KCNQ2 epileptic encephalopathy

Genetics and pathology

• This is caused by mutations in the KCNQ2 gene
• KCNQ2 encodes the potassium channel subunits underlying the M-current
• Some cases are associated with STXBP1 epileptic encephalopthy
• The transmission is autosomal dominant

Clinical features

Electroencephalogram (EEG): features

Magnetic resonance imaging (MRI)

Differential diagnosis

Complications

First line treatments: sodium channel blocking drugs

Second line treatments

References

1. Soldovieri MV, Cilio MR, Miceli F, et al. Atypical gating of M-type potassium channels conferred by mutations in uncharged residues in the S4 region of KCNQ2 causing benign familial neonatal convulsions. J Neurosci 2007; 27:4919-4928.
2. Borgatti R, Zucca C, Cavallini A, et al. A novel mutation in KCNQ2 associated with BFNC, drug resistant epilepsy, and mental retardation. Neurology 2004; 63:57-65.
3. Steinlein OK, Conrad C, Weidner B. Benign familial neonatal convulsions: always benign? Epilepsy Res 2007; 73:245-249. 
4. Soldovieri MV, Boutry-Kryza N, Milh M, et al. Novel KCNQ2 and KCNQ3 mutations in a large cohort of families with benign neonatal epilepsy: first evidence for an altered channel regulation by syntaxin-1A. Hum Mutat 2014; 35:356-367. 
5. Devaux J, Dhifallah S, De Maria M, et al. A possible link between KCNQ2- and STXBP1-related encephalopathies: STXBP1 reduces the inhibitory impact of syntaxin-1A on M current. Epilepsia 2017; 58:2073-2084. 
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Related checklists

• KCNQ2 benign familial neonatal convulsions (BFNC)
• KCNQ2 variant manifestations