Marie Coutelier1, Lydie Burglen1, Emeline Mundwiller1, Myriam Abada-Bendib1, Diana Rodriguez1, Sandra Chantot-Bastaraud1, Christelle Rougeot1, Marie-Anne Cournelle1, Mathieu Milh1, Annick Toutain1, Delphine Bacq1, Vincent Meyer1, Alexandra Afenjar1, Jean-François Deleuze1, Alexis Brice1, Delphine Héron1, Giovanni Stevanin1, Alexandra Durr2. 1. From Institut du Cerveau et de la Moelle épinière (M.C., A.B., G.S., A.D.), ICM, Paris; CNRS (M.C., A.B., G.S., A.D.), UMR 7225, Paris; Sorbonne Universités (M.C., A.B., G.S., A.D.), UPMC Univ Paris 06, UMRS_1127, Paris; INSERM (M.C., E.M., A.B., G.S., A.D.), U 1127, Paris, France; Laboratory of Human Molecular Genetics (M.C.), de Duve Institute, Université catholique de Louvain, Brussels, Belgium; Laboratoire de Neurogénétique (M.C., G.S.), Ecole Pratique des Hautes Etudes, ICM, GHU Pitié-Salpêtrière, Paris; Centre de Référence Malformations et Maladies Congénitales du Cervelet (L.B., D.R., S.C.-B., C.R., A.A.), Paris-Lyon-Lille; INSERM U1141 (L.B., D.R.), Paris; APHP (L.B., S.C.-B.), Armand-Trousseau Hospital, Department of Genetics, Paris, France; Service de Neurologie (M.A.-B.), CHU Bab el Oued, Alger, Algeria; APHP (D.R., A.A.), Armand-Trousseau Hospital, Department of Neuropediatrics, UPMC Univ Paris 06; Hospices Civils de Lyon (C.R.), HFME, Service de Neuropédiatrie, Bron; Centre Hospitalier du Pays d'Aix (M.-A.C.), Service de Pédiatrie, Aix en Provence; APHM (M.M.), Service de neurologie pédiatrique, Hôpital de la Timone, Marseille; Service de Génétique (A.T.), Hôpital Bretonneau, Centre Hospitalier Universitaire, Tours; Centre National de Génotypage (D.B., V.M., J.-F.D.), Institut de Génomique, CEA, Evry; APHP (A.B., D.H., A.D.), Department of Genetics and Cytogenetics, Groupe Hospitalier Pitié-Salpêtrière, Paris; Centre de Référence Déficiences Intellectuelles de causes rares (D.H.), Paris; and Groupe de Recherche Clinique déficiences intellectuelles (D.H.), UPMC Univ Paris 06, France. 2. From Institut du Cerveau et de la Moelle épinière (M.C., A.B., G.S., A.D.), ICM, Paris; CNRS (M.C., A.B., G.S., A.D.), UMR 7225, Paris; Sorbonne Universités (M.C., A.B., G.S., A.D.), UPMC Univ Paris 06, UMRS_1127, Paris; INSERM (M.C., E.M., A.B., G.S., A.D.), U 1127, Paris, France; Laboratory of Human Molecular Genetics (M.C.), de Duve Institute, Université catholique de Louvain, Brussels, Belgium; Laboratoire de Neurogénétique (M.C., G.S.), Ecole Pratique des Hautes Etudes, ICM, GHU Pitié-Salpêtrière, Paris; Centre de Référence Malformations et Maladies Congénitales du Cervelet (L.B., D.R., S.C.-B., C.R., A.A.), Paris-Lyon-Lille; INSERM U1141 (L.B., D.R.), Paris; APHP (L.B., S.C.-B.), Armand-Trousseau Hospital, Department of Genetics, Paris, France; Service de Neurologie (M.A.-B.), CHU Bab el Oued, Alger, Algeria; APHP (D.R., A.A.), Armand-Trousseau Hospital, Department of Neuropediatrics, UPMC Univ Paris 06; Hospices Civils de Lyon (C.R.), HFME, Service de Neuropédiatrie, Bron; Centre Hospitalier du Pays d'Aix (M.-A.C.), Service de Pédiatrie, Aix en Provence; APHM (M.M.), Service de neurologie pédiatrique, Hôpital de la Timone, Marseille; Service de Génétique (A.T.), Hôpital Bretonneau, Centre Hospitalier Universitaire, Tours; Centre National de Génotypage (D.B., V.M., J.-F.D.), Institut de Génomique, CEA, Evry; APHP (A.B., D.H., A.D.), Department of Genetics and Cytogenetics, Groupe Hospitalier Pitié-Salpêtrière, Paris; Centre de Référence Déficiences Intellectuelles de causes rares (D.H.), Paris; and Groupe de Recherche Clinique déficiences intellectuelles (D.H.), UPMC Univ Paris 06, France. alexandra.durr@upmc.fr.
Abstract
OBJECTIVES: In a large family of Algerian origin, we aimed to identify the genetic mutation segregating with simultaneous presence of adult-onset, paucisymptomatic, slowly progressive, cerebellar ataxia in 7 adults and congenital ataxia in 1 child, and then to assess the involvement of GRID2 mutations in 144 patients with congenital cerebellar ataxia. METHODS: We used a combined approach of linkage analysis and whole-exome sequencing in one family, and a targeted gene panel sequencing approach in 144 congenital ataxias. RESULTS: In the large family with spinocerebellar ataxia, we identified a missense mutation (c.1966C>G/p.Leu656Val) in the GRID2 gene, in a heterozygous state in adults, and in a homozygous state in one child with congenital ataxia, compatible with a semidominant transmission pattern. In 144 patients affected with congenital ataxia, we identified 2 missense de novo GRID2 mutations in 2 children (c.1960G>A/p.Ala654Thr, c.1961C>A/p.Ala654Asp). They affect the same amino acid as the previously described Lurcher mutation in mice; the variant in the large family concerns a nearby amino acid. CONCLUSIONS: In humans, GRID2 had only been involved in ataxia through complete loss-of-function mutations due to exon deletions. We report the first point mutations in this gene, with putative gain-of-function mechanisms, and a semidominant transmission as was observed in the Lurcher mice model. Of note, cerebellar ataxia is the core phenotype, but with variable severity ranging from very mild adult-onset to congenital-onset ataxias linked to both the heterozygous and homozygous state of the variant, and the position of the mutation.
OBJECTIVES: In a large family of Algerian origin, we aimed to identify the genetic mutation segregating with simultaneous presence of adult-onset, paucisymptomatic, slowly progressive, cerebellar ataxia in 7 adults and congenital ataxia in 1 child, and then to assess the involvement of GRID2 mutations in 144 patients with congenital cerebellar ataxia. METHODS: We used a combined approach of linkage analysis and whole-exome sequencing in one family, and a targeted gene panel sequencing approach in 144 congenital ataxias. RESULTS: In the large family with spinocerebellar ataxia, we identified a missense mutation (c.1966C>G/p.Leu656Val) in the GRID2 gene, in a heterozygous state in adults, and in a homozygous state in one child with congenital ataxia, compatible with a semidominant transmission pattern. In 144 patients affected with congenital ataxia, we identified 2 missense de novo GRID2 mutations in 2 children (c.1960G>A/p.Ala654Thr, c.1961C>A/p.Ala654Asp). They affect the same amino acid as the previously described Lurcher mutation in mice; the variant in the large family concerns a nearby amino acid. CONCLUSIONS: In humans, GRID2 had only been involved in ataxia through complete loss-of-function mutations due to exon deletions. We report the first point mutations in this gene, with putative gain-of-function mechanisms, and a semidominant transmission as was observed in the Lurchermice model. Of note, cerebellar ataxia is the core phenotype, but with variable severity ranging from very mild adult-onset to congenital-onset ataxias linked to both the heterozygous and homozygous state of the variant, and the position of the mutation.
Authors: Sonja Martin; Adam Chamberlin; Deepali N Shinde; Maja Hempel; Tim M Strom; Allison Schreiber; Jessika Johannsen; Lilian Bomme Ousager; Martin J Larsen; Lars Kjaersgaard Hansen; Ali Fatemi; Julie S Cohen; Johannes Lemke; Kristina P Sørensen; Katherine L Helbig; Davor Lessel; Rami Abou Jamra Journal: Am J Hum Genet Date: 2017-12-07 Impact factor: 11.025
Authors: Jan Cendelin; Zdenka Purkartova; Jakub Kubik; Erik Ulbricht; Filip Tichanek; Yaroslav Kolinko Journal: Cerebellum Date: 2018-08 Impact factor: 3.847
Authors: Marie Coutelier; Iulia Blesneac; Arnaud Monteil; Marie-Lorraine Monin; Kunie Ando; Emeline Mundwiller; Alfredo Brusco; Isabelle Le Ber; Mathieu Anheim; Anna Castrioto; Charles Duyckaerts; Alexis Brice; Alexandra Durr; Philippe Lory; Giovanni Stevanin Journal: Am J Hum Genet Date: 2015-10-08 Impact factor: 11.025