Familial hemiplegic migraine (FHM) can be loosely divided into two categories: with and without cerebellar signs. Cerebellar signs refer to ataxia, sometimes episodic and other times progressive, that can accompany FHM1 mutations and is caused by degeneration of the cerebellum.
Familial hemiplegic migraine (FHM) is categorized into two groups: those with cerebellar symptoms and those without. Cerebellar signs include ataxia, which can be episodic or progressive, and are caused by FHM1 mutations. This ataxia results from damage to the cerebellum.