A novel developmental encephalopathy with epilepsy and hyperkinetic movement disorders associated with a deletion of the sodium channel gene cluster on chromosome 2q24.3

We reported a 21 months-old boy with a complex epilepsy phenotype, developmental delay, and hyperkinetic movement disorders, associated with a deletion of the whole sodium channel gene cluster. Whether this unusual phenotype results from leading to haploinsufficiency of either SCN1A or SCN2A, or the combination of both, remains subject of speculation. However, nobody of the numerous reported patients with truncating mutations in SCN1A has ever manifested such a clinical phenotype