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Musalkova D, Majer F, Kuchar L, Luksan O, Asfaw B, Vlaskova H, Storkanova G, Reboun M, Poupetova H, Jahnova H, Hulkova H, Ledvinova J, Dvorakova L, Sikora J, Jirsa M, Vanier MT, Hrebicek M. Transcript, protein, metabolite and cellular studies in skin fibroblasts demonstrate variable pathogenic impacts of NPC1 mutations. Orphanet J Rare Dis 2020; 15:85. [PMID: 32248828 PMCID: PMC7132889 DOI: 10.1186/s13023-020-01360-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/17/2020] [Indexed: 12/18/2022] Open
Abstract
Background Niemann-Pick type C (NP-C) is a rare neurovisceral genetic disorder caused by mutations in the NPC1 or the NPC2 gene. NPC1 is a multipass-transmembrane protein essential for egress of cholesterol from late endosomes/lysosomes. To evaluate impacts of NPC1 mutations, we examined fibroblast cultures from 26 NP-C1 patients with clinical phenotypes ranging from infantile to adult neurologic onset forms. The cells were tested with multiple assays including NPC1 mRNA expression levels and allele expression ratios, assessment of NPC1 promoter haplotypes, NPC1 protein levels, cellular cholesterol staining, localization of the mutant NPC1 proteins to lysosomes, and cholesterol/cholesteryl ester ratios. These results were correlated with phenotypes of the individual patients. Results Overall we identified 5 variant promoter haplotypes. Three of them showed reporter activity decreased down to 70% of the control sequence. None of the haplotypes were consistently associated with more severe clinical presentation of NP-C. Levels of transcripts carrying null NPC1 alleles were profoundly lower than levels of the missense variants. Low levels of the mutant NPC1 protein were identified in most samples. The protein localised to lysosomes in cultures expressing medium to normal NPC1 levels. Fibroblasts from patients with severe infantile phenotypes had higher cholesterol levels and higher cholesterol/cholesteryl ester ratios. On the contrary, cell lines from patients with juvenile and adolescent/adult phenotypes showed values comparable to controls. Conclusion No single assay fully correlated with the disease severity. However, low residual levels of NPC1 protein and high cholesterol/cholesteryl ester ratios associated with severe disease. The results suggest not only low NPC1 expression due to non-sense mediated decay or low mutant protein stability, but also dysfunction of the stable mutant NPC1 as contributors to the intracellular lipid transport defect.
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Affiliation(s)
- Dita Musalkova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Filip Majer
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic.
| | - Ladislav Kuchar
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Ondrej Luksan
- Laboratory of Experimental Hepatology, Institute of Clinical and Experimental Medicine, Prague, Czech Republic
| | - Befekadu Asfaw
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Hana Vlaskova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Gabriela Storkanova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Martin Reboun
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Helena Poupetova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Helena Jahnova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Helena Hulkova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Jana Ledvinova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Lenka Dvorakova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Jakub Sikora
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Milan Jirsa
- Laboratory of Experimental Hepatology, Institute of Clinical and Experimental Medicine, Prague, Czech Republic
| | - Marie T Vanier
- INSERM U820, Lyon, France.,Laboratoire Gillet-Mérieux, Lyon University Hospitals (HCL), Lyon, France
| | - Martin Hrebicek
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic.
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Dvorakova L, Vlaskova H, Sarajlija A, Ramadza DP, Poupetova H, Hruba E, Hlavata A, Bzduch V, Peskova K, Storkanova G, Kecman B, Djordjevic M, Baric I, Fumic K, Barisic I, Reboun M, Kulhanek J, Zeman J, Magner M. Genotype-phenotype correlation in 44 Czech, Slovak, Croatian and Serbian patients with mucopolysaccharidosis type II. Clin Genet 2017; 91:787-796. [PMID: 27883178 DOI: 10.1111/cge.12927] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 11/07/2016] [Accepted: 11/17/2016] [Indexed: 11/26/2022]
Abstract
Mucopolysaccharidosis type II (Hunter syndrome, MPS II, OMIM 309900) is an X-linked lysosomal storage disorder caused by deficiency of iduronate-2-sulfatase (IDS). We analyzed clinical and laboratory data from 44 Slavic patients with this disease. In total, 21 Czech, 7 Slovak, 9 Croatian and 7 Serbian patients (43 M/1 F) were included in the study (median age 11.0 years, range 1.2-43 years). Birth prevalence ranged from 1:69,223 (Serbia) to 1:192,626 (Czech Rep.). In the majority of patients (71%), the disease manifested in infancy. Cognitive functions were normal in 10 patients. Four, six and 24 patients had mild, moderate, and severe developmental delay, respectively, typically subsequent to developmental regression (59%). Residual enzyme activity showed no predictive value, and estimation of glycosaminoglycans (GAGs) had only limited importance for prognosis. Mutation analysis performed in 36 families led to the identification of 12 novel mutations, eight of which were small deletions/insertions. Large deletions/rearrangements and all but one small deletion/insertion led to a severe phenotype. This genotype-phenotype correlation was also identified in six cases with recurrent missense mutations. Based on patient genotype, the severity of the disease may be predicted with high probability in approximately half of MPS II patients.
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Affiliation(s)
- L Dvorakova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - H Vlaskova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - A Sarajlija
- Department of Metabolism and Clinical Genetics, Mother and Child Health Care Institute of Serbia, Belgrade, Serbia.,School of Medicine, University of Belgrade, Belgrade, Serbia
| | - D P Ramadza
- Department of Pediatrics, University Hospital Center, Zagreb, Croatia
| | - H Poupetova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - E Hruba
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - A Hlavata
- 2nd Department of Pediatrics, Comenius University Medical School in Bratislava University Children's Hospital, Bratislava, Slovakia
| | - V Bzduch
- 1st Department of Pediatrics, Comenius University Medical School in Bratislava University Children's Hospital, Bratislava, Slovakia
| | - K Peskova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - G Storkanova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - B Kecman
- Department of Metabolism and Clinical Genetics, Mother and Child Health Care Institute of Serbia, Belgrade, Serbia
| | - M Djordjevic
- Department of Metabolism and Clinical Genetics, Mother and Child Health Care Institute of Serbia, Belgrade, Serbia.,School of Medicine, University of Belgrade, Belgrade, Serbia
| | - I Baric
- Department of Pediatrics, University Hospital Center and University of Zagreb, School of Medicine, Zagreb, Croatia
| | - K Fumic
- Department of Laboratory Diagnostics, University Hospital Centre Zagreb and School of Medicine, Zagreb, Croatia
| | - I Barisic
- Department of Paediatrics, Children's Hospital Zagreb, School of Medicine, Zagreb, Croatia
| | - M Reboun
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - J Kulhanek
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - J Zeman
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic.,Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - M Magner
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
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Stiburkova B, Miyata H, Závada J, Tomčík M, Pavelka K, Storkanova G, Toyoda Y, Takada T, Suzuki H. Novel dysfunctional variant inABCG2as a cause of severe tophaceous gout: biochemical, molecular genetics and functional analysis. Rheumatology (Oxford) 2015; 55:191-4. [DOI: 10.1093/rheumatology/kev350] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Musalkova D, Minks J, Storkanova G, Dvorakova L, Hrebicek M. Identification of novel informative loci for DNA-based X-inactivation analysis. Blood Cells Mol Dis 2014; 54:210-6. [PMID: 25455112 DOI: 10.1016/j.bcmd.2014.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Revised: 02/23/2014] [Accepted: 04/23/2014] [Indexed: 01/19/2023]
Abstract
The HUMARA assay, the most common method for evaluation of X-inactivation skewing in blood cells, has been reported to be usable in only about 80% of females, emphasizing the need for alternative methods for testing of HUMARA-uninformative individuals. We conducted an in silico search for potentially polymorphic tri-to-hexanucleotide repeats in the proximity of CpG islands located in 5' regions of X-chromosome genes to design five candidate assays (numbered I, II, III, IV, and V) combining methylation-specific restriction digest with PCR amplification in a manner similar to the HUMARA assay. The results obtained by these assays in 100 healthy females were compared to X-inactivation skewing measured by the AR-MSP method which is based on methylation-specific PCR amplification of the first exon of the AR gene. On the basis of statistical evidence, three of the novel assays (II, IV, and V), which were informative in 18%, 61%, and 55% of females in the cohort, respectively, may be used as alternatives or conjointly with the HUMARA assay to improve its reliability. The three new assays were combined with the HUMARA assay into a novel X-inactivation test leading to the increase of informative females in the cohort from 67% to 96%.
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Affiliation(s)
- Dita Musalkova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic
| | - Jakub Minks
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic
| | - Gabriela Storkanova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic
| | - Lenka Dvorakova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic
| | - Martin Hrebicek
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic.
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Storkanova G, Vlaskova H, Chuzhanova N, Zeman J, Stranecky V, Majer F, Peskova K, Luksan O, Jirsa M, Hrebicek M, Dvorakova L. Ornithine carbamoyltransferase deficiency: molecular characterization of 29 families. Clin Genet 2013; 84:552-9. [DOI: 10.1111/cge.12085] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 12/21/2012] [Accepted: 12/21/2012] [Indexed: 11/30/2022]
Affiliation(s)
- G Storkanova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine; Charles University in Prague, and General University Hospital in Prague; Czech Republic
| | - H Vlaskova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine; Charles University in Prague, and General University Hospital in Prague; Czech Republic
| | - N Chuzhanova
- School of Science and Technology; Nottingham Trent University; Nottingham NG11 8NS UK
| | - J Zeman
- Department of Paediatrics and Adolescent Medicine; First Faculty of Medicine, Charles University in Prague, and General University Hospital in Prague; Czech Republic
| | - V Stranecky
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine; Charles University in Prague, and General University Hospital in Prague; Czech Republic
| | - F Majer
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine; Charles University in Prague, and General University Hospital in Prague; Czech Republic
| | - K Peskova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine; Charles University in Prague, and General University Hospital in Prague; Czech Republic
| | - O Luksan
- Laboratory of Experimental Hepatology; Institute for Clinical and Experimental Medicine (IKEM); Prague Czech Republic
| | - M Jirsa
- Laboratory of Experimental Hepatology; Institute for Clinical and Experimental Medicine (IKEM); Prague Czech Republic
| | - M Hrebicek
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine; Charles University in Prague, and General University Hospital in Prague; Czech Republic
| | - L Dvorakova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine; Charles University in Prague, and General University Hospital in Prague; Czech Republic
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Luksan O, Jirsa M, Eberova J, Minks J, Treslova H, Bouckova M, Storkanova G, Vlaskova H, Hrebicek M, Dvorakova L. Disruption of OTC promoter-enhancer interaction in a patient with symptoms of ornithine carbamoyltransferase deficiency. Hum Mutat 2010; 31:E1294-303. [PMID: 20127982 DOI: 10.1002/humu.21215] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In a female patient with signs of ornithine carbamoyltransferase deficiency (OTCD), the only variation found was a heterozygous single nucleotide substitution c.-366A>G. Determination of transcription start sites of human OTC 95, 119 and 169 bp upstream of the initiation codon located the variation upstream of the 5'-untranslated region. We predicted the human promoter and enhancer elements from homology with rat and mouse, performed function analysis of both regulatory regions and assessed the impact of the promoter variation in functional studies using dual luciferase reporter assay. Our data indicate that: (i) Full transcriptional activity of human OTC promoter depends on an upstream enhancer, as do the rodent promoters. (ii) The promoter variation c.-366A>G does not affect the function of the promoter alone but it disrupts the interaction of the promoter with the enhancer. (iii) The promoter-enhancer interaction contributes to tissue specific expression of OTC in the liver. We conclude that mutations in the regulatory regions of OTC can lead to OTCD and should be included in genetic testing.
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Affiliation(s)
- Ondrej Luksan
- Laboratory of Experimental Hepatology, Institute for Clinical and Experimental Medicine, Prague
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