Loss of the calcium channel β4 subunit causes motor impairment (Khan & Jinnah, 2002) with striking similarities between the lethargic (β4−/−) mouse and mouse models with Cav2.1‐related forms of ataxia (Fletcher et al., 1996; Burgess & Noebels, 1999a,b; Barclay et al., 2001; Guida et al., 2001; Pietrobon, 2002). The gene discussed is CACNA1A; the disease is cerebellar ataxia.