Autosomal recessive epilepsy associated with contactin 2 mutation is different from familial cortical tremor, myoclonus and epilepsy

ARTICLE Sir, In a recent interesting paper, Stogmann et al. (2013) described a consanguineous Egyptian family with autosomal recessively inherited condition featuring focal epilepsy, neuropsychiatric features, borderline cognitive level, and myoclonus. Exome sequencing in this family revealed a homozygous deletion (c.503_503delG) leading to a frameshift in the coding region of CNTN2 and segregating in the five affected family members. The gene CNTN2 encodes for contactin 2, a glycosylphosphatidylinositol-anchored neuronal membrane protein, necessary to maintain voltage-gated potassium channels at the juxtaparanodal region. Given the severity of the mutation and the function of the protein, the authors considered this mutation as the most likely cause of the clinical phenotype in this family (Stogmann et al. , 2013). However, we would recommend caution when describing this family as affected by ‘familial …