microtubule-associated protein (MAP) that is abundant in sperm flagella and motile cilia but expressed at low levels in the adult brain. It is not present in immotile primary cilia. May enhance calcium influx through CACNA1E and stimulate programmed cell death. Interacts with the C-terminus of CACNA1E. Implicated in neuronal migration and may play a role during brain development. Mutations in EFHC1 gene have been previously reported in patients with epilepsies, including those with juvenile myoclonic epilepsy. Two alternatively spliced human isoforms have been described. Note: This description may include information from UniProtKB.