An exome sequencing study of 197 unrelated patients with developmental and epileptic encephalopathy identified four patients with a similar phenotype and a Tyr433Cys (Tyr434Cys in human nomenclature) de novo point mutation in the TRKB gene, in the very same tyrosine residue that has been mutated to phenylalanine in our studies (Hamdan et al. 2017). The gene discussed is NTRK2; the disease is Epileptic encephalopathy.