Study On The Hot Spot Mutation Of SLC26A4 Gene And LVAS In Sensorineural Hearing Loss With Unknown Reason

Objective: Study the incidence of large vestibular aqueduct syndrome(LVAS) and the hot spot mutation of SLC26A4 (solute carrier family 26,member 4 gene) in sensorineural hearing loss with unknown reason. Show the clinical significance to detect this hot spot mutation: SLC26A4 IVS7-2 A>GMethods: 95 cases of sensorineural hearing loss with unknown reason and 90 control individuals with normal hearing were included in this study. 2ml peripheral blood was taken from all subjects to extract gDNA with the phenol-chloroform method. The gene fragment which included SLC26A4 IVS7-2 A>G was amplified by polymerase chain reaction and analyzed by directly DNA sequencing. The individuals with homozygous or heterozygous SLC26A4 IVS7-2 A>G were given further temporal bone CT scan. The results of SLC26A4 genetic detection and temporal bone CT scan were compared with each other.Results:In the deafness group, 24 cases carried the SLC26A4 IVS7-2 A>G, of whom 6 cases were homozygous mutation and 18 cases were heterozygous mutation.. No one in the control group carried this mutation. The incidence of the mutation is significantly different between the two groups(x~2test, P<0.001). All the 24 cases were given temporal bone CT scan. The 6 cases carrying homozygous mutation were confirmed to be LVAS by CT scan and 15 of the 18 cases carrying heterozygous mutation were LVAS. So, the gene diagnosis is in conformity to the clinical one(6/6). The incidence of LVAS in the heterozygous mutation carriers is 83.33%(15/18). In the group of sensorineural hearing loss with unknown reason, the incidence of LVAS which correlates with SLC26A4 IVS 7-2 A>G is 22.11%(21/29).Conclusion: There is a high incidence of SLC26A4 IVS7-2 A>G and LVAS in the sensorineural hearing loss with unknown reason. The patients carrying homozygous mutation can be accurately confirmed to be LVAS. It is suggested to utilize this detection for genetic counseling, prenatal diagnosis, and the genetic screening of neonates and the sensorineural hearing loss with unknown reason.