Epilepsy and movement disorders are found together in many clinical syndromes and a link at a molecular level is being increasingly recognized by the cloning of genes responsible for these conditions. Further evidence for the molecular overlap of movement disorders and epilepsy comes from genes cloned in mutant mice.

There are two major groups of disorders causing both movement disorders and epilepsy: neurodegenerative disorders and channelopathies.

In this chapter we will briefly review neurodegenerative conditions in which epilepsy and movement disorders are the predominant symptoms. The second part of this chapter will deal with the developing field of channelopathies. Over the past few years, several ion channel genes have been implicated in idiopathic epilepsy and paroxysmal movement disorders. In addition, the cloning of ion channels as the genes responsible for mouse mutants with epilepsy and movement disorders and the creation of mouse knockouts of specific genes, have emphasized the importance of this group of genes in the pathogenesis of these disorders.

Neurodegenerative disorders

Many neurodegenerative conditions have either epilepsy, or a movement disorder or both as a manifestation of disease in some individuals. In this chapter however, we will describe the genetic abnormalities in three diseases in which both epilepsy and movement disorders are prominent components of the phenotype.

Mitochondrial cytopathies

Mitochondrial disease is frequently associated with epilepsy, either generalized tonic-clonic events or myoclonic epilepsy.