title: Novel KCNB1 mutation associated with non-syndromic intellectual disability.
abstract: Potassium voltage-gated channel subfamily B member 1 (KCNB1) encodes Kv2.1 potassium channel of crucial role in hippocampal neuron excitation homeostasis. KCNB1 mutations are known to cause early-onset infantile epilepsy. To date, 10 KCNB1 mutations have been described in 11 patients. Using whole-exome sequencing, we identified a novel de novo missense (c.1132G>C, p.V378L) KCNB1 mutation in a patient with global developmental delay, intellectual disability, severe speech impairment, but no episode of epilepsy until the lastly examined age of 6 years old. Furthermore, she showed neuropsychiatric symptoms including hyperactivity with irritability, heteroaggressiveness, psychomotor instability and agitation. Our observation might expand the phenotypic spectrum of KCNB1-related phenotypes and raises the issue of the occurrence of the epileptic phenotype.
authors.affiliation: Service de Génétique Médicale, Centre Hospitalier Universitaire de Nantes, Nantes, France.
authors.forename: Xénia
authors.initials: X
authors.lastname: Latypova
authors.affiliation: Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan.
authors.forename: Naomichi
authors.initials: N
authors.lastname: Matsumoto
authors.affiliation: Service de Pédiatrie, Hôpital Mère-Enfant, Centre Hospitalier Universitaire de Nantes, Nantes, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Vinceslas-Muller
authors.affiliation: Service de Génétique Médicale, Centre Hospitalier Universitaire de Nantes, Nantes, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Bézieau
authors.affiliation: Service de Génétique Médicale, Centre Hospitalier Universitaire de Nantes, Nantes, France.|INSERM, UMR-957, Laboratoire de Physiopathologie de la Résorption Osseuse et thérapie des tumeurs osseuses primitives, Nantes, France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Isidor
authors.affiliation: Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Miyake
mesh_terms: D000595:Amino Acid Sequence; D002675:Child, Preschool; D004569:Electroencephalography; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007223:Infant; D008607:Intellectual Disability / Q000235:genetics*; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D051669:Shab Potassium Channels / Q000737:chemistry / Q000235:genetics*; D013577:Syndrome
chemical_list: C496988:KCNB1 protein, human; D051669:Shab Potassium Channels