OBJECTIVETo explore the feasibility of using PCR-based capillary electrophoresis method to analysis mutation of the TOR1A gene in a family affected with primary torsion dystonia (PTD).

METHODSPeripheral blood sample was collected from proband and amnionic fluid from her fetus for the extraction of DNA. The 5th exon of the TOR1A gene and its flanking sequences were amplified with PCR and analyzed with agarose electrophoresis, fluorescence labeled fragment analysis and Sanger sequencing.

RESULTSFluorescence labeled fragment analysis was performed through capillary electrophoresis, which showed that the proband carried a c.907_909delGAG (p.Glu303del) deletional mutation of the TOR1A gene. The result was verified by Sanger sequencing. The fetus DNA was also found with the same mutation by capillary electrophoresis, inferring that the fetus was probably affected with the disease.

CONCLUSIONThe mutation of c.907_909delGAG of the TOR1A gene was speculated as pathologic cause of proband in this family. Fragment analysis by capillary electrophoresis combined with DNA sequencing is an efficient test for small deletional mutations and feasible for its prenatal diagnosis.