Correlating the clinical and genetic features of benign familial neonatal seizures (BFNS) with the functional consequences of underlying mutations.

Almost ten years have passed since the identification of Kv7.2 and Kv7.3, the genes altered in benign familial neonatal seizures (BFNS), a familial autosomal dominant focal epilepsy of the newborn. Despite the rarity of the disease, clinical and genetic data have been gathered from more than 50 BFNS-affected families; these studies reveal that each family harbours a specific disease-causing mutation, and that the mutation-induced functional changes range from a subtle alteration in channel behaviour to a complete ablation of channel function. Prompted by the recent identification of peculiar gating changes in Kv7.2 subunits caused by novel mutations responsible for BFNS, in the present work we attempt to link, whenever possible, the specific genetic defect with the clinical evolution of the disease in the affected families on one side, and, on the other, with the functional defects revealed by expression studies. Such genotype-phenotype correlations may provide clues on the pathogenesis of the wide variety of neuropsychiatric manifestations often associated to BFNS, and should foster our attempts to gain more detailed functional information which might help to elucidate the pathogenetic mechanisms of the disease.