Expansions of intronic TTTCA and TTTTA repeats in benign adult familial myoclonic epilepsy
- PMID: 29507423
- DOI: 10.1038/s41588-018-0067-2
Expansions of intronic TTTCA and TTTTA repeats in benign adult familial myoclonic epilepsy
Abstract
Epilepsy is a common neurological disorder, and mutations in genes encoding ion channels or neurotransmitter receptors are frequent causes of monogenic forms of epilepsy. Here we show that abnormal expansions of TTTCA and TTTTA repeats in intron 4 of SAMD12 cause benign adult familial myoclonic epilepsy (BAFME). Single-molecule, real-time sequencing of BAC clones and nanopore sequencing of genomic DNA identified two repeat configurations in SAMD12. Intriguingly, in two families with a clinical diagnosis of BAFME in which no repeat expansions in SAMD12 were observed, we identified similar expansions of TTTCA and TTTTA repeats in introns of TNRC6A and RAPGEF2, indicating that expansions of the same repeat motifs are involved in the pathogenesis of BAFME regardless of the genes in which the expanded repeats are located. This discovery that expansions of noncoding repeats lead to neuronal dysfunction responsible for myoclonic tremor and epilepsy extends the understanding of diseases with such repeat expansion.
Comment in
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Epilepsy: A role for expanded DNA repeats in familial epilepsy.Nat Rev Neurol. 2018 May;14(5):251. doi: 10.1038/nrneurol.2018.37. Epub 2018 Mar 23. Nat Rev Neurol. 2018. PMID: 29569625 No abstract available.
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Repeat expansions in myoclonic epilepsy.Nat Genet. 2018 Apr;50(4):477-478. doi: 10.1038/s41588-018-0093-0. Nat Genet. 2018. PMID: 29632377 No abstract available.
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The Key to FAME: Intronic Repeat Expansions Cause Human Epilepsies.Epilepsy Curr. 2018 Jul-Aug;18(4):238-239. doi: 10.5698/1535-7597.18.4.238. Epilepsy Curr. 2018. PMID: 30254519 Free PMC article. No abstract available.
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