OBJECTIVETo describe clinical and genetic feature in a Chinese family with familial idiopathic basal ganglia calcification 3 (IBGC-3) caused by a novel mutation in the SLC20A2 gene.

METHODSClinical data was collected from a family with familial IBGC-3. All of the family members underwent cerebral CT. Potential mutation of the SLC20A2 gene were screened in the proband, 5 symptomatic patients, 5 asymptomatic family members, and 100 healthy Chinese controls. Exon 8 of the SLC20A2 gene was cloned into plasmid and sequenced.

RESULTSThere were 6 symptomatic patients (3 males and 3 females) in an autosomal dominant pedigree. The patients manifested as juvenile-onset paroxysmal kinesigenic dyskinesia, in addition to pyramidal signs in proband. 5 patients alive had calcification in bilateral basal ganglia and subcortical areas. One asymptomatic member also had calcification in the brain; and 2 cases of asymptomatic young members had bilateral globus pallidus calcification. A novel c.1086delC mutation in SLC20A2 gene has been identified in proband and 7 family members with intracranial calcification. The deletion mutation was not found in 2 family members without intracranial calcification and healthy controls members. There is no clear relationship between clinical symptoms and the severity of calcification in cerebral CT.

CONCLUSIONFamilial idiopathic basal ganglia calcification caused by the SLC20A2 gene mutation can manifest as juvenile onset paroxysmal kinesigenic dyskinesia. Further study should be done to validate the unrelated relationships between the severity of calcification in IBGC 3 cranial CT and clinical symptoms.