Publications by authors named "Odile Boespflug-Tanguy"

119 Publications

Evaluation of CSF1R-related adult onset leukoencephalopathy with axonal spheroids and pigmented glia diagnostic criteria.

Eur J Neurol 2021 Sep 19. Epub 2021 Sep 19.

Department of Neurology, INM, INSERM, University of Montpellier, Montpellier University Hospital, Montpellier, France.

Background And Purpose: Diagnostic criteria for adult onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) due to colony-stimulating factor 1 receptor (CSF1R) mutation have recently been proposed. Our objective was to assess their accuracy in an independent multicenter cohort.

Methods: We evaluated the sensitivity and specificity of the diagnostic criteria for ALSP (including the "probable" and "possible" definitions) in a national cohort of 22 patients with CSF1R mutation, and 59 patients with an alternative diagnosis of adult onset inherited leukoencephalopathy.

Results: Overall, the sensitivity of the diagnostic criteria for ALSP was 82%, including nine of 22 patients diagnosed as probable and nine of 22 diagnosed as possible. Twenty of the 59 CSF1R mutation-negative leukoencephalopathies fulfilled the diagnostic criteria, leading to a specificity of 66%.

Conclusions: Diagnostic criteria for ALSP have an overall limited sensitivity along with a modest specificity. We suggest that in patients suspected of genetic leukoencephalopathy, a comprehensive magnetic resonance imaging pattern-based approach is warranted, together with white matter gene panel or whole exome sequencing.
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http://dx.doi.org/10.1111/ene.15115DOI Listing
September 2021

Onasemnogene abeparvovec gene therapy for symptomatic infantile-onset spinal muscular atrophy type 1 (STR1VE-EU): an open-label, single-arm, multicentre, phase 3 trial.

Lancet Neurol 2021 10;20(10):832-841

Novartis Gene Therapies, Cambridge, UK.

Background: Spinal muscular atrophy is a rare, autosomal recessive, neuromuscular disease caused by biallelic loss of the survival motor neuron 1 (SMN1) gene, resulting in motor neuron dysfunction. In this STR1VE-EU study, we aimed to evaluate the safety and efficacy of onasemnogene abeparvovec gene replacement therapy in infants with spinal muscular atrophy type 1, using broader eligibility criteria than those used in STR1VE-US.

Methods: STR1VE-EU was a multicentre, single-arm, single-dose, open-label phase 3 trial done at nine sites (hospitals and universities) in Italy (n=4), the UK (n=2), Belgium (n=2), and France (n=1). We enrolled patients younger than 6 months (180 days) with spinal muscular atrophy type 1 and the common biallelic pathogenic SMN1 exon 7-8 deletion or point mutations, and one or two copies of SMN2. Patients received a one-time intravenous infusion of onasemnogene abeparvovec (1·1 × 10 vector genomes [vg]/kg). The outpatient follow-up consisted of assessments once per week starting at day 7 post-infusion for 4 weeks and then once per month until the end of the study (at age 18 months or early termination). The primary outcome was independent sitting for at least 10 s, as defined by the WHO Multicentre Growth Reference Study, at any visit up to the 18 months of age study visit, measured in the intention-to-treat population. Efficacy was compared with the Pediatric Neuromuscular Clinical Research (PNCR) natural history cohort. This trial is registered with ClinicalTrials.gov, NCT03461289 (completed).

Findings: From Aug 16, 2018, to Sept 11, 2020, 41 patients with spinal muscular atrophy were assessed for eligibility. The median age at onasemnogene abeparvovec dosing was 4·1 months (IQR 3·0-5·2). 32 (97%) of 33 patients completed the study and were included in the ITT population (one patient was excluded despite completing the study because of dosing at 181 days). 14 (44%, 97·5% CI 26-100) of 32 patients achieved the primary endpoint of functional independent sitting for at least 10 s at any visit up to the 18 months of age study visit (vs 0 of 23 untreated patients in the PNCR cohort; p<0·0001). 31 (97%, 95% CI 91-100) of 32 patients in the ITT population survived free from permanent ventilatory support at 14 months compared with six (26%, 8-44) of 23 patients in the PNCR natural history cohort (p<0·0001). 32 (97%) of 33 patients had at least one adverse event and six (18%) had adverse events that were considered serious and related to onasemnogene abeparvovec. The most common adverse events were pyrexia (22 [67%] of 33), upper respiratory infection (11 [33%]), and increased alanine aminotransferase (nine [27%]). One death, unrelated to the study drug, occurred from hypoxic-ischaemic brain damage because of a respiratory tract infection during the study.

Interpretation: STR1VE-EU showed efficacy of onasemnogene abeparvovec in infants with symptomatic spinal muscular atrophy type 1. No new safety signals were identified, but further studies are needed to show long-term safety. The benefit-risk profile of onasemnogene abeparvovec seems favourable for this patient population, including those with severe disease at baseline.

Funding: Novartis Gene Therapies.
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http://dx.doi.org/10.1016/S1474-4422(21)00251-9DOI Listing
October 2021

Novel variants causing megalencephalic leukodystrophy in Sudanese families.

J Hum Genet 2021 Sep 10. Epub 2021 Sep 10.

Université de Paris, NeuroDiderot, UMR 1141, INSERM, Paris, France.

Mutations in MLC1 cause megalencephalic leukoencephalopathy with subcortical cysts (MLC), a rare form of leukodystrophy characterized by macrocephaly, epilepsy, spasticity, and slow mental deterioration. Genetic studies of MLC are lacking from many parts of the world, especially in Sub-Saharan Africa. Genomic DNA was extracted for 67 leukodystrophic patients from 43 Sudanese families. Mutations were screened using the NGS panel testing 139 leukodystrophies and leukoencephalopathies causing genes (NextSeq500 Illumina). Five homozygous MLC1 variants were discovered in seven patients from five distinct families, including three consanguineous families from the same region of Sudan. Three variants were missense (c.971 T > G, p.Ile324Ser; c.344 T > C, p.Phe115Ser; and c.881 C > T, p.Pro294Leu), one duplication (c.831_838dupATATCTGT, p.Ser280Tyrfs*8), and one synonymous/splicing-site mutation (c.762 C > T, p.Ser254). The segregation pattern was consistent with autosomal recessive inheritance. The clinical presentation and brain MRI of the seven affected patients were consistent with the diagnosis of MLC1. Due to the high frequency of distinct MLC1 mutations found in our leukodystrophic Sudanese families, we analyzed the coding sequence of MLC1 gene in 124 individuals from the Sudanese genome project in comparison with the 1000-genome project. We found that Sudan has the highest proportion of deleterious variants in MLC1 gene compared with other populations from the 1000-genome project.
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http://dx.doi.org/10.1038/s10038-021-00945-7DOI Listing
September 2021

Hypomyelination and Congenital Cataract: Clinical, Imaging, and Genetic Findings in Three Tunisian Families and Literature Review.

Neuropediatrics 2021 08 30;52(4):302-309. Epub 2021 Jun 30.

Université de Paris, NeuroDiderot, UMR 1141, INSERM, Neuropédiatrie, LEUKOFRANCE, APHP, Hôpital Robert Debré, France.

Hypomyelination and congenital cataract (HCC) is characterized by congenital cataract, progressive neurologic impairment, and diffuse myelin deficiency. This autosomal recessive disorder is caused by homozygous variant in the gene. Five consanguineous Tunisian patients, belonging to three unrelated families, underwent routine blood tests, electroneuromyography, and magnetic resonance imaging of the brain. The direct sequencing of exons was performed for the patients and their relatives. We summarized the 30 previously published HCC cases. All of our patients were carriers of a previously reported c.414 + 1G > T (IVS5 + 1G > T) variant, but the clinical spectrum was variable. Despite the absence of a phenotype-genotype correlation in HCC disease, screening of this splice site variant should be performed in family members at risk.
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http://dx.doi.org/10.1055/s-0041-1728654DOI Listing
August 2021

Opsoclonus-myoclonus in Aicardi-Goutières syndrome.

Dev Med Child Neurol 2021 Dec 21;63(12):1483-1486. Epub 2021 Jun 21.

Starship Paediatric Neurology, Auckland, New Zealand.

Aicardi-Goutières syndrome (AGS) is a rare genetic neuroinflammatory disorder caused by abnormal upregulation of type 1 interferon signalling. Opsoclonus-myoclonus syndrome is a rare autoimmune phenotype demonstrating a disturbance in the humoral immune response mostly seen in the context of paraneoplastic or postinfectious states, although its pathophysiology is incompletely understood. We report the first three children described with AGS demonstrating transient opsoclonus and myoclonus after irritability and/or developmental regression, suggesting a pathological association. We describe the presentation, clinical features, progress, cerebrospinal fluid (CSF) inflammatory markers, electroencephalogram (EEG), and magnetic resonance imaging (MRI) findings in these children. Two patients had developmental regression but demonstrated a positive response to JAK1/2 inhibition clinically and on serial examination of CSF inflammatory markers. These findings suggest that AGS should be considered in children presenting with opsoclonus-myoclonus, and that the association between AGS and opsoclonus-myoclonus further supports the role of immune dysregulation as causal in the rare neurological phenomenon opsoclonus and myoclonus. What this paper adds There is a phenotypic association between opsoclonus-myoclonus syndrome and Aicardi-Goutières syndrome. There is clinical evidence of immune dysregulation in the pathogenesis of opsoclonus and myoclonus.
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http://dx.doi.org/10.1111/dmcn.14969DOI Listing
December 2021

Biallelic mutations in RNF220 cause laminopathies featuring leukodystrophy, ataxia and deafness.

Brain 2021 Nov;144(10):3020-3035

Genetics and Rare Diseases Research Division, Bambino Gesù Children's Hospital, IRCCS, 00146 Rome, Italy.

Leukodystrophies are a heterogeneous group of rare inherited disorders that mostly involve the white matter of the CNS. These conditions are characterized by primary glial cell and myelin sheath pathology of variable aetiology, which causes secondary axonal degeneration, generally emerging with disease progression. Whole exome sequencing performed in five large consanguineous nuclear families allowed us to identify homozygosity for two recurrent missense variants affecting highly conserved residues of RNF220 as the causative event underlying a novel form of leukodystrophy with ataxia and sensorineural deafness. We report these two homozygous missense variants (p.R363Q and p.R365Q) in the ubiquitin E3 ligase RNF220 as the underlying cause of this novel form of leukodystrophy with ataxia and sensorineural deafness that includes fibrotic cardiomyopathy and hepatopathy as associated features in seven consanguineous families. Mass spectrometry analysis identified lamin B1 as the RNF220 binding protein and co-immunoprecipitation experiments demonstrated reduced binding of both RNF220 mutants to lamin B1. We demonstrate that RNF220 silencing in Drosophila melanogaster specifically affects proper localization of lamin Dm0, the fly lamin B1 orthologue, promotes its aggregation and causes a neurodegenerative phenotype, strongly supporting the functional link between RNF220 and lamin B1. Finally, we demonstrate that RNF220 plays a crucial role in the maintenance of nuclear morphology; mutations in primary skin fibroblasts determine nuclear abnormalities such as blebs, herniations and invaginations, which are typically observed in cells of patients affected by laminopathies. Overall, our data identify RNF220 as a gene implicated in leukodystrophy with ataxia and sensorineural deafness and document a critical role of RNF220 in the regulation of nuclear lamina. Our findings provide further evidence on the direct link between nuclear lamina dysfunction and neurodegeneration.
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http://dx.doi.org/10.1093/brain/awab185DOI Listing
November 2021

One-step Reprogramming of Human Fibroblasts into Oligodendrocyte-like Cells by SOX10, OLIG2, and NKX6.2.

Stem Cell Reports 2021 Apr 25;16(4):771-783. Epub 2021 Mar 25.

Institute of Neuropathology, University Hospital Münster, Pottkamp 2, 48149 Münster, Germany. Electronic address:

Limited access to human oligodendrocytes impairs better understanding of oligodendrocyte pathology in myelin diseases. Here, we describe a method to robustly convert human fibroblasts directly into oligodendrocyte-like cells (dc-hiOLs), which allows evaluation of remyelination-promoting compounds and disease modeling. Ectopic expression of SOX10, OLIG2, and NKX6.2 in human fibroblasts results in rapid generation of O4 cells, which further differentiate into MBP mature oligodendrocyte-like cells within 16 days. dc-hiOLs undergo chromatin remodeling to express oligodendrocyte markers, ensheath axons, and nanofibers in vitro, respond to promyelination compound treatment, and recapitulate in vitro oligodendroglial pathologies associated with Pelizaeus-Merzbacher leukodystrophy related to PLP1 mutations. Furthermore, DNA methylome analysis provides evidence that the CpG methylation pattern significantly differs between dc-hiOLs derived from fibroblasts of young and old donors, indicating the maintenance of the source cells' "age." In summary, dc-hiOLs represent a reproducible technology that could contribute to personalized medicine in the field of myelin diseases.
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http://dx.doi.org/10.1016/j.stemcr.2021.03.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8072064PMC
April 2021

Differential Expression of Interferon-Alpha Protein Provides Clues to Tissue Specificity Across Type I Interferonopathies.

J Clin Immunol 2021 04 7;41(3):603-609. Epub 2021 Jan 7.

General Paediatrics- Infectious Diseases and Internal Medicine Department, Robert-Debré Hospital, AP-HP, Nord - Université de Paris, Paris, France.

Whilst upregulation of type I interferon (IFN) signaling is common across the type I interferonopathies (T1Is), central nervous system (CNS) involvement varies between these disorders, the basis of which remains unclear. We collected cerebrospinal fluid (CSF) and serum from patients with Aicardi-Goutières syndrome (AGS), STING-associated vasculopathy with onset in infancy (SAVI), presumed monogenic T1Is (pT1I), childhood systemic lupus erythematosus with neuropsychiatric features (nSLE), non-IFN-related autoinflammation (AI) and non-inflammatory hydrocephalus (as controls). We measured IFN-alpha protein using digital ELISA. Eighty-two and 63 measurements were recorded respectively in CSF and serum of 42 patients and 6 controls. In an intergroup comparison (taking one sample per individual), median CSF IFN-alpha levels were elevated in AGS, SAVI, pT1I, and nSLE compared to AI and controls, with levels highest in AGS compared to all other groups. In AGS, CSF IFN-alpha concentrations were higher than in paired serum samples. In contrast, serum IFN was consistently higher compared to CSF levels in SAVI, pT1I, and nSLE. Whilst IFN-alpha is present in the CSF and serum of all IFN-related diseases studied here, our data suggest the primary sites of IFN production in the monogenic T1I AGS and SAVI are, respectively, the CNS and the periphery. These results inform the diagnosis of, and future therapeutic approaches to, monogenic and multifactorial T1Is.
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http://dx.doi.org/10.1007/s10875-020-00952-xDOI Listing
April 2021

Catatonia in a patient with Aicardi-Goutières syndrome efficiently treated with immunoadsorption.

Schizophr Res 2020 08 19;222:484-486. Epub 2020 Jun 19.

INSERM UMR 1163, Laboratoire de Neurogénétique et Neuroinflammation, Paris, France; Service de Pédiatrie Générale, Maladies Infectieuses et Médecine Interne, Centre de référence des rhumatismes inflammatoires et maladies autoimmunes systémiques rares de l'enfant (RAISE), APHP Robert Debré, Paris, France; Service d'Immunologie-Hématologie et Rhumatologie Pédiatriques, APHP Necker-Enfants Malades, Paris, France.

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http://dx.doi.org/10.1016/j.schres.2020.05.064DOI Listing
August 2020

Foetal onset of EIF2B related disorder in two siblings: cerebellar hypoplasia with absent Bergmann glia and severe hypomyelination.

Acta Neuropathol Commun 2020 04 15;8(1):48. Epub 2020 Apr 15.

Normandie Univ, UNIROUEN, INSERM U1245, Rouen University Hospital, Department of Pathology, F76000, Rouen, France.

Bi-allelic pathogenic variants in genes of the EIF2B family are responsible for Childhood Ataxia with Central nervous system Hypomyelination/Vanishing White Matter disease, a progressive neurodegenerative disorder of the central white matter. Only seven molecularly proven cases with antenatal onset have been reported so far. We report for the first time the neuropathological findings obtained from two foetuses harbouring deleterious variants in the EIF2B5 gene who presented in utero growth retardation and microcephaly with simplified gyral pattern that led to a medical termination of the pregnancy at 27 and 32 weeks of gestation. Neuropathological examination confirmed microcephaly with delayed gyration, periventricular pseudo-cysts and severe cerebellar hypoplasia. Histologically, the cerebellar cortex was immature, the dentate nuclei were fragmented and myelin stains revealed almost no myelination of the infratentorial structures. Bergmann glia was virtually absent associated to a drastic decreased number of mature astrocytes in the cerebellar white matter, multiple nestin-positive immature astrocytes as well as increased numbers of PDGRFα-positive oligodendrocyte precursors. Whole exome sequencing performed in the two foetuses and their parents allowed the identification of two EIF2B5 compound heterozygous variants in the two foetuses: c.468C > G p.Ile156Met and c.1165G > A p.Val389Met, the parents being heterozygous carriers. These variants are absent in the genome Aggregation Database (gnomAD r2.0.2). Contrary to the variant Ile156Met already described in a patient with CACH syndrome, the variant p.Val389Met is novel and predicted to be deleterious using several softwares. Neuropathological findings further expand the phenotypic spectrum of the disease that very likely occurs during early gestation and may manifest from the second half of pregnancy by a severe impairment of cerebral and cerebellar development.
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http://dx.doi.org/10.1186/s40478-020-00929-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7161274PMC
April 2020

Dramatic efficacy of ofatumumab in refractory pediatric-onset AQP4-IgG neuromyelitis optica spectrum disorder.

Neurol Neuroimmunol Neuroinflamm 2020 05 25;7(3). Epub 2020 Feb 25.

From the AP-HP (E.M., C.P.), Pitié-Salpêtrière Hospital, Department of Neurology and Centre de Référence des Maladies Inflammatoires Rares du Cerveau et de la Moelle; Robert Debré Hospital (J.B.F.R., O.B.-T., D.G.), AP-HP Department of Child Neurology; Université de Paris (F.R., O.B.-T., D.G.); Department of Pediatric Neurology (K.D.), National Referral Center for Rare Inflammatory Brain and Spinal Diseases, Hôpitaux Universitaires Paris-Sud, Le Kremlin-Bicetre; Robert Debré Hospital (T.K.), AP-HP Departments of Child Nephrology, Paris; and Service de neurologie (R.M.), sclérose en plaques, pathologies de la myéline et neuro-inflammation, and Centre de Référence des Maladies Inflammatoires Rares du Cerveau et de la Moelle, Hôpital Neurologique Pierre Wertheimer, Hospices Civils de Lyon, Lyon/Bron, France.

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http://dx.doi.org/10.1212/NXI.0000000000000683DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7051209PMC
May 2020

Genetic and phenotypic spectrum associated with IFIH1 gain-of-function.

Hum Mutat 2020 04 14;41(4):837-849. Epub 2020 Jan 14.

Department of Allergy/Immunology, Spectrum Health Helen Devos Children's Hospital, Michigan State University College of Human Medicine, East Lansing, Michigan.

IFIH1 gain-of-function has been reported as a cause of a type I interferonopathy encompassing a spectrum of autoinflammatory phenotypes including Aicardi-Goutières syndrome and Singleton Merten syndrome. Ascertaining patients through a European and North American collaboration, we set out to describe the molecular, clinical and interferon status of a cohort of individuals with pathogenic heterozygous mutations in IFIH1. We identified 74 individuals from 51 families segregating a total of 27 likely pathogenic mutations in IFIH1. Ten adult individuals, 13.5% of all mutation carriers, were clinically asymptomatic (with seven of these aged over 50 years). All mutations were associated with enhanced type I interferon signaling, including six variants (22%) which were predicted as benign according to multiple in silico pathogenicity programs. The identified mutations cluster close to the ATP binding region of the protein. These data confirm variable expression and nonpenetrance as important characteristics of the IFIH1 genotype, a consistent association with enhanced type I interferon signaling, and a common mutational mechanism involving increased RNA binding affinity or decreased efficiency of ATP hydrolysis and filament disassembly rate.
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http://dx.doi.org/10.1002/humu.23975DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7457149PMC
April 2020

KIF1C Variants Are Associated with Hypomyelination, Ataxia, Tremor, and Dystonia in Fraternal Twins.

Tremor Other Hyperkinet Mov (N Y) 2019 17;9. Epub 2019 Jul 17.

Department of Genetics, AP-HP, La Pitié-Salpêtrière University Hospital, Paris, FR.

Background: (Kinesin Family Member 1C) variants have been associated with hereditary spastic paraplegia and spastic ataxia.

Case Report: We report fraternal twins presenting with cerebellar ataxia and dystonic tremor. Their brain MRI showed a hypomyelinating leukoencephalopathy. Whole exome sequencing identified a homozygous variant in both patients.

Discussion: variants can manifest as a complex movement disorder with cerebellar ataxia and dystonic tremor. variants may also cause a hypomyelinating leukoencephalopathy.
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http://dx.doi.org/10.7916/tohm.v0.641DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6692767PMC
January 2020

Expanding the phenotypic spectrum of Allan-Herndon-Dudley syndrome in patients with SLC16A2 mutations.

Dev Med Child Neurol 2019 12 13;61(12):1439-1447. Epub 2019 Aug 13.

Centre de Compétence des Leucodystrophies et Leucoencéphalopathies de Cause Rare, Pôle Femme et Enfant, Hôpital Estaing, Centre Hospitalier Universitaire de Clermont-Ferrand, Clermont-Ferrand, France.

The aim of the study was to redefine the phenotype of Allan-Herndon-Dudley syndrome (AHDS), which is caused by mutations in the SLC16A2 gene that encodes the brain transporter of thyroid hormones. Clinical phenotypes, brain imaging, thyroid hormone profiles, and genetic data were compared to the existing literature. Twenty-four males aged 11 months to 29 years had a mutation in SLC16A2, including 12 novel mutations and five previously described mutations. Sixteen patients presented with profound developmental delay, three had severe intellectual disability with poor language and walking with an aid, four had moderate intellectual disability with language and walking abilities, and one had mild intellectual disability with hypotonia. Overall, eight had learned to walk, all had hypotonia, 17 had spasticity, 18 had dystonia, 12 had choreoathetosis, 19 had hypomyelination, and 10 had brain atrophy. Kyphoscoliosis (n=12), seizures (n=7), and pneumopathies (n=5) were the most severe complications. This study extends the phenotypic spectrum of AHDS to a mild intellectual disability with hypotonia. Developmental delay, hypotonia, hypomyelination, and thyroid hormone profile help to diagnose patients. Clinical course depends on initial severity, with stable acquisition after infancy; this may be adversely affected by neuro-orthopaedic, pulmonary, and epileptic complications. WHAT THIS PAPER ADDS: Mild intellectual disability is associated with SLC16A2 mutations. A thyroid hormone profile with a free T /T ratio higher than 0.75 can help diagnose patients. Patients with SLC16A2 mutations present a broad spectrum of neurological phenotypes that are also observed in other hypomyelinating disorders. Axial hypotonia is a consistent feature of Allan-Herndon-Dudley syndrome and leads to specific complications.
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http://dx.doi.org/10.1111/dmcn.14332DOI Listing
December 2019

Hearing loss in inherited peripheral neuropathies: Molecular diagnosis by NGS in a French series.

Mol Genet Genomic Med 2019 09 8;7(9):e839. Epub 2019 Aug 8.

University of Limoges, MMNP, Limoges, France.

Background: The most common inherited peripheral neuropathy is Charcot-Marie-Tooth disease (CMT), with a prevalence of 1/2500. Other symptoms can be associated to the condition, such as hearing loss. Currently, no global hearing impairment assessment has been determined, and the physiopathology is not well known.

Methods: The aim of the study was to analyze among a French series of 3,412 patients with inherited peripheral neuropathy (IPN), the ones who also suffer from hearing loss, to establish phenotype-genotype correlations. An NGS strategy for IPN one side and nonsyndromic hearing loss (NSHL) on the other side, were performed.

Results: Hearing loss (HL) was present in only 44 patients (1.30%). The clinical data of 27 patients were usable. Demyelinating neuropathy was diagnosed in 15 cases and axonal neuropathy in 12 cases. HL varied from mild to profound. Five cases of auditory neuropathy were noticed. Diagnosis was made for 60% of these patients. Seven novel pathogenic variants were discovered in five different genes: PRPS1; MPZ; SH3TC2; NEFL; and ABHD12. Two patients with PMP22 variant, had also an additional variant in COCH and MYH14 respectively. No pathogenic variant was found at the DFNB1 locus. Genotype-phenotype correlations do exist, especially with SH3TC2, PRPS1, ABHD12, NEFL, and TRPV4.

Conclusion: Involvement of PMP22 is not enough to explain hearing loss in patients suffering from IPN. HL can be due to cochlear impairment and/or auditory nerve dysfunction. HL is certainly underdiagnosed, and should be evaluated in every patient suffering from IPN.
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http://dx.doi.org/10.1002/mgg3.839DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6732311PMC
September 2019

Novel POLR1C mutation in RNA polymerase III-related leukodystrophy with severe myoclonus and dystonia.

Mol Genet Genomic Med 2019 09 31;7(9):e914. Epub 2019 Jul 31.

INSERM UMR1141, Sorbonne Paris Cité, DHU PROTECT, Paris Diderot University, Robert Debré Hospital, Paris, France.

Introduction: RNA polymerase III (Pol III)-related leukodystrophies are a group of autosomal recessive neurodegenerative disorders caused by mutations in POLR3A and POLR3B. Recently a recessive mutation in POLR1C causative of Pol III-related leukodystrophies was identified.

Methods: We report the case of a Tunisian girl of 14 years of age who was referred to our department for evaluation of progressive ataxia that began at the age of 5. Genetic diagnosis was performed by NGS and Sanger analysis. In silico predictions were performed using SIFT, PolyPhen-2, and Mutation Taster.

Results: Neurological examination showed cerebellar and tetrapyramidal syndrome, mixed movement disorders with generalized dystonia and severe myoclonus leading to death at 25 years. Brain MRI scans showed diffuse hypomyelination associated with cerebellar atrophy. It also showed bilateral T2 hypointensity of the ventrolateral thalamus, part of the posterior limb of the internal capsule, the substantia nigra and the subthalamic nucleus. Next generation sequencing leukodystrophy panel including POLR3A and POLR3B was negative. Sanger sequencing of the coding regions of POLR1C revealed a novel homozygous mutation.

Conclusion: The clinical and imaging findings of patients with POLR1C hypomyelinating leukodystrophy are reviewed. Interestingly, severe myoclonic dystonia and T2 hypointensity of the substantia nigra and the subthalamic nucleus are not reported yet and could be helpful for the diagnosis of POLR1C hypomyelinating leukodystrophy.
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http://dx.doi.org/10.1002/mgg3.914DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6732337PMC
September 2019

Deleterious mutations in suggest a novel cause for neuro-ichthyotic syndrome.

NPJ Genom Med 2019 23;4:17. Epub 2019 Jul 23.

3Nutrition Research Institute, University of North Carolina, Chapel Hill, NC USA.

Neuro-ichthyotic syndromes are a group of rare genetic diseases mainly associated with perturbations in lipid metabolism, intracellular vesicle trafficking, or glycoprotein synthesis. Here, we report a patient with a neuro-ichthyotic syndrome associated with deleterious mutations in the (aldehyde dehydrogenase 1 family member L2) gene encoding for mitochondrial 10-formyltetrahydrofolate dehydrogenase. Using fibroblast culture established from the ALDH1L2-deficient patient, we demonstrated that the enzyme loss impaired mitochondrial function affecting both mitochondrial morphology and the pool of metabolites relevant to β-oxidation of fatty acids. Cells lacking the enzyme had distorted mitochondria, accumulated acylcarnitine derivatives and Krebs cycle intermediates, and had lower ATP and increased ADP/AMP indicative of a low energy index. Re-expression of functional ALDH1L2 enzyme in deficient cells restored the mitochondrial morphology and the metabolic profile of fibroblasts from healthy individuals. Our study underscores the role of ALDH1L2 in the maintenance of mitochondrial integrity and energy balance of the cell, and suggests the loss of the enzyme as the cause of neuro-cutaneous disease.
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http://dx.doi.org/10.1038/s41525-019-0092-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6650503PMC
July 2019

Confirmation of Atypical Presentation With Nonprogressive Leukodystrophy in eIF2B-Related Disorders.

Pediatr Neurol 2019 11 1;100:97-99. Epub 2019 Mar 1.

CHU Bordeaux, Service de Génétique Médicale, Bordeaux, France; Laboratoire MRGM, INSERM U1211, Univ. Bordeaux, Bordeaux, France; Centre de référence Neurogénétique, Service de Génétique Médicale, CHU Bordeaux, Bordeaux, France.

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http://dx.doi.org/10.1016/j.pediatrneurol.2019.02.005DOI Listing
November 2019

SLC13A3 variants cause acute reversible leukoencephalopathy and α-ketoglutarate accumulation.

Ann Neurol 2019 03 29;85(3):385-395. Epub 2019 Jan 29.

UMR1141, PROTECT, INSERM, Paris Diderot University, Sorbonne Paris Cité, Paris, France.

Objective: SLC13A3 encodes the plasma membrane Na /dicarboxylate cotransporter 3, which imports inside the cell 4 to 6 carbon dicarboxylates as well as N-acetylaspartate (NAA). SLC13A3 is mainly expressed in kidney, in astrocytes, and in the choroid plexus. We describe two unrelated patients presenting with acute, reversible (and recurrent in one) neurological deterioration during a febrile illness. Both patients exhibited a reversible leukoencephalopathy and a urinary excretion of α-ketoglutarate (αKG) that was markedly increased and persisted over time. In one patient, increased concentrations of cerebrospinal fluid NAA and dicarboxylates (including αKG) were observed. Extensive workup was unsuccessful, and a genetic cause was suspected.

Methods: Whole exome sequencing (WES) was performed. Our teams were connected through GeneMatcher.

Results: WES analysis revealed variants in SLC13A3. A homozygous missense mutation (p.Ala254Asp) was found in the first patient. The second patient was heterozygous for another missense mutation (p.Gly548Ser) and an intronic mutation affecting splicing as demonstrated by reverse transcriptase polymerase chain reaction performed in muscle tissue (c.1016 + 3A > G). Mutations and segregation were confirmed by Sanger sequencing. Functional studies performed on HEK293T cells transiently transfected with wild-type and mutant SLC13A3 indicated that the missense mutations caused a marked reduction in the capacity to transport αKG, succinate, and NAA.

Interpretation: SLC13A3 deficiency causes acute and reversible leukoencephalopathy with marked accumulation of αKG. Urine organic acids (especially αKG and NAA) and SLC13A3 mutations should be screened in patients presenting with unexplained reversible leukoencephalopathy, for which SLC13A3 deficiency is a novel differential diagnosis. ANN NEUROL 2019;85:385-395.
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http://dx.doi.org/10.1002/ana.25412DOI Listing
March 2019

Loss of the sphingolipid desaturase DEGS1 causes hypomyelinating leukodystrophy.

J Clin Invest 2019 03 11;129(3):1240-1256. Epub 2019 Feb 11.

Department of Clinical Genomics and.

Sphingolipid imbalance is the culprit in a variety of neurological diseases, some affecting the myelin sheath. We have used whole-exome sequencing in patients with undetermined leukoencephalopathies to uncover the endoplasmic reticulum lipid desaturase DEGS1 as the causative gene in 19 patients from 13 unrelated families. Shared features among the cases include severe motor arrest, early nystagmus, dystonia, spasticity, and profound failure to thrive. MRI showed hypomyelination, thinning of the corpus callosum, and progressive thalamic and cerebellar atrophy, suggesting a critical role of DEGS1 in myelin development and maintenance. This enzyme converts dihydroceramide (DhCer) into ceramide (Cer) in the final step of the de novo biosynthesis pathway. We detected a marked increase of the substrate DhCer and DhCer/Cer ratios in patients' fibroblasts and muscle. Further, we used a knockdown approach for disease modeling in Danio rerio, followed by a preclinical test with the first-line treatment for multiple sclerosis, fingolimod (FTY720, Gilenya). The enzymatic inhibition of Cer synthase by fingolimod, 1 step prior to DEGS1 in the pathway, reduced the critical DhCer/Cer imbalance and the severe locomotor disability, increasing the number of myelinating oligodendrocytes in a zebrafish model. These proof-of-concept results pave the way to clinical translation.
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http://dx.doi.org/10.1172/JCI123959DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6391109PMC
March 2019

Mutation in causes hypomyelinating leukodystrophy and abnormal ribosomal RNA regulation.

Neurol Genet 2018 Dec 3;4(6):e289. Epub 2018 Dec 3.

INSERM UMR 1141 PROTECT (I.D., P.B., S.S., O.B.-T.), Université Paris Diderot- Sorbonne Paris Cité; INSERM U1212-CNRS UMR 5320 (H.D.-O., M.T.), Université de Bordeaux; Neurologie Pédiatrique et Maladies Métaboliques (K.B., F.R., O.B-.T.), Centre de référence des leucodystrophies et leucoencéphalopathies de cause rare (LEUKOFRANCE), CHU APHP Robert-Debré, Paris, France; LR11IPT05, Biomedical Genomics and Oncogenetics Laboratory (H.J., Y.B.), Institut Pasteur de Tunis; Department of Medical Genetics, UF Molecular Genetics (S.S.), CHU APHP Robert-Debré Paris; Service de Cytogénétique Médicale (E.E.P.), CHU Clermont-Ferrand; Neurologie Pédiatrique (C.C.), Endocrinologie Pédiatrique (C.B.), CHU Hôpital des Enfants, Toulouse; Hôpital Femme Mère Enfant, Neurologie Pédiatrique (A.L.P., C.R.), Hospices Civils de Lyon, Bron; Department of Pediatric Radiology (M.E.-B.), CHU APHP Robert-Debré, Paris, France.

Objective: To identify the genetic cause of hypomyelinating leukodystrophy in 2 consanguineous families.

Methods: Homozygosity mapping combined with whole-exome sequencing of consanguineous families was performed. Mutation consequences were determined by studying the structural change of the protein and by the RNA analysis of patients' fibroblasts.

Results: We identified a biallelic mutation in a gene coding for a Pol III-specific subunit, (c.121C>T/p.Arg41Trp), that cosegregates with the disease in 2 unrelated patients. Patients expressed neurologic and extraneurologic signs found in - and -related leukodystrophies with a peculiar severe digestive dysfunction. The mutation impaired the POLR3K-POLR3B interactions resulting in zebrafish in abnormal gut development. Functional studies in the 2 patients' fibroblasts revealed a severe decrease (60%-80%) in the expression of 5S and 7S ribosomal RNAs in comparison with control.

Conclusions: These analyses underlined the key role of ribosomal RNA regulation in the development and maintenance of the white matter and the cerebellum as already reported for diseases related to genes involved in transfer RNA or translation initiation factors.
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http://dx.doi.org/10.1212/NXG.0000000000000289DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6283457PMC
December 2018

Brain Diffusion Imaging and Tractography to Distinguish Clinical Severity of Human PLP1-Related Disorders.

Dev Neurosci 2018 27;40(4):301-311. Epub 2018 Sep 27.

Service de Neurologie Pédiatrique et Maladies Métaboliques, Centre de référence des leucodystrophies et leucoencéphalopathies de cause rare, CHU-APHP Robert-Debré, Paris, France.

Aims: We performed quantitative diffusion tensor imaging and brain tractography to distinguish clinical severity in a series of 35 patients with hypomyelinating PLP1-related disorders classified using the Motor Developmental Score according to the best motor function acquired before the age of 5 years and the gross motor function measure (GMFM) at the time of magnetic resonance imaging acquisition.

Methods: We calculated fractional anisotropy and diffusivity values in 26 regions of interest and the numbers of fibers and volumes of hemisphere tractograms. Fiber bundles on tractograms were characterized according to 3 criteria: size, direction of main-stream fibers, and connectivity of bundles (extratelencephalic projections, commissural fibers, and intrahemispheric connections).

Results: Age-adjusted multivariate analysis in 3 severity groups revealed increased isotropic diffusion in the superior cerebellar peduncle and grey matter in the most severe group, and larger tractogram volumes and increased numbers of fibers in the least severely affected group. Tractogram patterns showed preserved extratelencephalic projections and a main anterior-posterior aspect of intrahemispheric fibers in most patients, whereas interhemispheric connectivity was variable. The most severely affected and intermediate patients had less intrahemispheric connectivity, with a frequent predominant anterior-posterior direction of main-stream fibers.

Interpretation: Diffusion tensor imaging and tractographic parameters can operate as biomarkers to distinguish clinical severity in PLP1-related disorders and could improve our understanding of hypomyelinating leukodystrophies.
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http://dx.doi.org/10.1159/000492218DOI Listing
March 2019

Mutations in the gene cause severe congenital neutropenia as well as Shwachman-Diamond-like syndrome.

Blood 2018 09 18;132(12):1318-1331. Epub 2018 Jun 18.

Department of Clinical Immunology, Saint-Louis Hospital, AP-HP, Paris, France.

Congenital neutropenias (CNs) are rare heterogeneous genetic disorders, with about 25% of patients without known genetic defects. Using whole-exome sequencing, we identified a heterozygous mutation in the gene, encoding the signal recognition particle (SRP) 54 GTPase protein, in 3 sporadic cases and 1 autosomal dominant family. We subsequently sequenced the gene in 66 probands from the French CN registry. In total, we identified 23 mutated cases (16 sporadic, 7 familial) with 7 distinct germ line mutations including a recurrent in-frame deletion (Thr117del) in 14 cases. In nearly all patients, neutropenia was chronic and profound with promyelocytic maturation arrest, occurring within the first months of life, and required long-term granulocyte colony-stimulating factor therapy with a poor response. Neutropenia was sometimes associated with a severe neurodevelopmental delay (n = 5) and/or an exocrine pancreatic insufficiency requiring enzyme supplementation (n = 3). The SRP54 protein is a key component of the ribonucleoprotein complex that mediates the co-translational targeting of secretory and membrane proteins to the endoplasmic reticulum (ER). We showed that SRP54 was specifically upregulated during the in vitro granulocytic differentiation, and that mutations or knockdown led to a drastically reduced proliferation of granulocytic cells associated with an enhanced P53-dependent apoptosis. Bone marrow examination of -mutated patients revealed a major dysgranulopoiesis and features of cellular ER stress and autophagy that were confirmed using -mutated primary cells and knockdown cells. In conclusion, we characterized a pathological pathway, which represents the second most common cause of CN with maturation arrest in the French CN registry.
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http://dx.doi.org/10.1182/blood-2017-12-820308DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6536700PMC
September 2018

Rapid exhaustion of auditory neural conduction in a prototypical mitochondrial disease, Friedreich ataxia.

Clin Neurophysiol 2018 06 27;129(6):1121-1129. Epub 2018 Mar 27.

Laboratory of Neurosensory Biophysics, UMR INSERM 1107, University Clermont Auvergne, Clermont-Ferrand, France; Centre Jean Perrin, Clermont-Ferrand, France. Electronic address:

Objectives: In patients with Friedreich ataxia (FRDA), mitochondrial failure leads to impaired cellular energetics. Since many FRDA patients have impaired hearing in noise, we investigated the objective consequences on standard auditory brainstem-evoked responses (ABRs).

Methods: In 37 FRDA patients, among whom 34 with abnormal standard ABRs, hearing sensitivity, speech-in-noise intelligibility and otoacoustic emissions were controlled. ABR recordings were split into four consecutive segments of the total time frame used for data collection, thus allowing the dynamics of ABR averaging to be observed.

Results: Most ears showed features of an auditory neuropathy spectrum disorder with flattened ABRs and impaired speech-in-noise intelligibility contrasting with near-normal hearing sensitivity and normal preneural responses. Yet split-ABRs revealed short-lived wave patterns in 26 out of 68 ears with flattened standard ABRs (38%). While averaging went on, the pattern of waves shifted so that interwave latencies increased by 35% on average.

Conclusions: In FRDA, the assumption of stationarity used for extracting standard ABRs is invalid. The preservation of early split-ABRs indicates no short-term dyssynchrony of action potentials. A large decrease in conduction velocity along auditory neurons occurs within seconds, attributed to fast energetic failure.

Significance: This model of metabolic sensory neuropathy warns against exposure of metabolically-impaired patients to sustained auditory stimulation.
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http://dx.doi.org/10.1016/j.clinph.2018.03.005DOI Listing
June 2018

Further delineation of the duplication syndrome phenotype in 59 French male patients, with a particular focus on morphological and neurological features.

J Med Genet 2018 Jun 4;55(6):359-371. Epub 2018 Apr 4.

Service de Génétique Clinique, Hôpital Necker Enfants Malades, APHP, Paris, France.

The Xq28 duplication involving the gene ( duplication) has been mainly described in male patients with severe developmental delay (DD) associated with spasticity, stereotypic movements and recurrent infections. Nevertheless, only a few series have been published. We aimed to better describe the phenotype of this condition, with a focus on morphological and neurological features. Through a national collaborative study, we report a large French series of 59 affected males with interstitial duplication. Most of the patients (93%) shared similar facial features, which evolved with age (midface hypoplasia, narrow and prominent nasal bridge, thick lower lip, large prominent ears), thick hair, livedo of the limbs, tapered fingers, small feet and vasomotor troubles. Early hypotonia and global DD were constant, with 21% of patients unable to walk. In patients able to stand, lower limbs weakness and spasticity led to a singular standing habitus: flexion of the knees, broad-based stance with pseudo-ataxic gait. Scoliosis was frequent (53%), such as divergent strabismus (76%) and hypermetropia (54%), stereotypic movements (89%), without obvious social withdrawal and decreased pain sensitivity (78%). Most of the patients did not develop expressive language, 35% saying few words. Epilepsy was frequent (59%), with a mean onset around 7.4 years of age, and often (62%) drug-resistant. Other medical issues were frequent: constipation (78%), and recurrent infections (89%), mainly lung. We delineate the clinical phenotype of duplication syndrome in a large series of 59 males. Pulmonary hypertension appeared as a cause of early death in these patients, advocating its screening early in life.
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http://dx.doi.org/10.1136/jmedgenet-2017-104956DOI Listing
June 2018

KARS-related diseases: progressive leukoencephalopathy with brainstem and spinal cord calcifications as new phenotype and a review of literature.

Orphanet J Rare Dis 2018 04 4;13(1):45. Epub 2018 Apr 4.

Molecular Neurogenetics, Foundation IRCCS Neurological Institute "C. Besta", Milan, Italy.

Background: KARS encodes lysyl- transfer ribonucleic acid (tRNA) synthetase, which catalyzes the aminoacylation of tRNA-Lys in the cytoplasm and mitochondria. Eleven families/sporadic patients and 16 different mutations in KARS have been reported to date. The associated clinical phenotype is heterogeneous ranging from early onset encephalopathy to isolated peripheral neuropathy or nonsyndromic hearing impairment. Recently additional presentations including leukoencephalopathy as predominant cerebral involvement or cardiomyopathy, isolated or associated with muscular and cerebral involvement, have been reported. A progressive Leukoencephalopathy with brainstem and spinal cord calcifications was previously described in a singleton patient and in two siblings, without the identification of the genetic cause. We reported here about a new severe phenotype associated with biallelic KARS mutations and sharing some common points with the other already reported phenotypes, but with a distinct clinical and neuroimaging picture. Review of KARS mutant patients published to date will be also discussed.

Results: Herein, we report the clinical, biochemical and molecular findings of 2 unreported Italian patients affected by developmental delay, acquired microcephaly, spastic tetraparesis, epilepsy, sensory-neural hypoacusia, visual impairment, microcytic hypochromic anaemia and signs of hepatic dysfunction. MRI pattern in our patients was characterized by progressive diffuse leukoencephalopathy and calcifications extending in cerebral, brainstem and cerebellar white matter, with spinal cord involvement. Genetic analysis performed on these 2 patients and in one subject previously described with similar MRI pattern revealed the presence of biallelic mutations in KARS in all 3 subjects.

Conclusions: With our report we define the molecular basis of the previously described Leukoencephalopathy with Brainstem and Spinal cord Calcification widening the spectrum of KARS related disorders, particularly in childhood onset disease suggestive for mitochondrial impairment. The review of previous cases does not suggest a strict and univocal genotype/phenotype correlation for this highly heterogeneous entity. Moreover, our cases confirm the usefulness of search for common brain and spine MR imaging pattern and of broad genetic screening, in syndromes clinically resembling mitochondrial disorders in spite of normal biochemical assay.
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http://dx.doi.org/10.1186/s13023-018-0788-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5883414PMC
April 2018

Oxidative stress and mitochondrial dynamics malfunction are linked in Pelizaeus-Merzbacher disease.

Brain Pathol 2018 09 26;28(5):611-630. Epub 2017 Dec 26.

Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), 08908 L'Hospitalet de Llobregat, Barcelona, Spain.

Pelizaeus-Merzbacher disease (PMD) is a fatal hypomyelinating disorder characterized by early impairment of motor development, nystagmus, choreoathetotic movements, ataxia and progressive spasticity. PMD is caused by variations in the proteolipid protein gene PLP1, which encodes the two major myelin proteins of the central nervous system, PLP and its spliced isoform DM20, in oligodendrocytes. Large duplications including the entire PLP1 gene are the most frequent causative mutation leading to the classical form of PMD. The Plp1 overexpressing mouse model (PLP-tg ) develops a phenotype very similar to human PMD, with early and severe motor dysfunction and a dramatic decrease in lifespan. The sequence of cellular events that cause neurodegeneration and ultimately death is poorly understood. In this work, we analyzed patient-derived fibroblasts and spinal cords of the PLP-tg mouse model, and identified redox imbalance, with altered antioxidant defense and oxidative damage to several enzymes involved in ATP production, such as glycolytic enzymes, creatine kinase and mitochondrial proteins from the Krebs cycle and oxidative phosphorylation. We also evidenced malfunction of the mitochondria compartment with increased ROS production and depolarization in PMD patient's fibroblasts, which was prevented by the antioxidant N-acetyl-cysteine. Finally, we uncovered an impairment of mitochondrial dynamics in patient's fibroblasts which may help explain the ultrastructural abnormalities of mitochondria morphology detected in spinal cords from PLP-tg mice. Altogether, these results underscore the link between redox and metabolic homeostasis in myelin diseases, provide insight into the pathophysiology of PMD, and may bear implications for tailored pharmacological intervention.
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http://dx.doi.org/10.1111/bpa.12571DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8028267PMC
September 2018

Biallelic mutations in the homeodomain of NKX6-2 underlie a severe hypomyelinating leukodystrophy.

Brain 2017 Oct;140(10):2550-2556

Unit of Neuromuscular and Neurodegnerative Disorders, Laboratory of Molecular Medicine, Bambino Gesu' Children's Hospital, Rome, Italy.

Hypomyelinating leukodystrophies are genetically heterogeneous disorders with overlapping clinical and neuroimaging features reflecting variable abnormalities in myelin formation. We report on the identification of biallelic inactivating mutations in NKX6-2, a gene encoding a transcription factor regulating multiple developmental processes with a main role in oligodendrocyte differentiation and regulation of myelin-specific gene expression, as the cause underlying a previously unrecognized severe variant of hypomyelinating leukodystrophy. Five affected subjects (three unrelated families) were documented to share biallelic inactivating mutations affecting the NKX6-2 homeobox domain. A trio-based whole exome sequencing analysis in the first family detected a homozygous frameshift change [c.606delinsTA; p.(Lys202Asnfs*?)]. In the second family, homozygosity mapping coupled to whole exome sequencing identified a homozygous nucleotide substitution (c.565G>T) introducing a premature stop codon (p.Glu189*). In the third family, whole exome sequencing established compound heterozygosity for a non-conservative missense change affecting a key residue participating in DNA binding (c.599G>A; p.Arg200Gln) and a nonsense substitution (c.589C>T; p.Gln197*), in both affected siblings. The clinical presentation was homogeneous, with four subjects having severe motor delays, nystagmus and absent head control, and one individual showing gross motor delay at the age of 6 months. All exhibited neuroimaging that was consistent with hypomyelination. These findings define a novel, severe form of leukodystrophy caused by impaired NKX6-2 function.
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http://dx.doi.org/10.1093/brain/awx207DOI Listing
October 2017

Mutation in the AGK gene in two siblings with unusual Sengers syndrome.

Metab Brain Dis 2017 12 3;32(6):2149-2154. Epub 2017 Sep 3.

Service de Génétique Médicale, Hôpital Estaing, Centre Hospitalier Universitaire de Clermont-Ferrand, Clermont-Ferrand, France.

Sengers syndrome is a rare autosomal recessive metabolic disorder caused by lack of acylglycerol kinase due to mutations in the AGK gene. It is characterized by congenital cataract, hypertrophic cardiomyopathy, myopathy and lactic acidosis. Two clinical forms have been described: a severe neonatal form, and a more benign form displaying exercise intolerance. We describe two siblings with congenital cataract, cardiomyopathy, hypotonia, intellectual disability and lactic acidosis. Whole exome sequencing revealed a homozygous c.1035dup mutation in the two siblings, supporting a diagnosis of Sengers syndrome. Our patients presented an intermediate form with intellectual deficiency, an unusual feature in Sengers syndrome. This permitted a prenatal diagnosis for a following pregnancy.
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http://dx.doi.org/10.1007/s11011-017-0101-6DOI Listing
December 2017
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