Abstract
Juvenile myoclonic epilepsy (JME) is the most frequent cause of hereditary grand mal seizures1,2. We previously mapped and narrowed a region associated with JME on chromosome 6p12–p11 (EJM1)3,4,5. Here, we describe a new gene in this region, EFHC1, which encodes a protein with an EF-hand motif. Mutation analyses identified five missense mutations in EFHC1 that cosegregated with epilepsy or EEG polyspike wave in affected members of six unrelated families with JME and did not occur in 382 control individuals. Overexpression of EFHC1 in mouse hippocampal primary culture neurons induced apoptosis that was significantly lowered by the mutations. Apoptosis was specifically suppressed by SNX-482, an antagonist of R-type voltage-dependent Ca2+ channel (Cav2.3). EFHC1 and Cav2.3 immunomaterials overlapped in mouse brain, and EFHC1 coimmunoprecipitated with the Cav2.3 C terminus. In patch-clamp analysis, EFHC1 specifically increased R-type Ca2+ currents that were reversed by the mutations associated with JME.
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Acknowledgements
We thank the family members for participating in this study; Y. Itsukaichi, K. Yamada, Y. Tsutsumi, K. Shoda, E. Mazaki, A. Nitta, N. Okamura, C. Uchikawa, M. Hishinuma and S.G. Pietsch for their help; and the Research Resources Center of RIKEN Brain Science Institute for DNA sequencing analysis and generation of rabbit polyclonal antibodies. This work was supported in part by a grant from RIKEN Brain Science Institute, Japan. A.V.D.E. is partly supported by a grant from the US National Institutes of Health.
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Supplementary information
Supplementary Fig. 1
Amino acid sequence of EFHC1 and evolutionary conservation of amino acids mutated in JME. (PDF 25 kb)
Supplementary Fig. 2
Expression of mouse Efhc1 transcripts and proteins. (PDF 500 kb)
Supplementary Fig. 3
No effect of VDCC antagonists on neurons expressing GFP-controls and binding of EFHC1 mutants to CaV2.3. (PDF 642 kb)
Supplementary Table 1
Modulation of activation and inactivation properties of CaV2.3 by EFH1 proteins. (PDF 397 kb)
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Suzuki, T., Delgado-Escueta, A., Aguan, K. et al. Mutations in EFHC1 cause juvenile myoclonic epilepsy. Nat Genet 36, 842–849 (2004). https://doi.org/10.1038/ng1393
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DOI: https://doi.org/10.1038/ng1393
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