A new study has found that an autosomal dominantly inherited mutation in the SCN4A gene is associated with essential tremor and increased susceptibility to epilepsy in a large Spanish family. SCN4A encodes the voltage-gated sodium channel NaV1.4, which was previously thought to be confined to muscle, but the researchers were able to detect SCN4A mRNA in neuronal tissue. The results point towards neurological channelopathies as one of the underlying causes of essential tremor.