Screening The Mutation Of CHN1in Sporadic Duane Retraction Syndrome In Chinese Population

Objective To study wether the sporadic Duane retraction syndrome (DRS) in Chinese population existing the known mutation loci of CHN1, and to investigate the genetic heterogeneity in different ethnic groups and the pathogenesis of DRS.Method Patients diagnosed as DRS in the Affiliated Hospital of Qingdao University during2010-2013were collected and were classified as case group.1. Clinical study Medical history, family history, ophthalmic examinations and strabismus specialist examinations of the patients were recorded and analyzed.2. Genetic study Venous blood samples (10ml) from the patients and the healthy volunteers (control group) were collected. And genomic DNA was extracted from peripheral leukocytes. Polymerase chain reaction (PCR) was used to amplified the genes in the known mutation loci of CHNl.Then the agarose gel electrophoresis (AGE) was used to detect the PCR products, finally the products were sent to directly sequence. The results of sequencing were analyzed and were compared with the normal control in order to determine whether it was disease causing mutation or not.Results1.14DRS (15eyes) sporadic patients with negative family history were collected, including4male and10female. And11patients were type I,1was type Ⅱ,2were type Ⅲ. They all had unilateral DRS except1patient with bilateral DRS. All patients had compensatory head position.2. No mutations were detected in any of the14sporadic DRS patients.Conclusion1. Clinical characteristic:the type I DRS was the most common type in the14sporadic patients, and unilateral patients were more common than bilateral patients. Female patients were more common.2. Genetic characteristic:(1) The known mutations of CHN1founded in familial DRS patients were not the disease causing mutations in the14sporadic DRS patients, which were same with the results of other researches that CHN1were not the common cause for sporadic DRS.(2) CHN1may not the disease causing gene for sporadic DRS patients of Chinese population, and the disease causing gene leading to sporadic DRS and familial DRS may be different. There may be many genes leading to DRS and a large scale research were needed to determine the disease causing gene for sporadic DRS.