Different variants in the KCNC1 gene have been associated with various neurological conditions. Depending on the gene variant, the KCNC1-related symptoms can vary from very severe to mild.
Main clinical features:
Different disease-causing variants in KCNC1 have been described to cause diverse neurological disorders including progressive myoclonus epilepsy with ataxia (MEAK-Syndrome; Myoclonus and Ataxia due to Potassium channel mutation), non-progressive myoclonus alone, intellectual disability, and developmental and epileptic encephalopathy with myoclonic, absence and generalized seizures – see clinical characteristics.
Inheritance:
KCNC1-related disorder is inherited in an autosomal dominant manner. In the vast majority, the disease-causing variant was found de novo in the affected patients, and the pathogenic variant was not detected in the unaffected parents. Both maternal and paternal inheritance from affected parents (Muona et al., 2015; Poirier et al., 2017) as well as germline mosaicism have been reported (Kim et al, 2018) – see molecular characteristics.
KCNC1