[en] Temple-Baraitser syndrome (TBS) is a multisystem developmental disorder characterized by intellectual disability, epilepsy, and hypoplasia or aplasia of the nails of the thumb and great toe. Here we report damaging de novo mutations in KCNH1 (encoding a protein called ether a go-go, EAG1 or KV10.1), a voltage-gated potassium channel that is predominantly expressed in the central nervous system (CNS), in six individuals with TBS. Characterization of the mutant channels in both Xenopus laevis oocytes and human HEK293T cells showed a decreased threshold of activation and delayed deactivation, demonstrating that TBS-associated KCNH1 mutations lead to deleterious gain of function. Consistent with this result, we find that two mothers of children with TBS, who have epilepsy but are otherwise healthy, are low-level (10% and 27%) mosaic carriers of pathogenic KCNH1 mutations. Consistent with recent reports, this finding demonstrates that the etiology of many unresolved CNS disorders, including epilepsies, might be explained by pathogenic mosaic mutations.
Disciplines :
Genetics & genetic processes
Author, co-author :
Simons, Cas
Rash, Lachlan D.
Crawford, Joanna
Ma, Linlin
Cristofori-Armstrong, Ben
Miller, David
Ru, Kelin
Baillie, Gregory J.
Alanay, Yasemin
JACQUINET, Adeline ; Centre Hospitalier Universitaire de Liège - CHU > Génétique
Debray, François-Guillaume ; Université de Liège - ULiège > Département des sciences biomédicales et précliniques > Maladies métaboliques d'origine génétique
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