Amelioration of a neurodevelopmental disorder by carbamazepine in a case having a gain-of-function GRIA3 variant.
Hum Genet
; 141(2): 283-293, 2022 Feb.
Article
em En
| MEDLINE
| ID: mdl-35031858
ABSTRACT
GRIA3 at Xq25 encodes glutamate ionotropic receptor AMPA type 3 (GluA3), a subunit of postsynaptic glutamate-gated ion channels mediating neurotransmission. Hemizygous loss-of-function (LOF) variants in GRIA3 cause a neurodevelopmental disorder (NDD) in male individuals. Here, we report a gain-of-function (GOF) variant at GRIA3 in a male patient. We identified a hemizygous de novo missense variant in GRIA3 in a boy with an NDD c.1844C > T (p.Ala615Val) using whole-exome sequencing. His neurological signs, such as hypertonia and hyperreflexia, were opposite to those in previous cases having LOF GRIA3 variants. His seizures and hypertonia were ameliorated by carbamazepine, inhibiting glutamate release from presynapses. Patch-clamp recordings showed that the human GluA3 mutant (p.Ala615Val) had slower desensitization and deactivation kinetics. A fly line expressing a human GluA3 mutant possessing our variant and the Lurcher variant, which makes ion channels leaky, showed developmental defects, while one expressing a mutant possessing either of them did not. Collectively, these results suggest that p.Ala615Val has GOF effects. GRIA3 GOF variants may cause an NDD phenotype distinctive from that of LOF variants, and drugs suppressing glutamatergic neurotransmission may ameliorate this phenotype. This study should help in refining the clinical management of GRIA3-related NDDs.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Carbamazepina
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Receptores de AMPA
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Antagonistas de Aminoácidos Excitatórios
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Transtornos do Neurodesenvolvimento
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Mutação com Ganho de Função
Tipo de estudo:
Prognostic_studies
Limite:
Animals
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Child, preschool
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Humans
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Male
Idioma:
En
Revista:
Hum Genet
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
Japão