Publications by authors named "Cyril Goizet"

155 Publications

Cardiovascular and connective tissue disorder features in FLNA-related PVNH patients: progress towards a refined delineation of this syndrome.

Orphanet J Rare Dis 2021 Dec 4;16(1):504. Epub 2021 Dec 4.

Département de génétique, Centre national de référence pour les maladies vasculaires rares, centre de référence européen VASCERN MSA, Hôpital Européen Georges Pompidou, AP-HP, 20 rue Leblanc, 75015, Paris, France.

Background: FLNA Loss-of-Function (LoF) causes periventricular nodular heterotopia type 1 (PVNH1), an acknowledged cause of seizures of various types. Neurological symptoms are inconstant, and cardiovascular (CV) defects or connective tissue disorders (CTD) have regularly been associated. We aimed at refining the description of CV and CTD features in patients with FLNA LoF and depicting the multisystemic nature of this condition.

Methods: We retrospectively evaluated FLNA variants and clinical presentations in FLNA LoF patient with at least one CV or CTD feature, from three cohorts: ten patients from the French Reference Center for Rare Vascular Diseases, 23 patients from the national reference diagnostic lab for filaminopathies-A, and 59 patients from literature review.

Results: Half of patients did not present neurological symptoms. Most patients presented a syndromic association combining CV and CTD features. CV anomalies, mostly aortic aneurysm and/or dilation were present in 75% of patients. CTD features were present in 75%. Variants analysis demonstrated an enrichment of coding variants in the CH1 domain of FLNA protein.

Conclusion: In FLNA LoF patients, the absence of seizures should not be overlooked. When considering a diagnosis of PVNH1, the assessment for CV and CTD anomalies is of major interest as they represent interlinked features. We recommend systematic study of FLNA within CTD genes panels, regardless of the presence of neurological symptoms.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13023-021-02128-1DOI Listing
December 2021

Implication of folate deficiency in CYP2U1 loss of function.

J Exp Med 2021 11 21;218(11). Epub 2021 Sep 21.

Department of Biochemistry and Molecular Biology, Hospices Civils de Lyon, Pierre Bénite, France.

Hereditary spastic paraplegias are heterogeneous neurodegenerative disorders. Understanding of their pathogenic mechanisms remains sparse, and therapeutic options are lacking. We characterized a mouse model lacking the Cyp2u1 gene, loss of which is known to be involved in a complex form of these diseases in humans. We showed that this model partially recapitulated the clinical and biochemical phenotypes of patients. Using electron microscopy, lipidomic, and proteomic studies, we identified vitamin B2 as a substrate of the CYP2U1 enzyme, as well as coenzyme Q, neopterin, and IFN-α levels as putative biomarkers in mice and fluids obtained from the largest series of CYP2U1-mutated patients reported so far. We also confirmed brain calcifications as a potential biomarker in patients. Our results suggest that CYP2U1 deficiency disrupts mitochondrial function and impacts proper neurodevelopment, which could be prevented by folate supplementation in our mouse model, followed by a neurodegenerative process altering multiple neuronal and extraneuronal tissues.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1084/jem.20210846DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8480666PMC
November 2021

Biallelic PI4KA variants cause a novel neurodevelopmental syndrome with hypomyelinating leukodystrophy.

Brain 2021 Oct;144(9):2659-2669

Division of Genetic Medicine, Department of Paediatrics, University of Washington, Seattle, WA 98195, USA.

Phosphoinositides are lipids that play a critical role in processes such as cellular signalling, ion channel activity and membrane trafficking. When mutated, several genes that encode proteins that participate in the metabolism of these lipids give rise to neurological or developmental phenotypes. PI4KA is a phosphoinositide kinase that is highly expressed in the brain and is essential for life. Here we used whole exome or genome sequencing to identify 10 unrelated patients harbouring biallelic variants in PI4KA that caused a spectrum of conditions ranging from severe global neurodevelopmental delay with hypomyelination and developmental brain abnormalities to pure spastic paraplegia. Some patients presented immunological deficits or genito-urinary abnormalities. Functional analyses by western blotting and immunofluorescence showed decreased PI4KA levels in the patients' fibroblasts. Immunofluorescence and targeted lipidomics indicated that PI4KA activity was diminished in fibroblasts and peripheral blood mononuclear cells. In conclusion, we report a novel severe metabolic disorder caused by PI4KA malfunction, highlighting the importance of phosphoinositide signalling in human brain development and the myelin sheath.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/brain/awab124DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8557332PMC
October 2021

High rate of hypomorphic variants as the cause of inherited ataxia and related diseases: study of a cohort of 366 families.

Genet Med 2021 11 7;23(11):2160-2170. Epub 2021 Jul 7.

Department of Clinical Genetics, Centre de Référence Maladies Rares Anomalies du Développement, CHU de Rennes, Rennes, France.

Purpose: Diagnosis of inherited ataxia and related diseases represents a real challenge given the tremendous heterogeneity and clinical overlap of the various causes. We evaluated the efficacy of molecular diagnosis of these diseases by sequencing a large cohort of undiagnosed families.

Methods: We analyzed 366 unrelated consecutive patients with undiagnosed ataxia or related disorders by clinical exome-capture sequencing. In silico analysis was performed with an in-house pipeline that combines variant ranking and copy-number variant (CNV) searches. Variants were interpreted according to American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines.

Results: We established the molecular diagnosis in 46% of the cases. We identified 35 mildly affected patients with causative variants in genes that are classically associated with severe presentations. These cases were explained by the occurrence of hypomorphic variants, but also rarely suspected mechanisms such as C-terminal truncations and translation reinitiation.

Conclusion: A significant fraction of the clinical heterogeneity and phenotypic overlap is explained by hypomorphic variants that are difficult to identify and not readily predicted. The hypomorphic C-terminal truncation and translation reinitiation mechanisms that we identified may only apply to few genes, as it relies on specific domain organization and alterations. We identified PEX10 and FASTKD2 as candidates for translation reinitiation accounting for mild disease presentation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41436-021-01250-6DOI Listing
November 2021

Evidence of mosaicism in SPAST variant carriers in four French families.

Eur J Hum Genet 2021 07 6;29(7):1158-1163. Epub 2021 May 6.

Sorbonne Université, AP-HP, GH Pitié-Salpêtrière, Département de génétique, Paris, France.

Hereditary spastic paraplegias (HSP) are heterogeneous disorders, with more than 70 causative genes. Variants in SPAST are the most frequent genetic etiology and are responsible for spastic paraplegia type 4 (SPG4). Age at onset can vary, even between patients from the same family, and incomplete penetrance is described. Somatic mosaicism is extremely rare with only three patients reported in the literature. We report here SPAST mosaic variants in four unrelated patients. We confirm that mosaicism in SPAST is a very rare event with only four identified cases on more than 300 patients with a SPAST variant previously described by our clinical diagnostic laboratory.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41431-021-00847-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8298572PMC
July 2021

SOD1-related ALS with anticipation in a large family from Martinique.

Amyotroph Lateral Scler Frontotemporal Degener 2021 11 23;22(7-8):545-551. Epub 2021 Mar 23.

Department of Medical Genetics, National Reference Center for Rare Diseases 'Neurogenetic', Pellegrin Hospital, Bordeaux University Hospital, Bordeaux, France and.

Amyotrophic Lateral Sclerosis (ALS) is a rare neurological disorder that causes degeneration of upper and lower motor neurons and their axons. ALS is mostly sporadic, but there are familial forms. In more than half of the familial forms, a pathogenic variant is found in one of the following genes: , , , , and . is the 2nd most common gene involved in genetic forms of ALS. Genotype-phenotype relationships are occasionally established in genetic forms of ALS associated with mutations pathogenic variants. The c.281G > T (p.[G93V]) variant in is associated with a rarely described and unexplained anticipation phenomenon. We report a large family from Martinique in whom ALS is associated with a c.281G > T (p.[G93V]) pathogenic variant in and a statistically suggested anticipation. A whole-exome study and detection of CNVs (CoDESeq) from 3 affected members of this family revealed the presence of variants of uncertain signification (VUS) in other ALS genes. VUS in and were present in patients of the 2nd generation, and CNVs involving and were found in the youngest case of the family.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/21678421.2021.1900870DOI Listing
November 2021

Increasing involvement of CAPN1 variants in spastic ataxias and phenotype-genotype correlations.

Neurogenetics 2021 03 23;22(1):71-79. Epub 2021 Jan 23.

Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, DMU Neuroscience 6, Paris, France.

Spastic ataxias are rare neurogenetic disorders involving spinocerebellar and pyramidal tracts. Many genes are involved. Among them, CAPN1, when mutated, is responsible for a complex inherited form of spastic paraplegia (SPG76). We report the largest published series of 21 novel patients with nine new CAPN1 disease-causing variants and their clinical characteristics from two European university hospitals (Paris and Stockholm). After a formal clinical examination, causative variants were identified by next-generation sequencing and confirmed by Sanger sequencing. CAPN1 variants are a rare cause (~ 1.4%) of young-adult-onset spastic ataxia; however, together with all published cases, they allowed us to better describe the clinical and genetic spectra of this form. Truncating variants are the most frequent, and missense variants lead to earlier age at onset in favor of an additional deleterious effect. Cerebellar ataxia with cerebellar atrophy, dysarthria and lower limb weakness are often associated with spasticity. We also suggest that cognitive impairment and depression should be assessed specifically in the follow-up of SPG76 cases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10048-020-00633-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7997841PMC
March 2021

Heterozygous Variants in KDM4B Lead to Global Developmental Delay and Neuroanatomical Defects.

Am J Hum Genet 2020 12 23;107(6):1170-1177. Epub 2020 Nov 23.

Division of Newborn Medicine, Department of Pediatrics, Boston Children's Hospital, Boston, MA 02115, USA; Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA. Electronic address:

KDM4B is a lysine-specific demethylase with a preferential activity on H3K9 tri/di-methylation (H3K9me3/2)-modified histones. H3K9 tri/di-demethylation is an important epigenetic mechanism responsible for silencing of gene expression in animal development and cancer. However, the role of KDM4B on human development is still poorly characterized. Through international data sharing, we gathered a cohort of nine individuals with mono-allelic de novo or inherited variants in KDM4B. All individuals presented with dysmorphic features and global developmental delay (GDD) with language and motor skills most affected. Three individuals had a history of seizures, and four had anomalies on brain imaging ranging from agenesis of the corpus callosum with hydrocephalus to cystic formations, abnormal hippocampi, and polymicrogyria. In mice, lysine demethylase 4B is expressed during brain development with high levels in the hippocampus, a region important for learning and memory. To understand how KDM4B variants can lead to GDD in humans, we assessed the effect of KDM4B disruption on brain anatomy and behavior through an in vivo heterozygous mouse model (Kdm4b), focusing on neuroanatomical changes. In mutant mice, the total brain volume was significantly reduced with decreased size of the hippocampal dentate gyrus, partial agenesis of the corpus callosum, and ventriculomegaly. This report demonstrates that variants in KDM4B are associated with GDD/ intellectual disability and neuroanatomical defects. Our findings suggest that KDM4B variation leads to a chromatinopathy, broadening the spectrum of this group of Mendelian disorders caused by alterations in epigenetic machinery.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ajhg.2020.11.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7820620PMC
December 2020

Late-onset presentation of neurometabolic diseases: diagnostic flowchart revisited.

Authors:
Cyril Goizet

J Neurol Neurosurg Psychiatry 2020 Oct 21. Epub 2020 Oct 21.

Reference Center for Rare Neurogenetic Diseases, Department of Medical Genetics, University Hospital Centre Bordeaux Pellegrin Hospital Group, Bordeaux, Aquitaine, France

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/jnnp-2020-324033DOI Listing
October 2020

Endocrine and Growth Abnormalities in 4H Leukodystrophy Caused by Variants in POLR3A, POLR3B, and POLR1C.

J Clin Endocrinol Metab 2021 01;106(2):e660-e674

Department of Child Neurology, University Children's Hospital Tübingen, Tübingen, Germany.

Context: 4H or POLR3-related leukodystrophy is an autosomal recessive disorder typically characterized by hypomyelination, hypodontia, and hypogonadotropic hypogonadism, caused by biallelic pathogenic variants in POLR3A, POLR3B, POLR1C, and POLR3K. The endocrine and growth abnormalities associated with this disorder have not been thoroughly investigated to date.

Objective: To systematically characterize endocrine abnormalities of patients with 4H leukodystrophy.

Design: An international cross-sectional study was performed on 150 patients with genetically confirmed 4H leukodystrophy between 2015 and 2016. Endocrine and growth abnormalities were evaluated, and neurological and other non-neurological features were reviewed. Potential genotype/phenotype associations were also investigated.

Setting: This was a multicenter retrospective study using information collected from 3 predominant centers.

Patients: A total of 150 patients with 4H leukodystrophy and pathogenic variants in POLR3A, POLR3B, or POLR1C were included.

Main Outcome Measures: Variables used to evaluate endocrine and growth abnormalities included pubertal history, hormone levels (estradiol, testosterone, stimulated LH and FSH, stimulated GH, IGF-I, prolactin, ACTH, cortisol, TSH, and T4), and height and head circumference charts.

Results: The most common endocrine abnormalities were delayed puberty (57/74; 77% overall, 64% in males, 89% in females) and short stature (57/93; 61%), when evaluated according to physician assessment. Abnormal thyroid function was reported in 22% (13/59) of patients.

Conclusions: Our results confirm pubertal abnormalities and short stature are the most common endocrine features seen in 4H leukodystrophy. However, we noted that endocrine abnormalities are typically underinvestigated in this patient population. A prospective study is required to formulate evidence-based recommendations for management of the endocrine manifestations of this disorder.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1210/clinem/dgaa700DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7823228PMC
January 2021

A new phenotype of choreic syndrome associating severe freezing of gait and chorea.

Clin Case Rep 2020 Sep 2;8(9):1806-1808. Epub 2020 Jun 2.

Institut des Maladies Neurodégénératives (IMN) Service de Neurologie CHU Bordeaux Bordeaux France.

The early onset of gait akinesia should not rule out the diagnosis of hereditary chorea. It would be helpful to proceed to a whole-genome and long-read sequencing in order to track a new pathogenic variant including noncoding repeat expansion.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ccr3.3008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7495783PMC
September 2020

The value of electrocardiography and echocardiography in distinguishing Fabry disease from sarcomeric hypertrophic cardiomyopathy.

Arch Cardiovasc Dis 2020 Aug - Sep;113(8-9):542-550. Epub 2020 Aug 6.

Department of Cardiology, Caen University Hospital, 14000 Caen, France; EA 4650 (Signalisation, électrophysiologie et imagerie des lésions d'ischémie-reperfusion myocardique), Medical School, Caen-Normandie University (UNICAEN), Caen University Hospital, 14000 Caen, France. Electronic address:

Background: Screening for Fabry disease is sub-optimal in non-specialised centres.

Aim: To assess the diagnostic value of electrocardiographic scores of left ventricular hypertrophy and a combined electrocardiographic and echocardiographic model in Fabry disease.

Methods: We retrospectively reviewed the electrocardiograms and echocardiograms of 61 patients (mean age 55.6±11.5 years; 57% men) with Fabry disease and left ventricular hypertrophy, and compared them with those from 59 patients (mean age 44.8±18.3 years; 66% men) with sarcomeric hypertrophic cardiomyopathy. Six electrocardiography criteria for left ventricular hypertrophy were specifically analysed: Sokolow-Lyon voltage index; Cornell voltage index; Gubner index; Romhilt-Estes score; Sokolow-Lyon product (voltage index×QRS duration); and Cornell product (voltage index×QRS duration).

Results: Right bundle branch block was more frequent in patients with Fabry disease (54% vs. 22%; P=0.001). QRS duration, Gubner score and Sokolow-Lyon product were significantly higher in patients with Fabry disease. Maximal wall thickness was higher in patients with sarcomeric hypertrophic cardiomyopathy (21.9±5.1 vs. 15.5±2.9mm; P<0.001). Indexed sinus of Valsalva diameter was larger in patients with Fabry disease. After multivariable analysis, right bundle branch block, Sokolow-Lyon product, maximal wall thickness and aortic diameter were independently associated with Fabry disease. A model including these four variables yielded an area under the receiver operating characteristic curve of 0.918 (95% confidence interval 0.868-0.968) for Fabry disease.

Conclusion: Our model combining easy-to-assess electrocardiographic and echocardiographic variables may be helpful in improving screening and reducing diagnosis delay in Fabry disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.acvd.2020.04.008DOI Listing
September 2020

Clinical, neuropathological, and genetic characterization of STUB1 variants in cerebellar ataxias: a frequent cause of predominant cognitive impairment.

Genet Med 2020 11 27;22(11):1851-1862. Epub 2020 Jul 27.

Sorbonne Université, Institut du Cerveau-Paris Brain Institute (ICM), AP-HP, INSERM, CNRS, University Hospital Pitié-Salpêtrière, Paris, France.

Purpose: Pathogenic variants in STUB1 were initially described in autosomal recessive spinocerebellar ataxia type 16 and dominant cerebellar ataxia with cerebellar cognitive dysfunction (SCA48).

Methods: We analyzed a large series of 440 index cerebellar ataxia cases, mostly with dominant inheritance.

Results: STUB1 variants were detected in 50 patients. Age at onset and severity were remarkably variable. Cognitive impairment, predominantly frontal syndrome, was observed in 54% of STUB1 variant carriers, including five families with Huntington or frontotemporal dementia disease-like phenotypes associated with ataxia, while no STUB1 variant was found in 115 patients with frontotemporal dementia. We report neuropathological findings of a STUB1 heterozygous patient, showing massive loss of Purkinje cells in the vermis and major loss in the cerebellar hemispheres without atrophy of the pons, hippocampus, or cerebral cortex. This screening of STUB1 variants revealed new features: (1) the majority of patients were women (70%) and (2) "second hits" in AFG3L2, PRKCG, and TBP were detected in three families suggesting synergic effects.

Conclusion: Our results reveal an unexpectedly frequent (7%) implication of STUB1 among dominantly inherited cerebellar ataxias, and suggest that the penetrance of STUB1 variants could be modulated by other factors, including sex and variants in other ataxia-related genes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41436-020-0899-xDOI Listing
November 2020

MRI of neurodegeneration with brain iron accumulation.

Curr Opin Neurol 2020 08;33(4):462-473

Paris Brain Institute, Institut du Cerveau et de la Moelle épinière - ICM, INSERM U 1127, CNRS UMR 7225, Sorbonne Université, Team 'Movement Investigations and Therapeutics' (MOV'IT).

Purpose Of Review: The diagnosis of neurodegeneration with brain iron accumulation (NBIA) typically associates various extrapyramidal and pyramidal features, cognitive and psychiatric symptoms with bilateral hypointensities in the globus pallidus on iron-sensitive magnetic resonance images, reflecting the alteration of iron homeostasis in this area. This article details the contribution of MRI in the diagnosis by summarizing and comparing MRI patterns of the various NBIA subtypes.

Recent Findings: MRI almost always shows characteristic changes combining iron accumulation and additional neuroimaging abnormalities. Iron-sensitive MRI shows iron deposition in the basal ganglia, particularly in bilateral globus pallidus and substantia nigra. Other regions may be affected depending on the NBIA subtypes including the cerebellum and dentate nucleus, the midbrain, the striatum, the thalamus, and the cortex. Atrophy of the cerebellum, brainstem, corpus callosum and cortex, and white matter changes may be associated and worsen with disease duration. Iron deposition can be quantified using R2 or quantitative susceptibility mapping.

Summary: Recent MRI advances allow depicting differences between the various subtypes of NBIA, providing a useful analytical framework for clinicians. Standardization of protocols for image acquisition and analysis may help improving the detection of imaging changes associated with NBIA and the quantification of iron deposition.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/WCO.0000000000000844DOI Listing
August 2020

High diagnostic value of plasma Niemann-Pick type C biomarkers in adults with selected neurological and/or psychiatric disorders.

J Neurol 2020 Nov 26;267(11):3371-3377. Epub 2020 Jun 26.

Neurology Department, Reference Center for Lysosomal Diseases, Neurogenetics and Metabolism Unit, Hôpital Pitié-Salpêtrière, 47-83 boulevard de l'Hôpital, 75013, Paris, France.

Late-onset Niemann-Pick type C (NP-C) is a rare, underdiagnosed lysosomal disease with neurological manifestations. A specific treatment, miglustat, can stabilize the disease if given early. Recently, three plasma screening biomarkers (PSBs) were developed [cholestane3β,5α,6βtriol (C-triol), 7-ketocholesterol (7-KC), and lysosphingomyelin-509 (LSM-509)], allowing a simpler and quite robust screening of patients suitable for genetic testing. The objective of our study was to evaluate practical utility and feasibility of large-scale PSB screening for NP-C in selected adult patients. Patients were prospectively enrolled if they showed, starting from 12 years of age, at least one of the three initial neuro-psychiatric manifestations described in NP-C: (1) gait disorder (cerebellar and/or dystonic); (2) cognitive decline with frontal lobe syndrome; (3) atypical psychosis. PSBs were measured in plasma of all patients and, if positive (LSM-509 and/or C-triol + 7-KC elevated), sequencing of NPC1 and NPC2 genes was performed. A total of 251 patients [136 males, 115 females; median age 42.1 (range 12.2-85.6) years] were screened. Six patients had positive PSBs. Two were confirmed to have NP-C (0.8% diagnostic yield, both with all three PSBs highly increased, especially LSM-509). False-positive rate was 1.2%, which was identical if only considering LSM-509. By contrast, false-positive rates were 8.1% and 5.7% for 7-KC and C-triol, respectively. We showed that selecting patients with neurologic and/or psychiatric symptoms consistent with NP-C for large-scale PSB screening is a simple and valid strategy to identify new adult NP-C patients, and would probably lead to earlier diagnosis and treatment administration if widely applied.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00415-020-10020-4DOI Listing
November 2020

Rare variants in the GABA receptor subunit ε identified in patients with a wide spectrum of epileptic phenotypes.

Mol Genet Genomic Med 2020 09 25;8(9):e1388. Epub 2020 Jun 25.

Junior Research Group, Genetics of Childhood Brain Malformations, Faculty VI-School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany.

Background: Epilepsy belongs to a group of chronic and highly heterogeneous brain disorders. Many types of epilepsy and epileptic syndromes are caused by genetic factors. The neural amino acid y-aminobutyric acid (GABA) is a major inhibitory neurotransmitter in the mammalian central nervous system. It regulates activity of channel pores by binding to transmembrane GABA-receptors (GABRs). The GABRs are heteropentamers assembled from different receptor subunits (α1-6, β1-3, γ1-3, δ, ε, θ, π, and ρ1-3). Several epileptic disorders are caused by mutations in genes encoding single GABRs.

Methods: We applied trio- and single-whole exome sequencing to search for genetic sequence variants associated with a wide range of epileptic phenotypes accompanied by intellectual disability and/or global developmental delay in the investigated patients.

Results: We identified four hemizygous sequence variants in the GABA receptor subunit ε gene (GABRE), including one nonsense (NM_004961.3: c.399C>A, p.Tyr133*), two missense variants (NM_004961.3: c.664G>A, p.Glu222Lys; NM_004961.3: c.1045G>A, p.Val349Ile), and one variant affecting the translation initiation codon (NM_004961.3: c.1A>G, p.Met1?) in four unrelated families.

Conclusion: Our clinical and molecular genetic findings suggest that GABRE is a likely candidate gene for epilepsy. Nevertheless, functional studies are necessary to better understand pathogenicity of the GABRE-mutations and their associations with epileptic phenotypes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/mgg3.1388DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7507344PMC
September 2020

Single Circulating Fetal Trophoblastic Cells Eligible for Non Invasive Prenatal Diagnosis: the Exception Rather than the Rule.

Sci Rep 2020 06 17;10(1):9861. Epub 2020 Jun 17.

Laboratoire de Génétique de Maladies Rares, Institut Universitaire de Recherche Clinique, EA7402 Université de Montpellier, CHU Montpellier, Montpellier, France.

Non-Invasive Prenatal Diagnosis (NIPD), based on the analysis of circulating cell-free fetal DNA (cff-DNA), is successfully implemented for an increasing number of monogenic diseases. However, technical issues related to cff-DNA characteristics remain, and not all mutations can be screened with this method, particularly triplet expansion mutations that frequently concern prenatal diagnosis requests. The objective of this study was to develop an approach to isolate and analyze Circulating Trophoblastic Fetal Cells (CFTCs) for NIPD of monogenic diseases caused by triplet repeat expansion or point mutations. We developed a method for CFTC isolation based on DEPArray sorting and used Huntington's disease as the clinical model for CFTC-based NIPD. Then, we investigated whether CFTC isolation and Whole Genome Amplification (WGA) could be used for NIPD in couples at risk of transmitting different monogenic diseases. Our data show that the allele drop-out rate was 3-fold higher in CFTCs than in maternal cells processed in the same way. Moreover, we give new insights into CFTCs by compiling data obtained by extensive molecular testing by microsatellite multiplex PCR genotyping and by WGA followed by mini-exome sequencing. CFTCs appear to be often characterized by a random state of genomic degradation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-020-66923-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7300110PMC
June 2020

Mutations in the m-AAA proteases AFG3L2 and SPG7 are causing isolated dominant optic atrophy.

Neurol Genet 2020 Jun 20;6(3):e428. Epub 2020 May 20.

MitoLab Team (M.C., A.C., C.B., D.G., V.D.-D., S.L., V.P., P.R., D.B., P.A.-B., G.L.), UMR CNRS 6015-INSERM U1083, Institut MitoVasc, Angers University and Hospital; Genetics and immuno-cell therapy Team (M.C.), Mohammed First University, Oujda, Morocco; Departments of Biochemistry and Genetics (C.B., D.G., V.D.-D., E.C., V.P., P.R., D.B., P.A.-B.), University Hospital Angers; Department of Ophthalmology (A.M.), Centre Hospitalier Universitaire Saint-Pierre, Brussels, Belgium; Neuroophthalmology Department (C.V.), Rothschild Ophthalmologic Foundation, Paris; Exploration of Visual Function and Neuro-Ophthalmology Department (V.S., S.D.-D., I.D.B.), Lille University Hospital, Rue Emilie Laine, Lille Cedex; CHU Bordeaux (C.G.), Service de Génétique Médicale, Centre de Référence « Neurogénétique » and Université de Bordeaux, INSERM U 1211, Laboratoire Maladies Rares, Génétique et Métabolisme (MRGM) Bordeaux; School of Optometry and Vision Sciences (M.V.), Cardiff University and Cardiff Eye Unit, University Hospital of Wales; NIHR Biomedical Research Centre at Moorfields Eye Hospital and UCL Institute of Ophthalmology (N.J., P.Y.-W.-M.), London; Department of Clinical Neurosciences (P.Y.-W.-M.), Cambridge Centre for Brain Repair and MRC Mitochondrial Biology Unit, University of Cambridge; Cambridge Eye Unit (P.Y.-W.-M.), Addenbrooke's Hospital, Cambridge University Hospitals, UK; IRCCS Istituto Delle Scienze Neurologiche di Bologna (F.T., L.C., C.L.M., V.C.), Bellaria Hospital; Unit of Neurology (C.L.M., V.C.), Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Italy; Centre de Compétence Maladies Rares (X.Z.), Clinique Pluridisciplinaire Jules Verne, Nantes; and National Centre in Rare Diseases (I.M.), Genetics of Sensory Diseases, University Hospital, Montpellier, France.

Objective: To improve the genetic diagnosis of dominant optic atrophy (DOA), the most frequently inherited optic nerve disease, and infer genotype-phenotype correlations.

Methods: Exonic sequences of 22 genes were screened by new-generation sequencing in patients with DOA who were investigated for ophthalmology, neurology, and brain MRI.

Results: We identified 7 and 8 new heterozygous pathogenic variants in and . Both genes encode for mitochondrial matricial AAA (m-AAA) proteases, initially involved in recessive hereditary spastic paraplegia type 7 (HSP7) and dominant spinocerebellar ataxia 28 (SCA28), respectively. Notably, variants in that result in DOA are located in different domains to those reported in SCA28, which likely explains the lack of clinical overlap between these 2 phenotypic manifestations. In comparison, the variants identified in DOA are interspersed among those responsible for HSP7 in which optic neuropathy has previously been reported.

Conclusions: Our results position and as candidate genes to be screened in DOA and indicate that regulation of mitochondrial protein homeostasis and maturation by m-AAA proteases are crucial for the maintenance of optic nerve physiology.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1212/NXG.0000000000000428DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7251510PMC
June 2020

Characterization of Fabry Disease cardiac involvement according to longitudinal strain, cardiometabolic exercise test, and T1 mapping.

Int J Cardiovasc Imaging 2020 Jul 8;36(7):1333-1342. Epub 2020 May 8.

Bordeaux University Hospital, 33000, Bordeaux, France.

In Anderson-Fabry disease (FD), we sought to evaluate relation between left ventricular (LV) hypertrophy, longitudinal strain (LS), myocardial T1 mapping and cardiopulmonary exercise parameters, and their prognostic value in term of cardiovascular outcomes. In this prospective, observational, monocentric study called "FABRY-Image", we evaluated consecutive adult FD patients by echocardiography, cardiac magnetic resonance, and cardiopulmonary exercise testing. We investigated regional LS, the relations between LV hypertrophy, LS, T1 mapping, and VO2 peak and VE/VCO2, and the prediction of cardiovascular events during follow-up. From 2016 to 2019, we included 35 FD patients (44 ± 17 years, 40% male), that were compared with 20 controls. In FD patients, global, basal and mid-LV LS, as well as mean T1 were significantly altered compared to controls (p < 0.05) with relative apical LS sparing. LV wall thickness was particularly related to mean of basal LS (r =  - 0.73), to T1 (r =  - 0.48), and to VE/VCO2 (r = 0.45). Mean of basal LS was well related to myocardial T1 (r = 0.59). A good relation was observed between VO2 peak and global LS (r = 0.39) while VE/VCO2 slope was more related to maximal LV wall thickness (r = 0.45), and T1 (r =  - 0.61). During a median follow-up of 2.4 years, 6/31 patients presented de novo atrial fibrillation or stroke. In Cox univariate analyses, LV wall thickness, basal LS, T1 value, and VE/VCO2 were significantly predictive of occurrence of de novo atrial fibrillation or stroke (p < 0.05). Our study shows an apical LS sparing in FD patients as observed in amyloidosis, and a close relation between LV hypertrophy, LS, T1 mapping, and VE/VCO2 which are all associated to the occurrence of de novo atrial fibrillation or TIA/stroke during follow-up. These results need to be confirmed by future multicentric studies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10554-020-01823-7DOI Listing
July 2020

Excess of de novo variants in genes involved in chromatin remodelling in patients with marfanoid habitus and intellectual disability.

J Med Genet 2020 07 10;57(7):466-474. Epub 2020 Apr 10.

Centre de Compétence Anomalies du Développement et Syndromes Malformatifs Sud-Est, CHI de Toulon - La Seyne-sur-Mer, France.

Purpose: Marfanoid habitus (MH) combined with intellectual disability (ID) (MHID) is a clinically and genetically heterogeneous presentation. The combination of array CGH and targeted sequencing of genes responsible for Marfan or Lujan-Fryns syndrome explain no more than 20% of subjects.

Methods: To further decipher the genetic basis of MHID, we performed exome sequencing on a combination of trio-based (33 subjects) or single probands (31 subjects), of which 61 were sporadic.

Results: We identified eight genes with de novo variants (DNVs) in at least two unrelated individuals ( and ). Using simulation models, we showed that five genes ( and ) met conservative Bonferroni genomewide significance for an excess of the observed de novo point variants. Overall, at least one pathogenic or likely pathogenic variant was identified in 54.7% of subjects (35/64). These variants fell within 27 genes previously associated with Mendelian disorders, including and , which are known to be mutated in overgrowth syndromes.

Conclusion: We demonstrated that DNVs were enriched in chromatin remodelling (p=2×10) and genes regulated by the fragile X mental retardation protein (p=3×10), highlighting overlapping genetic mechanisms between MHID and related neurodevelopmental disorders.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/jmedgenet-2019-106425DOI Listing
July 2020

TAR syndrome: Clinical and molecular characterization of a cohort of 26 patients and description of novel noncoding variants of RBM8A.

Hum Mutat 2020 07 6;41(7):1220-1225. Epub 2020 Apr 6.

Clinical Genetics Department, Reference Center for Developmental Anomalies, CHU Lille, Lille, France.

Thrombocytopenia-absent radius (TAR) syndrome is characterized by radial defect and neonatal thrombocytopenia. It is caused by biallelic variants of RBM8A gene (1q21.1) with the association of a null allele and a hypomorphic noncoding variant. RBM8A encodes Y14, a core protein of the exon junction complex involved in messenger RNA maturation. To date, only two hypomorphic variants have been identified. We report on a cohort of 26 patients affected with TAR syndrome and carrying biallelic variants in RBM8A. Half patients carried a 1q21.1 deletion and one of the two known hypomorphic variants. Four novel noncoding variants of RBM8A were identified in the remaining patients. We developed experimental models enabling their functional characterization in vitro. Two variants, located respectively in the 5'-untranslated region (5'-UTR) and 3'-UTR regions, are responsible for a diminished expression whereas two intronic variants alter splicing. Our results bring new insights into the molecular knowledge of TAR syndrome and enabled us to propose genetic counseling for patients' families.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/humu.24021DOI Listing
July 2020

Expanding the Spectrum of Neurological Manifestations in Cutis Laxa, Autosomal Recessive, Type IIIA.

Neuropediatrics 2020 08 6;51(4):245-250. Epub 2020 Mar 6.

Service de Neurologie Pédiatrique, CHU de Bordeaux, Bordeaux, France.

Cutis laxa is a heterogeneous group of diseases, characterized by abundant and wrinkled skin and a variable degree of intellectual disability. Cutis laxa, autosomal recessive, type IIIA and autosomal dominant 3 syndromes are caused by autosomal recessive or de novo pathogenic variants in . Autosomal recessive variants are known to lead to the most severe neurological phenotype, and very few patients have been described.We describe a 13-month-old patient with cutis laxa, autosomal recessive, type IIIA, with an extremely severe phenotype, including novel neurological findings. This description enlarges the neurological spectrum associated to cutis laxa, autosomal recessive, type IIIA, and provides an additional description of this syndrome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1055/s-0040-1701671DOI Listing
August 2020

Clinical spectrum of POLR3-related leukodystrophy caused by biallelic pathogenic variants.

Neurol Genet 2019 Dec 30;5(6):e369. Epub 2019 Oct 30.

Department of Neurology and Neurosurgery (L.G., L.T.T., K.G., G.B.), McGill University, Montreal, Canada; Department of Pediatrics (L.G., L.T.T., K.G., G.B.), McGill University, Montreal, Canada; Division of Clinical and Metabolic Genetics and Division of Neurology (L.G., G.Y.), The Hospital for Sick Children, University of Toronto, Toronto, Canada; Department of Child Neurology (F.K.C., M.S.V.D.K., N.I.W.), Emma Children's Hospital, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, and Amsterdam Neuroscience, Amsterdam, The Netherlands; Department of Clinical Genetics (F.K.C., R.M.V.S.), VU University Medical Center, Amsterdam, The Netherlands; Department of Human Genetics (F.K.C.), Center for Biomedical Research, Diponegoro University, Semarang, Indonesia; Department of Pediatrics (L.S.), Faculty of Medicine, University of Szeged, Szeged, Hungary; Child Health and Human Development Program (L.T.T., K.G., G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Division of Medical Genetics, Department of Specialized Medicine (L.T.T., K.G., G.B.), McGill University Health Center, Montreal, Canada; Centre de Référence Neurogénétique (F.H., C.G.), Service de Génétique, CHU Bordeaux, Bordeaux, France; Department of Pediatrics (E.L.F.), Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China; Developmental Neurology Department (S.D.A.), Fondazione IRCCS Istituto Neurologico C. Besta, Milan, Italy; Neuroscience and Neurorehabilitation Department (G.V.), Bambino Gesu Children's Hospital, Rome, Italy; Center for Pediatric Genomic Medicine (I.T.), Children's Mercy Hospitals and Clinics, Kansas City, MO; University of Missouri-Kansas City School of Medicine (I.T.), Kansas City, MO; Department of Pathology and Laboratory Medicine (I.T.), Children's Mercy Hospitals, Kansas City, MO; Department of Pediatrics (D.M.N.), Section of Medical Genetics, Ochsner for Children, New Orleans, LA; GeneDx (R.P.), Gaithersburg, MD; Division of Neurology (K.S.L.), Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ; Department of Pediatric Neurology (E.W.), Birmingham Children's Hospital, Birmingham, United Kingdom; Department of Medical Genetics (T.P.), Telemark Hospital, Skien, Norway; Department of Paediatric Neurology (P.F.), St Georges University Hospital NHS Foundation Trust, London, United Kingdom; Clinical Genetics Service (M.M.), St George's University Hospitals NHS Foundation Trust, London, United Kingdom; Clinical Genetics Department (J.R.), Royal Devon and Exeter Hospital NHS Trust, Exeter, United Kingdom; Department of Neurology and Neurosurgery (R.W.), The Children's Hospital at Westmead, Westmead, New South Wales, Australia; Center of Developmental Neurology (H.P.), Frankfurt, Germany; Department of Neurology (B.V.D.W.), Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Neurology (D.T.), Essen University Hospital, University of Duisburg-Essen, Essen, Germany; Department of Clinical Genetics (A.D., C.S.), Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom; Wellcome Sanger Institute (DDD Study), Wellcome Genome Campus, Cambridge, United Kingdom; Department of Pediatrics (N.T.), Division of Child Neurology, University of Texas Health Science Center, Houston, TX, United States of America; Movement Disorders Center and Neurogenetics Research Program (M.C.K.), Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ; Program in Neuroscience (M.C.K.), Arizona State University, Tempe, AZ, United States of America; Division of Neurology (S.S.), Department of Pediatrics, Lady Hardinge Medical College and Associated Kalawati Saran Children's Hospital, New Delhi, India; Division of Neurology (A.V.), Children's Hospital of Philadelphia, Philadelphia, PA; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America; Department of Child Neurology (D.T.), Neurological Institute C. Besta Foundation IRCCS, Milan, Italy; Department of Functional Genomics (M.S.V.D.K.), VU University, Amsterdam, The Netherlands; Unit of Neuromuscular and Neurodegenerative Disorders (E.B.), Laboratory of Molecular Medicine, Bambino Gesu Children's Hospital, Rome, Italy; Laboratoire MRGM, INSERM U1211, University Bordeaux, Bordeaux, France; Université de Bordeaux (S.F.), INSERM U1212, CNRS 5320, Bordeaux, France; and Department of Human Genetics (G.B.), McGill University, Montreal, Canada.

Objective: To determine the clinical, radiologic, and molecular characteristics of RNA polymerase III-related leukodystrophy (POLR3-HLD) caused by biallelic pathogenic variants.

Methods: A cross-sectional observational study involving 25 centers worldwide was conducted. Clinical and molecular information was collected on 23 unreported and previously reported patients with POLR3-HLD and biallelic pathogenic variants in . Brain MRI studies were reviewed.

Results: Fourteen female and 9 male patients aged 7 days to 23 years were included in the study. Most participants presented early in life (birth to 6 years), and motor deterioration was seen during childhood. A notable proportion of patients required a wheelchair before adolescence, suggesting a more severe phenotype than previously described in POLR3-HLD. Dental, ocular, and endocrine features were not invariably present (70%, 50%, and 50%, respectively). Five patients (22%) had a combination of hypomyelinating leukodystrophy and abnormal craniofacial development, including 1 individual with clear Treacher Collins syndrome (TCS) features. Brain MRI revealed hypomyelination in all cases, often with areas of pronounced T2 hyperintensity corresponding to T1 hypointensity of the white matter. Twenty-nine different pathogenic variants (including 12 new disease-causing variants) in were identified.

Conclusions: This study provides a comprehensive description of POLR3-HLD caused by biallelic pathogenic variants based on the largest cohort of patients to date. These results suggest distinct characteristics of POLR1C-related disorder, with a spectrum of clinical involvement characterized by hypomyelinating leukodystrophy with or without abnormal craniofacial development reminiscent of TCS.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1212/NXG.0000000000000369DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6927361PMC
December 2019

Natural History of Adult Patients with GM2 Gangliosidosis.

Ann Neurol 2020 04 7;87(4):609-617. Epub 2020 Feb 7.

Department of Neurology, Reference Center for Lysosomal Diseases, Neuro-Genetic and Metabolism Unit, Pitié-Salpêtrière University Hospital Group (Assistance publique Hôpitaux de Paris (AP-HP)), Paris.

Objective: GM2 gangliosidoses are lysosomal diseases due to biallelic mutations in the HEXA (Tay-Sachs disease [TS]) or HEXB (Sandhoff disease [SD]) genes, with subsequent low hexosaminidase(s) activity. Most patients have childhood onset, but some experience the first symptoms during adolescence/adulthood. This study aims to clarify the natural history of adult patients with GM2 gangliosidosis.

Methods: We retrospectively described 12 patients from a French cohort and 45 patients from the literature.

Results: We observed 4 typical presentations: (1) lower motoneuron disorder responsible for proximal lower limb weakness that subsequently expanded to the upper limbs, (2) cerebellar ataxia, (3) psychosis and/or severe mood disorder (only in the TS patients), and (4) a complex phenotype mixing the above 3 manifestations. The psoas was the first and most affected muscle in the lower limbs, whereas the triceps and interosseous were predominantly involved in the upper limbs. A longitudinal study of compound motor action potentials showed a progressive decrease in all nerves, with different kinetics. Sensory potentials were sometimes abnormally low, mainly in the SD patients. The main brain magnetic resonance imaging feature was cerebellar atrophy, even in patients without cerebellar symptoms. The prognosis was mainly related to gait disorder, as we showed that beyond 20 years of disease evolution, half of the patients were wheelchair users.

Interpretation: Improved knowledge of GM2 gangliosidosis in adults will help clinicians achieve correct diagnoses and better inform patients on the evolution and prognosis. It may also contribute to defining proper outcome measures when testing emerging therapies. ANN NEUROL 2020;87:609-617.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ana.25689DOI Listing
April 2020

Adult onset tubulo-interstitial nephropathy in MT-ND5-related phenotypes.

Clin Genet 2020 04 9;97(4):628-633. Epub 2020 Jan 9.

Service de Néphrologie Transplantation Dialyse et Aphérèses, Centre Hospitalier Universitaire de Bordeaux, Bordeaux, France.

Kidney is a highly adenosine triphosphate dependent organ in human body. Healthy and functional mitochondria are essential for normal kidney function. Clinical and genetic variability are the hallmarks of mitochondrial disorders. We report here the involvement of two MT-ND5 pathogenic variants encoding for ND5 subunit of respiratory chain complex I, the m.13513G>A and the m.13514A>G, in adult-onset kidney disease in three unrelated patients. The first patient had myopathy encephalopathy lactic acidosis and stroke syndrome, left ventricular hypertrophy with Wolff-Parkinson-White syndrome and tubulo-interstitial kidney disease. The second presented Leber hereditary optic neuropathy associated with tubulo-interstitial kidney disease. The third presented with an isolated chronic tubulo-interstitial kidney disease. These mutations have never been associated with adulthood mitochondrial nephropathy. These case reports highlight the importance to consider mitochondrial dysfunction in tubulo-interstitial kidney disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/cge.13670DOI Listing
April 2020

Oxidative stress contributes differentially to the pathophysiology of Charcot-Marie-Tooth disease type 2K.

Exp Neurol 2020 01 23;323:113069. Epub 2019 Oct 23.

MitoLab, UMR CNRS 6015-INSERM 1083, MitoVasc Institute, University of Angers, Angers, France; University Hospital of Angers, Department of Biochemistry and Genetics, F-49100 Angers, France.

Charcot-Marie-Tooth (CMT) disease is a common inherited peripheral neuropathy. The CMT2K axonal form is associated with GDAP1 dominant mutations, which according to the affected domain cause a gradient of severity. Indeed, the p.C240Y mutation, located within GDAP1 glutathione S-transferase (GST) domain and associated to a mitochondrial complex I defect, is related to a faster disease progression, compared to other mutations, such as the p.R120W located outside the GST domain. Here, we analysed the pathophysiology of six CMT2K fibroblast cell lines, carrying either the p.C240Y or p.R120W mutations. We show that complex I deficiency leads to a redox potential alteration and a significant reduction of sirtuin 1 (SIRT1) expression, a major deacetylase sensitive to the cellular redox state, and NRF1 the downstream target of SIRT1. In addition, we disclosed that the p.C240Y mutation is associated with a greater mitochondrial oxidative stress than the p.R120W mutation. Moreover, complex I activity is further restored in CMT2K mutant cell lines exposed to resveratrol. Together, these results suggest that the reduction of oxidative stress may constitute a promising therapeutic strategy for CMT2K.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.expneurol.2019.113069DOI Listing
January 2020

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/mgg3.839DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6732311PMC
September 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.

View Article and Find Full Text PDF

Download full-text PDF

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

Coexistence of schwannomatosis and glioblastoma in two families.

Eur J Med Genet 2019 Aug 22;62(8):103680. Epub 2019 May 22.

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

Schwannomatosis is a rare affection predisposing to multiple peripheral neurologic tumors development. Approximatively, one third of patients with schwannomatosis are carriers of a germline mutation in LZTR1 (Leucin Zipper Transcription Regulator 1). Tumorigenesis in schwannomatosis responds to a somatic 5-hit/3-step mechanism resulting in a loss of function (LOF) of LZTR1 and the contiguous genes of locus 22q11.2q12.2. Effectively, LZTR1 is mapped on 22q11.2 and centromeric to SMARCB1 also implicated in the determinism of schwannomatosis and NF2, responsible for neurofibromatosis type 2. On a somatic point of view, LZTR1 mutations are known to drive with a significant frequency glioblastoma (GB) development. We report here two families in which segregate both multiple schwannomas and GB. In the first family, the proband received a diagnosis with of schwannomatosis after a surgery for a lumbar schwannoma at age 43, molecularly confirmed by identification of a germline heterozygous mutation in LZTR1. Her father, having unremarkable medical history deceased from an apparently isolated GB at age 59. In the second family, LZTR1-related schwannomatosis was diagnosed in the index case at age 70 after multiple schwannomas surgeries. Her elder sister had no neurological medical history before occurrence of a lethal GB at age 78. Molecular analysis of GB sample from both affected relatives showed the presence of the familial mutation. These observations hypothesize a potential link between schwannomatosis and the GB development.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ejmg.2019.103680DOI Listing
August 2019
-->