.
| S-EPMC6989569 | biostudies-literature
Project description:The molecular etiology of pseudoxanthoma elasticum (PXE), an autosomal recessive connective tissue disorder, has become increasingly complex as not only mutations in ATP-binding cassette family C member 6 (ABCC6) but also ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) and gamma-glutamyl carboxylase (GGCX) can cause resembling phenotypes. Identification of modifier genes, such as vascular endothelial growth factor A, has further contributed to the molecular heterogeneity of PXE. In such heterogeneous diseases, next-generation sequencing (NGS) allows to perform mutation screening of several genes in a single reaction. We explored whole-exome sequencing (WES) as an efficient diagnostic tool to identify the causal mutations in ABCC6, GGCX, ENPP1, and vitamin K epoxide reductase complex, subunit 1 (VKORC1) in 16 PXE patients. WES identified a causal ABCC6 mutation in 30 out of 32 alleles and one GGCX mutation, whereas no causal mutations in ENPP1 or VKORC1 were detected. Exomes with insufficient reads (?20 depth) for the four genes and patients with single mutations were further evaluated by Sanger sequencing (SS), but no additional mutations were found. The potential of WES compared with targeted NGS is the ease to examine target genes and the opportunity to search for novel genes when targeted analysis is negative. Together with low cost, rapid and less laborious workflow, we conclude that WES complemented with SS can provide a tiered approach to molecular diagnostics of PXE.
| S-EPMC4378258 | biostudies-literature
Project description:ImportanceAcute retinopathy may partly explain variable disease manifestation and vision loss in patients with pseudoxanthoma elasticum (PXE). The diagnosis of this likely autoimmune process may inform patient counseling and treatment approaches.ObjectiveTo characterize acute retinopathy in patients with PXE as a disease manifestation that may be associated with profound visual impairment.Design, setting, and participantsThis single-center case series was conducted from May 2013 to October 2018. It used the patient database of the Department of Ophthalmology at the University of Bonn, a referral center for PXE in Germany. Patients at this center with genetically confirmed PXE and who met the inclusion criteria were included (n = 9). Patients underwent multimodal retinal imaging, including fundus photography, fundus autofluorescence (AF), optical coherence tomography (OCT), fluorescein angiography (FA), and indocyanine green angiography (ICGA); in select cases, electroretinography as well as antiretinal and anti-retinal pigment epithelium (RPE) antibody testing were also used.Main outcomes and measuresClinical presentation and disease course.ResultsNine patients (8 [89%] female; mean [range] age, 43 [19-55] years) with acute retinopathy were identified in a cohort of 167 consecutive patients with PXE (frequency of 5%). Symptoms ranged from light sensations or metamorphopsia to profound vision loss. Visual acuity was reduced in 6 patients (67%), ranging from a best-corrected visual acuity of 20/30 to perception of hand movements at manifestation. All patients revealed characteristic fundus features with temporary appearance of partly confluent outer retinal whitish dots at the posterior pole, which corresponded to areas of hyperautofluorescence on fundus AF, loss of the ellipsoid band on OCT, and associated scotomata. The FA and late-phase ICGA imaging showed associated hyperfluorescence and hypocyanescence. Electroretinography revealed a variable reduction of amplitudes. Changes were fully reversible within 1 month in 3 of 8 patients with available follow-up data. Of the remaining 5 patients, 3 had a prolonged and likely permanent vision loss (observation period, 1-64 months) mainly owing to central subretinal hyperreflective material originating from angioid streaks. In 4 (67%) of 6 tested, antiretinal and/or anti-RPE antibodies were detected.Conclusions and relevanceAcute retinopathy in patients with PXE may occur, with symptoms ranging from short-term, reversible alterations to irreversible vision loss; these findings contribute to understanding the variable ocular disease progression in PXE and provide insights into the autoimmune phenomena of the posterior pole.
| S-EPMC6692665 | biostudies-literature
Project description:Renal leiomyosarcomas (LMS) are extremely rare neoplasms with aggressive behaviour and poor survival prognosis. The most frequent somatic events in leiomyosarcomas are mutations in TP53, RB1, ATRX and PTEN genes, chromosomal instability and chromoanagenesis. By using chromosomal microarray analysis we identified monosomy of chromosomes 3 and 11, gain of Xp (ATRX) arm and three chromoanasynthesis regions (6q21-q27, 7p22.3-p12.1 and 12q13.11-q21.2), with MDM2 and CDK4 oncogenes copy number gains, whereas no CNVs or tumor specific SNVs in TP53, RB1 and PTEN genes were observed.
2020-06-04 | GSE151766 | GEO
Project description:Pseudoxanthoma elasticum (PXE) is a pleiotropic multisystem disorder affecting skin, eyes, and the cardiovascular system with progressive pathological mineralization. It is caused by mutations in the ABCC6 gene expressed primarily in the liver and kidneys, and at very low levels, if at all, in tissues affected by PXE. A question has arisen regarding the pathomechanism of PXE, particularly the "metabolic" versus the "PXE cell" hypotheses. We examined a murine PXE model (Abcc6(-/-)) by transplanting muzzle skin from knockout (KO) and wild-type (WT) mice onto the back of WT and KO mice using mineralization of the connective tissue capsule surrounding the vibrissae as an early phenotypic biomarker. Grafting of WT mouse muzzle skin onto the back of KO mice resulted in mineralization of vibrissae, whereas grafting KO mouse muzzle skin onto WT mice did not. Thus, these findings implicate circulatory factors as a critical component of the mineralization process. This mouse grafting model supports the notion that PXE is a systemic metabolic disorder with secondary mineralization of connective tissues and that the mineralization process can be countered or even reversed by changes in the homeostatic milieu.
| S-EPMC3169309 | biostudies-literature
Project description:Pseudoxanthoma Elasticum (PXE) is an inherited disease characterized by elastic fiber calcification in the eyes, the skin and the cardiovascular system. PXE results from mutations in ABCC6 that encodes an ABC transporter primarily expressed in the liver and kidneys. It took nearly 15 years after identifying the gene to better understand the etiology of PXE. ABCC6 function facilitates the efflux of ATP, which is sequentially hydrolyzed by the ectonucleotidases ENPP1 and CD73 into pyrophosphate (PPi) and adenosine, both inhibitors of calcification. PXE, together with General Arterial Calcification of Infancy (GACI caused by ENPP1 mutations) as well as Calcification of Joints and Arteries (CALJA caused by NT5E/CD73 mutations), forms a disease continuum with overlapping phenotypes and shares steps of the same molecular pathway. The explanation of these phenotypes place ABCC6 as an upstream regulator of a purinergic pathway (ABCC6 → ENPP1 → CD73 → TNAP) that notably inhibits mineralization by maintaining a physiological Pi/PPi ratio in connective tissues. Based on a review of the literature and our recent experimental data, we suggest that PXE (and GACI/CALJA) be considered as an authentic "purinergic disease". In this article, we recapitulate the pathobiology of PXE and review molecular and physiological data showing that, beyond PPi deficiency and ectopic calcification, PXE is associated with wide and complex alterations of purinergic systems. Finally, we speculate on the future prospects regarding purinergic signaling and other aspects of this disease.
| S-EPMC10886499 | biostudies-literature