Brain & development
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Brain & development · May 2018
Case ReportsFamilial cases of progressive myoclonic epilepsy caused by maternal somatic mosaicism of a recurrent KCNC1 p.Arg320His mutation.
A recurrent de novo mutation in KCNC1 (c.959G > A, p.Arg320His) has been identified recently as one of the important genetic causes of progress myoclonic epilepsy (PME). The clinical phenotype resulting from this mutation has been named as myoclonus epilepsy and ataxia due to potassium channel mutation (MEAK). This finding carries important clinical implications in that autosomal dominant inheritance and de novo occurrence need to be considered when conducting genetic tests in patients with PME. We present two familial cases of MEAK in siblings with a recurrent p.Arg320His mutation in KCNC1. ⋯ Our familial MEAK cases show that consideration of parental mosaicism in addition to meticulous phenotyping is needed when conducting KCNC1 genetic testing.