Publications by authors named "Gert Scheper"

59 Publications

Safety and Efficacy of Single-Dose Ad26.COV2.S Vaccine against Covid-19.

N Engl J Med 2021 Apr 21. Epub 2021 Apr 21.

From Janssen Vaccines and Prevention, Leiden, the Netherlands (J. Sadoff, G. Shukarev, G. Scheper, M.L.G., H.S., J.V.H., M.D.); South African Research Council, Cape Town, South Africa (G.G.); Janssen Research and Development, Beerse, Belgium (A.V., C.T., H.F., B.S., K.O., M.F.R., N.C., T.T., K.H., J.R.G., F.S.); Janssen Research and Development, Spring House, PA (V.C.); Evandro Chagas National Institute of Infectious Diseases-Fiocruz, Rio de Janeiro (B.G.); the University of Alabama at Birmingham, Birmingham (P.A.G.); the National Institute of Allergy and Infectious Diseases, Rockville (K.L.T., M.A.M.), Walter Reed Army Institute of Research, Silver Spring (M.L.R.), and the Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore (K.M.N.) - all in Maryland; Biomedical Advanced Research and Development Authority, Washington, DC (J.T.); the Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Boston (D.H.B.); Janssen Research and Development, Raritan, NJ (J. Stoddard); and Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle (L.C.).

Background: The Ad26.COV2.S vaccine is a recombinant, replication-incompetent human adenovirus type 26 vector encoding full-length severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein in a prefusion-stabilized conformation.

Methods: In an international, randomized, double-blind, placebo-controlled, phase 3 trial, we randomly assigned adult participants in a 1:1 ratio to receive a single dose of Ad26.COV2.S (5×10 viral particles) or placebo. The primary end points were vaccine efficacy against moderate to severe-critical coronavirus disease 2019 (Covid-19) with an onset at least 14 days and at least 28 days after administration among participants in the per-protocol population who had tested negative for SARS-CoV-2. Safety was also assessed.

Results: The per-protocol population included 19,630 SARS-CoV-2-negative participants who received Ad26.COV2.S and 19,691 who received placebo. Ad26.COV2.S protected against moderate to severe-critical Covid-19 with onset at least 14 days after administration (116 cases in the vaccine group vs. 348 in the placebo group; efficacy, 66.9%; adjusted 95% confidence interval [CI], 59.0 to 73.4) and at least 28 days after administration (66 vs. 193 cases; efficacy, 66.1%; adjusted 95% CI, 55.0 to 74.8). Vaccine efficacy was higher against severe-critical Covid-19 (76.7% [adjusted 95% CI, 54.6 to 89.1] for onset at ≥14 days and 85.4% [adjusted 95% CI, 54.2 to 96.9] for onset at ≥28 days). Despite 86 of 91 cases (94.5%) in South Africa with sequenced virus having the 20H/501Y.V2 variant, vaccine efficacy was 52.0% and 64.0% against moderate to severe-critical Covid-19 with onset at least 14 days and at least 28 days after administration, respectively, and efficacy against severe-critical Covid-19 was 73.1% and 81.7%, respectively. Reactogenicity was higher with Ad26.COV2.S than with placebo but was generally mild to moderate and transient. The incidence of serious adverse events was balanced between the two groups. Three deaths occurred in the vaccine group (none were Covid-19-related), and 16 in the placebo group (5 were Covid-19-related).

Conclusions: A single dose of Ad26.COV2.S protected against symptomatic Covid-19 and asymptomatic SARS-CoV-2 infection and was effective against severe-critical disease, including hospitalization and death. Safety appeared to be similar to that in other phase 3 trials of Covid-19 vaccines. (Funded by Janssen Research and Development and others; ENSEMBLE ClinicalTrials.gov number, NCT04505722.).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1056/NEJMoa2101544DOI Listing
April 2021

Interim Results of a Phase 1-2a Trial of Ad26.COV2.S Covid-19 Vaccine.

N Engl J Med 2021 05 13;384(19):1824-1835. Epub 2021 Jan 13.

From Janssen Vaccines and Prevention, Leiden, the Netherlands (J. Sadoff, M.L.G., G. Shukarev, A.M.G., J. Stoop, S.T., E.C., G. Scheper, J. Hendriks, M.D., J.V.H., H.S.); Janssen Research and Development, Beerse (D.H., C.T., F.S.), Janssen Clinical Pharmacology Unit, Merksem (W.V.D.), the Center for Vaccinology, Ghent University, Gent (I.L.-R.), SGS Life Sciences (P.-J.B.) and the Center for the Evaluation of Vaccination, University of Antwerp (P.V.D.), Antwerp, and the Center for Clinical Pharmacology, University Hospitals Leuven, Leuven (J. de Hoon) - all in Belgium; Optimal Research, Melbourne, FL (M.K.); the Alliance for Multispecialty Research, Knoxville, TN (W.S.); the Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Boston (K.E.S., D.H.B.); and the Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle (S.C.D.R., K.W.C., M.J.M.).

Background: Efficacious vaccines are urgently needed to contain the ongoing coronavirus disease 2019 (Covid-19) pandemic of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A candidate vaccine, Ad26.COV2.S, is a recombinant, replication-incompetent adenovirus serotype 26 (Ad26) vector encoding a full-length and stabilized SARS-CoV-2 spike protein.

Methods: In this multicenter, placebo-controlled, phase 1-2a trial, we randomly assigned healthy adults between the ages of 18 and 55 years (cohort 1) and those 65 years of age or older (cohort 3) to receive the Ad26.COV2.S vaccine at a dose of 5×10 viral particles (low dose) or 1×10 viral particles (high dose) per milliliter or placebo in a single-dose or two-dose schedule. Longer-term data comparing a single-dose regimen with a two-dose regimen are being collected in cohort 2; those results are not reported here. The primary end points were the safety and reactogenicity of each dose schedule.

Results: After the administration of the first vaccine dose in 805 participants in cohorts 1 and 3 and after the second dose in cohort 1, the most frequent solicited adverse events were fatigue, headache, myalgia, and injection-site pain. The most frequent systemic adverse event was fever. Systemic adverse events were less common in cohort 3 than in cohort 1 and in those who received the low vaccine dose than in those who received the high dose. Reactogenicity was lower after the second dose. Neutralizing-antibody titers against wild-type virus were detected in 90% or more of all participants on day 29 after the first vaccine dose (geometric mean titer [GMT], 212 to 354), regardless of vaccine dose or age group, and reached 96% by day 57 with a further increase in titers (GMT, 288 to 488) in cohort 1a. Titers remained stable until at least day 71. A second dose provided an increase in the titer by a factor of 2.6 to 2.9 (GMT, 827 to 1266). Spike-binding antibody responses were similar to neutralizing-antibody responses. On day 15, CD4+ T-cell responses were detected in 76 to 83% of the participants in cohort 1 and in 60 to 67% of those in cohort 3, with a clear skewing toward type 1 helper T cells. CD8+ T-cell responses were robust overall but lower in cohort 3.

Conclusions: The safety and immunogenicity profiles of Ad26.COV2.S support further development of this vaccine candidate. (Funded by Johnson & Johnson and the Biomedical Advanced Research and Development Authority of the Department of Health and Human Services; COV1001 ClinicalTrials.gov number, NCT04436276.).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1056/NEJMoa2034201DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7821985PMC
May 2021

Oral HPV16 DNA as a screening tool to detect early oropharyngeal squamous cell carcinoma.

Cancer Sci 2020 Oct 7;111(10):3854-3861. Epub 2020 Aug 7.

Saliva & Liquid Biopsy Translational Laboratory, The School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia.

Given that oropharyngeal squamous cell carcinoma (OPSCC) have now surpassed cervical cancer as the most common human papillomavirus (HPV)-driven cancer, there is an interest in developing non-invasive predictive biomarkers to early detect HPV-driven OPSCC. In total, 665 cancer-free individuals were recruited from Queensland, Australia. Oral HPV16 DNA positivity in those individuals was determined by our in-house developed sensitive PCR method. Individuals with (n = 9) or without (n = 12) oral HPV16 infections at baseline were followed for a median duration of 24 mo. Individuals with persistent oral HPV16 infection (≥ 30 mo) were invited for clinical examination of their oral cavity and oropharynx by an otolaryngologist. Oral HPV16 DNA was detected in 12 out of 650 cancer-free individuals (1.8%; 95% confidence interval [CI]: 1.0-3.2). Of the 3 individuals with persistent oral HPV16 infection, the first individual showed no clinical evidence of pathology. The second individual was diagnosed with a 2 mm invasive squamous cell carcinoma (T1N0M0) positive for both p16INK4a expression and HPV16 DNA. The third individual was found to have a mildly dysplastic lesion in the tonsillar region that was negative for p16INK4a expression and HPV16 DNA and she continues to have HPV16 DNA in her saliva. Taken together, our data support the value of using an oral HPV16 DNA assay as a potential screening tool for the detection of microscopic HPV-driven OPSCC. Larger multicenter studies across various geographic regions recruiting populations at a higher risk of developing HPV-driven OPSCC are warranted to extend and confirm the results of the current investigation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/cas.14585DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7540991PMC
October 2020

Oral HPV16 Prevalence in Oral Potentially Malignant Disorders and Oral Cavity Cancers.

Biomolecules 2020 02 3;10(2). Epub 2020 Feb 3.

Saliva & Liquid Biopsy Translational Research Team, The School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology and the Translational Research Institute, Queensland, Brisbane QLD 4059, Australia.

The role of human papillomavirus type 16 (HPV16) in oral potentially malignant disorders (OPMD) and oral cavity carcinoma (OC) is still under debate. We investigated HPV16 prevalence in unstimulated saliva, oral rinse samples, oral swabs and tumour biopsies collected from OPMD ( = 83) and OC ( = 106) patients. HPV16 genotype, viral load, physical status (episomal vs. integrated) and tumour p16INK4a expression were determined. Oral HPV16 prevalence was higher in OC than in OPMD, but this difference was not statistically significant (7.5% (8/106) versus 3.6% (3/83), odds ratio (OR): 2.18, 95% confidence interval (CI): 0.56, 8.48, = 0.26). There was a significant association ( < 0.05) between oral HPV16 infection and heavy tobacco consumption. Real-time PCR results indicated that no integration events occurred in either OPMD or OC cases based on the HPV16 E2/E6 ratio. HPV16 positive OPMD and OC patients had similar HPV16 E2 and E6 viral loads. The inter-rater agreement between tumour p16INK4a expression and oral HPV16 infection was considered as fair (k = 0.361) for OC. Our data suggest that the involvement of HPV16 in oral carcinogenesis is limited.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/biom10020223DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7072384PMC
February 2020

Unlocking the Potential of Saliva-Based Test to Detect HPV-16-Driven Oropharyngeal Cancer.

Cancers (Basel) 2019 Apr 3;11(4). Epub 2019 Apr 3.

The School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology and the Translational Research Institute, Queensland 4059, Australia.

The incidence of human papillomavirus (HPV)-positive oropharyngeal cancer (OPC) is rising in high-income countries, including Australia. Increasing evidence suggests that accurate HPV testing is pivotal for clinical decision making and treatment planning in these patients. Recently, the eighth edition of the American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) tumor-node-metastasis (TNM) staging system for OPC (based on the p16INK4a (p16) status) was proposed and has been implemented. However, the applicability of this new staging system is still far from clear. In our study, = 127 OPC patients from Queensland, Australia were recruited, and the tumor p16 expression in these patients was examined using immunohistochemical (IHC) analysis. HPV-16 genotyping, viral load, and physical status (episomal versus integrated) in the saliva samples of OPC patients were determined using the qPCR method. A good inter-rater agreement ( = 0.612) was found between tumor p16 expression and oral HPV-16 infection in OPC. Importantly, according to the eighth edition staging system, HPV-16 DNA viral load (>10 copies/50 ng) was significantly associated with the advanced stages of OPC. In concordance with previous studies, a mixed HPV-16 form (partially or fully integrated) was predominately found in OPC patients. Taken together, our data support HPV-16 detection in saliva as a screening biomarker to identify people within the community who are at risk of developing OPC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/cancers11040473DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6521163PMC
April 2019

Adenovirus based HPV L2 vaccine induces broad cross-reactive humoral immune responses.

Vaccine 2018 07 18;36(30):4462-4470. Epub 2018 Jun 18.

Janssen Vaccines and Prevention, Pharmaceutical Companies of Johnson and Johnson, Leiden, The Netherlands. Electronic address:

Oncogenic high-risk human papillomavirus (HPV) infections cause a substantial number of genital and non-genital cancers worldwide. Approximately 70% of all cervical cancers are caused by the high-risk HPV16 and 18 types. The remaining 30% can be attributed to twelve other high-risk HPV-types. Highly efficacious 2-valent, 4-valent and 9-valent L1 protein based prophylactic HPV vaccines are available however with limited cross-protection. To further increase the coverage, development of a multivalent cross-protective HPV vaccine is currently focused on the conserved N-terminus of HPV's L2 protein. We have developed a vaccine candidate based on the rare human adenovirus type 35 (HAdV35) vector that displays a concatemer of L2 protein epitopes from four different HPV-types via protein IX (pIX). A mix of two heterologous HAdV35 pIX-L2 display vectors present highly conserved linear epitopes of nine HPV-types. Each HAdV35 pIX-L2 display vector exhibits a good manufacturability profile. HAdV35 pIX-L2 display vaccine vectors were immunogenic and induced neutralizing antibodies against HPV-types included in the vaccine and cross-neutralizing antibodies against distant a HPV-type not included in the vaccine in mice. The HAdV35 pIX-L2 display vectors offer an opportunity for a multivalent HAdV-based prophylactic HPV vaccine.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.vaccine.2018.06.024DOI Listing
July 2018

Adenovirus vector-based prime-boost vaccination via heterologous routes induces cervicovaginal CD8 T cell responses against HPV16 oncoproteins.

Int J Cancer 2018 04 1;142(7):1467-1479. Epub 2017 Dec 1.

Laboratory of Cellular Oncology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.

Recent advances in immunotherapy against cancer underscore the importance of T lymphocytes and tumor microenvironment, but few vaccines targeting cancer have been approved likely due in part to the dearth of common tumor antigens, insufficient immunogenicity and the evolution of immune evasion mechanisms during the progression to malignancy. Human papillomaviruses (HPVs) are the primary etiologic agents of cervical cancer and progression from persistent HPV-infection to cervical intraepithelial lesions and eventually cancer requires persistent expression of the oncoproteins E6 and E7. This offers the opportunity to specifically target these virus-specific antigens for vaccine-induced clearance of infected cells before cancers develop. Here we have evaluated the immunogenicity of Adenovirus Types 26 and 35 derived vectors expressing a fusion of HPV16 E6 and E7 oncoproteins after intramuscular (IM) and/or intravaginal (Ivag) immunization in mice. The adenovirus vectors were shown to transduce an intact cervicovaginal epithelium. IM prime followed by Ivag boost maximized the induction and trafficking of HPV-specific CD8 T cells producing IFN-γ and TNF-α to the cervicovaginal tract. Importantly, the cervicovaginal CD8 T cells expressed CD69 and CD103; hallmarks of intraepithelial tissue-resident memory CD8 T cells. This prime-boost strategy targeting heterologous locations also induced circulating HPV-specific CD8 T cell responses. Our study prompts further evaluation of Ivag immunization with adenoviral vectors expressing modified E6 and E7 antigens for therapeutic vaccination against persistent HPV infection and cervical intraepithelial neoplasia.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ijc.31166DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5805635PMC
April 2018

Development of a replication-deficient adenoviral vector-based vaccine candidate for the interception of HPV16- and HPV18-induced infections and disease.

Int J Cancer 2017 07 24;141(2):393-404. Epub 2017 Apr 24.

Janssen Vaccines and Preventions BV, CA, Leiden, The Netherlands.

High-risk Human papilloma virus (HPV) types are the causative agents of cervical cancer and several other anogenital malignancies. The viral proteins expressed in the (pre)malignant cells are considered ideal targets for immunological intervention. Many approaches have been evaluated for this purpose, mostly aiming at the induction of HPV16 E7- and/or E6-specific cellular immunogenicity. As clinical success has so far been limited, novel approaches are required. We describe the development and pre-clinical testing of a vaccine candidate consisting of replication-deficient adenovirus type 26 and 35 based vectors for the interception of HPV16- and HPV18-related disease. We developed HPV16- and HPV18-specific antigens consisting of fusion proteins of E2, E6 and E7. The vaccine will be suitable for every disease stage, from incident and persistent infections where E2 is predominantly expressed up to late stages where E6 and E7 expression are upregulated. Importantly E6 and E7 are present as reordered fragments to abrogate the transforming activity of these two proteins. Loss of transforming activity was demonstrated in different in vitro models. Robust T-cell immunogenicity was induced upon immunization of mice with the vaccine candidate. Finally, the developed vaccine vectors showed considerable therapeutic efficacy in the TC-1 mouse model. The absence of transforming activity of the antigens and the favorable immunogenicity profile of the adenovirus based vectors along with the fact that these vectors can be readily produced on a large scale makes this approach attractive for clinical evaluation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ijc.30679DOI Listing
July 2017

Astrocytes are central in the pathomechanisms of vanishing white matter.

J Clin Invest 2016 Apr 14;126(4):1512-24. Epub 2016 Mar 14.

Vanishing white matter (VWM) is a fatal leukodystrophy that is caused by mutations in genes encoding subunits of eukaryotic translation initiation factor 2B (eIF2B). Disease onset and severity are codetermined by genotype. White matter astrocytes and oligodendrocytes are almost exclusively affected; however, the mechanisms of VWM development remain unclear. Here, we used VWM mouse models, patients' tissue, and cell cultures to investigate whether astrocytes or oligodendrocytes are the primary affected cell type. We generated 2 mouse models with mutations (Eif2b5Arg191His/Arg191His and Eif2b4Arg484Trp/Arg484Trp) that cause severe VWM in humans and then crossed these strains to develop mice with various mutation combinations. Phenotypic severity was highly variable and dependent on genotype, reproducing the clinical spectrum of human VWM. In all mutant strains, impaired maturation of white matter astrocytes preceded onset and paralleled disease severity and progression. Bergmann glia and retinal Müller cells, nonforebrain astrocytes that have not been associated with VWM, were also affected, and involvement of these cells was confirmed in VWM patients. In coculture, VWM astrocytes secreted factors that inhibited oligodendrocyte maturation, whereas WT astrocytes allowed normal maturation of VWM oligodendrocytes. These studies demonstrate that astrocytes are central in VWM pathomechanisms and constitute potential therapeutic targets. Importantly, astrocytes should also be considered in the pathophysiology of other white matter disorders.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1172/JCI83908DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4811153PMC
April 2016

Mice with megalencephalic leukoencephalopathy with cysts: a developmental angle.

Ann Neurol 2015 Jan 4;77(1):114-31. Epub 2014 Dec 4.

Department of Pediatrics/Child Neurology, Neuroscience Campus Amsterdam, VU University Medical Center; Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University.

Objective: Megalencephalic leukoencephalopathy with cysts (MLC) is a genetic disease characterized by infantile onset white matter edema and delayed onset neurological deterioration. Loss of MLC1 function causes MLC. MLC1 is involved in ion-water homeostasis, but its exact role is unknown. We generated Mlc1-null mice for further studies.

Methods: We investigated which brain cell types express MLC1, compared developmental expression in mice and men, and studied the consequences of loss of MLC1 in Mlc1-null mice.

Results: Like humans, mice expressed MLC1 only in astrocytes, especially those facing fluid-brain barriers. In mice, MLC1 expression increased until 3 weeks and then stabilized. In humans, MLC1 expression was highest in the first year, decreased, and stabilized from approximately 5 years. Mlc1-null mice had early onset megalencephaly and increased brain water content. From 3 weeks, abnormal astrocytes were present with swollen processes abutting fluid-brain barriers. From 3 months, widespread white matter vacuolization with intramyelinic edema developed. Mlc1-null astrocytes showed slowed regulatory volume decrease and reduced volume-regulated anion currents, which increased upon MLC1 re-expression. Mlc1-null astrocytes showed reduced expression of adhesion molecule GlialCAM and chloride channel ClC-2, but no substantial changes in other known MLC1-interacting proteins.

Interpretation: Mlc1-null mice replicate early stages of the human disease with early onset intramyelinic edema. The cellular functional defects, described for human MLC, were confirmed. The earliest change was astrocytic swelling, substantiating that in MLC the primary defect is in volume regulation by astrocytes. MLC1 expression affects expression of GlialCAM and ClC-2. Abnormal interplay between these proteins is part of the pathomechanisms of MLC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ana.24307DOI Listing
January 2015

Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation: clinical and genetic characterization and target for therapy.

Brain 2014 Apr 24;137(Pt 4):1019-29. Epub 2014 Feb 24.

1 Department of Child Neurology, VU University Medical Centre, Neuroscience Campus, Amsterdam, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.

Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation is a disorder caused by recessive mutations in the gene DARS2, which encodes mitochondrial aspartyl-tRNA synthetase. Recent observations indicate that the phenotypic range of the disease is much wider than initially thought. Currently, no treatment is available. The aims of our study were (i) to explore a possible genotype-phenotype correlation; and (ii) to identify potential therapeutic agents that modulate the splice site mutations in intron 2 of DARS2, present in almost all patients. A cross-sectional observational study was performed in 78 patients with two DARS2 mutations in the Amsterdam and Helsinki databases up to December 2012. Clinical information was collected via questionnaires. An inventory was made of the DARS2 mutations in these patients and those previously published. An assay was developed to assess mitochondrial aspartyl-tRNA synthetase enzyme activity in cells. Using a fluorescence reporter system we screened for drugs that modulate DARS2 splicing. Clinical information of 66 patients was obtained. The clinical severity varied from infantile onset, rapidly fatal disease to adult onset, slow and mild disease. The most common phenotype was characterized by childhood onset and slow neurological deterioration. Full wheelchair dependency was rare and usually began in adulthood. In total, 60 different DARS2 mutations were identified, 13 of which have not been reported before. Except for 4 of 42 cases published by others, all patients were compound heterozygous. Ninety-four per cent of the patients had a splice site mutation in intron 2. The groups of patients sharing the same two mutations were too small for formal assessment of genotype-phenotype correlation. However, some combinations of mutations were consistently associated with a mild phenotype. The mitochondrial aspartyl-tRNA synthetase activity was strongly reduced in patient cells. Among the compounds screened, cantharidin was identified as the most potent modulator of DARS2 splicing. In conclusion, the phenotypic spectrum of leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation is wide, but most often the disease has a relatively slow and mild course. The available evidence suggests that the genotype influences the phenotype, but because of the high number of private mutations, larger numbers of patients are necessary to confirm this. The activity of mitochondrial aspartyl-tRNA synthetase is significantly reduced in patient cells. A compound screen established a 'proof of principle' that the splice site mutation can be influenced. This finding is promising for future therapeutic strategies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/brain/awu026DOI Listing
April 2014

Released selective pressure on a structural domain gives new insights on the functional relaxation of mitochondrial aspartyl-tRNA synthetase.

Biochimie 2014 May 8;100:18-26. Epub 2013 Oct 8.

Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, IBMC - 15 rue René Descartes, F-67084 Strasbourg Cedex, France. Electronic address:

Mammalian mitochondrial aminoacyl-tRNA synthetases are nuclear-encoded enzymes that are essential for mitochondrial protein synthesis. Due to an endosymbiotic origin of the mitochondria, many of them share structural domains with homologous bacterial enzymes of same specificity. This is also the case for human mitochondrial aspartyl-tRNA synthetase (AspRS) that shares the so-called bacterial insertion domain with bacterial homologs. The function of this domain in the mitochondrial proteins is unclear. Here, we show by bioinformatic analyses that the sequences coding for the bacterial insertion domain are less conserved in opisthokont and protist than in bacteria and viridiplantae. The divergence suggests a loss of evolutionary pressure on this domain for non-plant mitochondrial AspRSs. This discovery is further connected with the herein described occurrence of alternatively spliced transcripts of the mRNAs coding for some mammalian mitochondrial AspRSs. Interestingly, the spliced transcripts alternately lack one of the four exons that code for the bacterial insertion domain. Although we showed that the human alternative transcript is present in all tested tissues; co-exists with the full-length form, possesses 5'- and 3'-UTRs, a poly-A tail and is bound to polysomes, we were unable to detect the corresponding protein. The relaxed selective pressure combined with the occurrence of alternative splicing, involving a single structural sub-domain, favors the hypothesis of the loss of function of this domain for AspRSs of mitochondrial location. This evolutionary divergence is in line with other characteristics, established for the human mt-AspRS, that indicate a functional relaxation of non-viridiplantae mt-AspRSs when compared to bacterial and plant ones, despite their common ancestry.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.biochi.2013.09.027DOI Listing
May 2014

A yeast purification system for human translation initiation factors eIF2 and eIF2Bε and their use in the diagnosis of CACH/VWM disease.

PLoS One 2013 15;8(1):e53958. Epub 2013 Jan 15.

Faculty of Life Sciences, The University of Manchester, Manchester, United Kingdom.

Recessive inherited mutations in any of five subunits of the general protein synthesis factor eIF2B are responsible for a white mater neurodegenerative disease with a large clinical spectrum. The classical form is called Childhood Ataxia with CNS hypomyelination (CACH) or Vanishing White Matter Leukoencephalopathy (VWM). eIF2B-related disorders affect glial cells, despite the fact that eIF2B is a ubiquitous protein that functions as a guanine-nucleotide exchange factor (GEF) for its partner protein eIF2 in the translation initiation process in all eukaryotic cells. Decreased eIF2B activity measured by a GEF assay in patients' immortalised lymphocytic cells provides a biochemical diagnostic assay but is limited by the availability of eIF2 protein, which is classically purified from a mammalian cell source by column chromatography. Here we describe the generation of a recombinant expression system to produce purified human eIF2 from yeast cells. We demonstrate that human eIF2 can function in yeast cells in place of the equivalent yeast factor. We purify human eIF2 and the C-terminal domain of human eIF2Bε using affinity chromatography from engineered yeast cells and find that both function in a GEF assay: the first demonstration that this human eIF2Bε domain has GEF function. We show that CACH/VWM mutations within this domain reduce its activity. Finally we demonstrate that the recombinant eIF2 functions similarly to eIF2 purified from rat liver in GEF assays with CACH/VWM eIF2B-mutated patient derived lymphocytic cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0053958PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3545922PMC
June 2013

Pathogenic mutations causing LBSL affect mitochondrial aspartyl-tRNA synthetase in diverse ways.

Biochem J 2013 Mar;450(2):345-50

Department of Child Neurology, VU University Medical Center, De Boelalaan 1117, 1081 HV Amsterdam, The Netherlands.

The autosomal recessive white matter disorder LBSL (leukoencephalopathy with brain stem and spinal cord involvement and lactate elevation) is caused by mutations in DARS2, coding for mtAspRS (mitochondrial aspartyl-tRNA synthetase). Generally, patients are compound heterozygous for mutations in DARS2. Many different mutations have been identified in patients, including several missense mutations. In the present study, we have examined the effects of missense mutations found in LBSL patients on the expression, enzyme activity, localization and dimerization of mtAspRS, which is important for understanding the cellular defect underlying the pathogenesis of the disease. Nine different missense mutations were analysed and were shown to have various effects on mtAspRS properties. Several mutations have a direct effect on the catalytic activity of the enzyme; others have an effect on protein expression or dimerization. Most mutations have a clear impact on at least one of the properties of mtAspRS studied, probably resulting in a small contribution of the missense variants to the mitochondrial aspartylation activity in the cell.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1042/BJ20121564DOI Listing
March 2013

Leukoencephalopathy with brain stem and spinal cord involvement and lactate elevation is associated with cell-type-dependent splicing of mtAspRS mRNA.

Biochem J 2012 Feb;441(3):955-62

Department of Child Neurology, VU University Medical Center, Amsterdam, The Netherlands.

LBSL (leukoencephalopathy with brain stem and spinal cord involvement and lactate elevation) is an autosomal recessive white matter disorder with slowly progressive cerebellar ataxia, spasticity and dorsal column dysfunction. Magnetic resonance imaging shows characteristic abnormalities in the cerebral white matter and specific brain stem and spinal cord tracts. LBSL is caused by mutations in the gene DARS2, which encodes mtAspRS (mitochondrial aspartyl-tRNA synthetase). The selective involvement of specific white matter tracts in LBSL is striking since this protein is ubiquitously expressed. Almost all LBSL patients have one mutation in intron 2 of DARS2, affecting the splicing of the third exon. Using a splicing reporter construct, we find cell-type-specific differences in the sensitivity to these mutations: the mutations have a larger effect on exon 3 exclusion in neural cell lines, especially neuronal cell lines, than in non-neural cell lines. Furthermore, correct inclusion of exon 3 in the normal mtAspRS mRNA occurs less efficiently in neural cells than in other cell types, and this effect is again most pronounced in neuronal cells. The combined result of these two effects may explain the selective vulnerability of specific white matter tracts in LBSL patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1042/BJ20110795DOI Listing
February 2012

Megalencephalic leucoencephalopathy with cysts: defect in chloride currents and cell volume regulation.

Brain 2011 Nov 17;134(Pt 11):3342-54. Epub 2011 Oct 17.

Department of Child Neurology, VU University Medical Center, 1081 HV Amsterdam, The Netherlands.

Megalencephalic leucoencephalopathy with subcortical cysts is a genetic brain disorder with onset in early childhood. Affected infants develop macrocephaly within the first year of life, after several years followed by slowly progressive, incapacitating cerebellar ataxia and spasticity. From early on, magnetic resonance imaging shows diffuse signal abnormality and swelling of the cerebral white matter, with evidence of highly increased white matter water content. In most patients, the disease is caused by mutations in the gene MLC1, which encodes a plasma membrane protein almost exclusively expressed in brain and at lower levels in leucocytes. Within the brain, MLC1 is mainly located in astrocyte-astrocyte junctions adjacent to the blood-brain and cereborspinal fluid-brain barriers. Thus far, the function of MLC1 has remained unknown. We tested the hypothesis that MLC1 mutations cause a defect in ion currents involved in water and ion homeostasis, resulting in cerebral white matter oedema. Using whole-cell patch clamp studies we demonstrated an association between MLC1 expression and anion channel activity in different cell types, most importantly astrocytes. The currents were absent in chloride-free medium and in cells with disease-causing MLC1 mutations. MLC1-dependent currents were greatly enhanced by hypotonic pretreatment causing cell swelling, while ion channel blockers, including Tamoxifen, abolished the currents. Down regulation of endogenous MLC1 expression in astrocytes by small interfering RNA greatly reduced the activity of this channel, which was rescued by overexpression of normal MLC1. The current-voltage relationship and the pharmacological profiles of the currents indicated that the channel activated by MLC1 expression is a volume-regulated anion channel. Such channels are involved in regulatory volume decrease. We showed that regulatory volume decrease was hampered in lymphoblasts from patients with megalencephalic leucoencephalopathy. A similar trend was observed in astrocytes with decreased MLC1 expression; this effect was rescued by overexpression of normal MLC1. In the present study, we show that absence or mutations of the MLC1 protein negatively impact both volume-regulated anion channel activity and regulatory volume decrease, indicating that megalencephalic leucoencephalopathy is caused by a disturbance of cell volume regulation mediated by chloride transport.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/brain/awr255DOI Listing
November 2011

Molecular mechanisms of MLC1 and GLIALCAM mutations in megalencephalic leukoencephalopathy with subcortical cysts.

Hum Mol Genet 2011 Aug 30;20(16):3266-77. Epub 2011 May 30.

Sección de Fisiología, Idibell-Hospital Universitari de Bellvitge, Hospitalet de LLobregat, Universitat de Barcelona, Barcelona, Spain.

Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare leukodystrophy caused by mutations in MLC1 or GLIALCAM. The GLIALCAM gene product functions as an MLC1 beta-subunit. We aim to further clarify the molecular mechanisms of MLC caused by mutations in MLC1 or GLIALCAM. For this purpose, we analyzed a human post-mortem brain obtained from an MLC patient, who was homozygous for a missense mutation (S69L) in MLC1. We showed that this mutation affects the stability of MLC1 in vitro and reduces MLC1 protein levels in the brain to almost undetectable. However, the amount of GlialCAM and its localization were nearly unaffected, indicating that MLC1 is not necessary for GlialCAM expression or targeting. These findings were supported by experiments in primary astrocytes and in heterologous cells. In addition, we demonstrated that MLC1 and GlialCAM form homo- and hetero-complexes and that MLC-causing mutations in GLIALCAM mainly reduce the formation of GlialCAM homo-complexes, leading to a defect in the trafficking of GlialCAM alone to cell junctions. GLIALCAM mutations also affect the trafficking of its associated molecule MLC1, explaining why GLIALCAM and MLC1 mutations lead to the same disease: MLC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/hmg/ddr238DOI Listing
August 2011

Not all cystic leukoencephalopathies are "vanishing white matter".

Mol Genet Metab 2011 Aug 5;103(4):413; author reply 414. Epub 2011 May 5.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ymgme.2011.04.011DOI Listing
August 2011

Severity of vanishing white matter disease does not correlate with deficits in eIF2B activity or the integrity of eIF2B complexes.

Hum Mutat 2011 Sep;32(9):1036-45

Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, People's Republic of China.

Autosomal recessive mutations in eukaryotic initiation factor 2B (eIF2B) cause leukoencephalopathy vanishing white matter with a wide clinical spectrum. eIF2B comprises five subunits (α-ε; genes EIF2B1, 2, 3, 4 and 5) and is the guanine nucleotide-exchange factor (GEF) for eIF2. It plays a key role in protein synthesis. Here, we have studied the functional effects of selected VWM mutations in EIF2B2-5 by coexpressing mutated and wild-type subunits in human cells. The observed functional effects are very diverse, including defects in eIF2B complex integrity; binding to the regulatory α-subunit; substrate binding; and GEF activity. Activity data for recombinant eIF2B complexes agree closely with those for patient-derived cells with the same mutations. Some mutations do not affect these parameters even though they cause severe disease. These findings are important for three reasons; they demonstrate that measuring eIF2B activity in patients' cells has limited value as a diagnostic test; they imply that severe disease can result from alterations in eIF2B function other than defects in complex integrity, substrate binding or GEF activity, and last, the diversity of functional effects of VWM mutations implies that seeking agents to manage or treat VWM should focus on downstream effectors of eIF2B, not restoring eIF2B activity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/humu.21535DOI Listing
September 2011

Leukoencephalopathy with brain stem and spinal cord involvement and high lactate: a genetically proven case without elevated white matter lactate.

J Child Neurol 2011 Jun 14;26(6):773-6. Epub 2011 Apr 14.

Division of Neurology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India.

A 17-year-old Indian boy with gradually progressive ataxia with onset at 12 years of age is described. Magnetic resonance imaging (MRI) of the brain revealed extensive, inhomogeneous signal abnormalities in the cerebral white matter, with involvement of selected tracts in the brain stem and spinal cord. The imaging findings were characteristic of leukoencephalopathy with brain stem and spinal cord involvement and high lactate, a recently described leukodystrophy. Interestingly, magnetic resonance spectroscopy of the abnormal white matter did not reveal elevated lactate. The patient was compound heterozygous for 2 new mutations in DARS2, genetically confirming the diagnosis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/0883073810390695DOI Listing
June 2011

Knockdown of MLC1 in primary astrocytes causes cell vacuolation: a MLC disease cell model.

Neurobiol Dis 2011 Jul 3;43(1):228-38. Epub 2011 Apr 3.

Sección de Fisiología, Departamento de Ciencias Fisiológicas II, Universidad de Barcelona, Spain.

Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare type of leukodystrophy, in the majority of cases caused by mutations in the MLC1 gene. MRI from MLC patients shows diffuse cerebral white matter signal abnormality and swelling, with evidence of increased water content. Histopathology in a MLC patient shows vacuolation of myelin, which causes the cerebral white matter swelling. MLC1 protein is expressed in astrocytic processes that are part of blood- and cerebrospinal fluid-brain barriers. We aimed to create an astrocyte cell model of MLC disease. The characterization of rat astrocyte cultures revealed MLC1 localization in cell-cell contacts, which contains other proteins described typically in tight and adherent junctions. MLC1 localization in these contacts was demonstrated to depend on the actin cytoskeleton; it was not altered when disrupting the microtubule or the GFAP networks. In human tissues, MLC1 and the protein Zonula Occludens 1 (ZO-1), which is linked to the actin cytoskeleton, co-localized by EM immunostaining and were specifically co-immunoprecipitated. To create an MLC cell model, knockdown of MLC1 in primary astrocytes was performed. Reduction of MLC1 expression resulted in the appearance of intracellular vacuoles. This vacuolation was reversed by the co-expression of human MLC1. Re-examination of a human brain biopsy from an MLC patient revealed that vacuoles were also consistently present in astrocytic processes. Thus, vacuolation of astrocytes is also a hallmark of MLC disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.nbd.2011.03.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3885813PMC
July 2011

Mutant GlialCAM causes megalencephalic leukoencephalopathy with subcortical cysts, benign familial macrocephaly, and macrocephaly with retardation and autism.

Am J Hum Genet 2011 Apr 17;88(4):422-32. Epub 2011 Mar 17.

Sección de Fisiología, Departamento de Ciencias Fisiologicas II, University of Barcelona, 08907 Barcelona, Spain.

Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a leukodystrophy characterized by early-onset macrocephaly and delayed-onset neurological deterioration. Recessive MLC1 mutations are observed in 75% of patients with MLC. Genetic-linkage studies failed to identify another gene. We recently showed that some patients without MLC1 mutations display the classical phenotype; others improve or become normal but retain macrocephaly. To find another MLC-related gene, we used quantitative proteomic analysis of affinity-purified MLC1 as an alternative approach and found that GlialCAM, an IgG-like cell adhesion molecule that is also called HepaCAM and is encoded by HEPACAM, is a direct MLC1-binding partner. Analysis of 40 MLC patients without MLC1 mutations revealed multiple different HEPACAM mutations. Ten patients with the classical, deteriorating phenotype had two mutations, and 18 patients with the improving phenotype had one mutation. Most parents with a single mutation had macrocephaly, indicating dominant inheritance. In some families with dominant HEPACAM mutations, the clinical picture and magnetic resonance imaging normalized, indicating that HEPACAM mutations can cause benign familial macrocephaly. In other families with dominant HEPACAM mutations, patients had macrocephaly and mental retardation with or without autism. Further experiments demonstrated that GlialCAM and MLC1 both localize in axons and colocalize in junctions between astrocytes. GlialCAM is additionally located in myelin. Mutant GlialCAM disrupts the localization of MLC1-GlialCAM complexes in astrocytic junctions in a manner reflecting the mode of inheritance. In conclusion, GlialCAM is required for proper localization of MLC1. HEPACAM is the second gene found to be mutated in MLC. Dominant HEPACAM mutations can cause either macrocephaly and mental retardation with or without autism or benign familial macrocephaly.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ajhg.2011.02.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3071909PMC
April 2011

Leukoencephalopathy with brain stem and spinal cord involvement and lactate elevation in the first Polish patient.

Brain Dev 2011 Oct 28;33(9):713-7. Epub 2011 Jan 28.

Department of Child Neurology, Institute of Mother and Child, Warsaw, Poland.

Leukoencephalopathy with brain stem and spinal cord involvement and elevated white matter lactate (LBSL) is a very rare autosomal recessive mitochondrial disorder. Clinically patients have slowly progressive ataxia, pyramidal syndrome and dorsal column dysfunction. The disease is defined on the basis of characteristic abnormalities observed on magnetic resonance imaging such as inhomogeneous, spotty involvement of the cerebral white matter, selective involvement of brain stem and spinal cord tracts as well as lactate elevation in the affected white matter on spectroscopy. We present the first identified Polish patient suffering from LBSL confirmed molecularly.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.braindev.2010.12.005DOI Listing
October 2011

Defective glial maturation in vanishing white matter disease.

J Neuropathol Exp Neurol 2011 Jan;70(1):69-82

Department of Pediatrics/Child Neurology, VU University Medical Center, Amsterdam, the Netherlands.

Vanishing white matter (VWM) disease is a genetic leukoencephalopathy linked to mutations in the eukaryotic translation initiation factor 2B. It is a disease of infants, children, and adults who experience a slowly progressive neurologic deterioration with episodes of rapid clinical worsening triggered by stress and eventually leading to death. Characteristic neuropathologic findings include cystic degeneration of the white matter with scarce reactive gliosis, dysmorphic astrocytes, and paucity of myelin despite an increase in oligodendrocytic density. To assess whether a defective maturation of macroglia may be responsible for the feeble gliosis and lack of myelin, weinvestigated the maturation status of astrocytes and oligodendrocytes in the brains of 8 VWM patients, 4 patients with other white matter disorders and 6 age-matched controls with a combination of immunocytochemistry, histochemistry, scratch-wound assays, Western blot, and quantitative polymerase chain reaction. We observed increased proliferation and a defect in the maturation of VWM astrocytes. They show an anomalous composition of their intermediate filament network with predominance of the δ-isoform of the glial fibrillary acidic protein and an increase in the heat shock protein αB-crystallin, supporting the possibility that a deficiency in astrocyte function may contribute to the loss of white matter in VWM. We also demonstrated a significant increase in numbers of premyelinating oligodendrocyte progenitors in VWM, which may explain the coexistence of oligodendrocytosis and myelin paucity in the patients' white matter.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/NEN.0b013e318203ae74DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4135437PMC
January 2011

A human pathology-related mutation prevents import of an aminoacyl-tRNA synthetase into mitochondria.

Biochem J 2011 Feb;433(3):441-6

Université de Strasbourg, CNRS, IBMC, Strasbourg, France.

Mutations in the nuclear gene coding for the mitochondrial aspartyl-tRNA synthetase, a key enzyme for mitochondrial translation, are correlated with leukoencephalopathy. A Ser⁴⁵ to Gly⁴⁵ mutation is located in the predicted targeting signal of the protein. We demonstrate in the present study, by in vivo and in vitro approaches, that this pathology-related mutation impairs the import process across mitochondrial membranes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1042/BJ20101902DOI Listing
February 2011

Vanishing white matter disease associated with ptosis and myoclonic seizures.

J Child Neurol 2011 Mar 29;26(3):366-8. Epub 2010 Nov 29.

All India Institute of Medical Sciences, New Delhi, India.

A 5-year-old boy who presented with progressive ataxia, neuroregression, and worsening with febrile illnesses is described. He also had myoclonic jerks and ptosis. His elder sister had died of a similar illness. Serial magnetic resonance imaging of the brain demonstrated extensive abnormality of the cerebral white matter with rarefaction and cystic degeneration, suggestive of vanishing white matter disease. The patient was found to be compound heterozygous for 2 new mutations in the gene EIF2B5, confirming the diagnosis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/0883073810381529DOI Listing
March 2011

Leukoencephalopathy with vanishing white matter: a review.

J Neuropathol Exp Neurol 2010 Oct;69(10):987-96

Departments of Pediatrics, VU University Medical Center, Amsterdam, The Netherlands.

Vanishing white matter (VWM) is one of the most prevalent inherited childhood leukoencephalopathies, but this may affect people of all ages, including neonates and adults. It is a progressive disorder clinically dominated by cerebellar ataxia and in which minor stress conditions, such as fever or mild trauma, provoke major episodes of neurologic deterioration. Typical pathological findings include increasing white matter rarefaction and cystic degeneration, oligodendrocytosis with highly characteristic foamy oligodendrocytes, meager astrogliosis with dysmorphic astrocytes, and loss of oligodendrocytes by apoptosis. Vanishing white matter is caused by mutations in any of the genes encoding the 5 subunits of the eukaryotic translation initiation factor 2B (eIF2B), EIF2B1 through EIF2B5. eIF2B is a ubiquitously expressed protein complex that plays a crucial role in regulating the rate of protein synthesis. Vanishing white matter mutations reduce the activity of eIF2B and impair its function to couple protein synthesis to the cellular demands in basal conditions and during stress. Reduced eIF2B activity leads to sustained improper activation of the unfolded protein response, resulting in concomitant expression of proliferation, prosurvival, and proapoptotic downstream effectors. Consequently, VWM cells are constitutively predisposed and hyperreactive to stress. In view of the fact that VWM genes are housekeeping genes, it is surprising that the disease is primarily a leukoencephalopathy. The pathophysiology of selective glial vulnerability in VWM remains poorly understood.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/NEN.0b013e3181f2eafaDOI Listing
October 2010

Two cases with megalencephalic leukoencephalopathy with subcortical cysts and MLC1 mutations in the Turkish population.

Turk J Pediatr 2010 Mar-Apr;52(2):179-83

Division of Child Neurology, Gaziantep Children's Hospital, Gaziantep, Turkey.

Megalencephalic leukoencephalopathy with subcortical cysts is a rare leukodystrophy that is characterized by macrocephaly and a slowly progressive clinical course. It is one of the most commonly reported leukoencephalopathies in Turkey. Mutations in the MLC1 gene are the main cause of the disease. We report two patients with megalencephalic leukoencephalopathy with subcortical cysts with confirmed mutations in the MLC1 gene. The mutation in the second patient was novel. We also review identified mutations in the Turkish population.
View Article and Find Full Text PDF

Download full-text PDF

Source
August 2010