ABSTRACT
Objective To learn the situation of deafness gene among deaf children and to provide suggestions for intervention.Methods Twenty hot spot mutations of the common deafness genes of GJB2,GJB3,MT -RNR1,SLC26A4 for 93 deafness patients were detected by MALDI -TOF -MS,and Sanger sequencing method was used to detect the whole exon of the gene for the heterozygous mutant.Results A total of 48 cases were detected with mutation among the 93 patients using MALDI -TOF -MS,and the detection rate was 51.61%.Thirty five cases were GJB2 mutation,and the detection rate was 37.63%,in which 24 cases were homozygous mutation or compound heterozygous mutations and 11 cases were heterozygous mutation.Thirteen cases were SLC26A4 mutation,and the detection rate was 13.98%,in which 6 cases were homozygous mutation or compound heterozygous mutations and 7 cases were single heterozygous mutation.Mutation in MT -RNR1 and GJB3 gene were not detected.Among the 18 mutation cases,17 cases were detected the whole exon of the gene with mutation using Sanger sequencing,and 12 cases were detected other loci heterozygous mutation (70.59%).And a total of 42 cases were found out the cause of the deafness,and the detection rate was 45.16%.Conclusion The mutation of the common deafness gene in patients with deafness in the region has a high detection rate.The whole exon of the gene with mutation was detected,which can improve the detection rate of the cause of deafness.
ABSTRACT
Objective To learn the detection rate of deafness predisposing genes among newborns in order to provide suggestions for the prevention of hereditary hearing loss.Methods By means of MALDI -TOF,a total of 4 025 newborns were accepted for newborn hearing and deafness predisposing genetic screening.Four common deafness predisposing genes including GJB2,GJB3,12SrRNA and SLC26A4 were detected,which included 20 hot mutation sites.Results Of the 4 025 subjects,231 were detected with deafness predisposing genes and the positive rate was 5.71%.The total rate of pathogenic mutation was 1.74‰(7 /4 025),including 1 with GJB2 235delC homozygous mutation,1 with GJB2 235delC heterozygous mutation plus 299_300 del AT heterozygous mutation and 5 with 12SrRNA homozygous mutation.The positive rate of single heterozygous mutation was 5.54% (223 /4 025).Fourteen hot mutation sites were detected.GJB2 235delC was the most common one,followed by IVS7 -2A→G.There were 109 cases with GJB2 235delC and 50 cases with IVS7-2A→G.The positive rate was 2.71% and 1.24% respectively,which was 47.19% and 21.65% of the total detection rate respectively.Conclusion The detection rate of deafness predisposing genes is high among newborns.Expanding screening sites could facilitate the detection for the carrier of deafness gene.
ABSTRACT
Objective To evaluate the effectiveness of newborn screening of hearing combined with deafness predisposing genes. Methods Through screening,514 newborns who may had the problem of hearing were classified as experimental group and the other 1 028 newborns were classified as control group by MALDI-TOF. Detecting the predisposing genes of GJB2,GJB3,12SrRNA,SLC26A4 including 20 hot spot mutations for these newborns. Results Among 514 subjects, 40 cases were found with deafness gene mutations,and the positive rate was 7. 47%. 7 cases were pathogenic mutation(1 was GJB2 235delC homozygous mutation,6 were GJB3 538C→T heterozygous mutation ),with the rate of 1. 36%,and 33 cases were heterozygous carrier,with the rate of 6. 62%. Among the control group,45 cases were found with deafness gene mutations,and the positive rate was 4. 38%. 3 cases were pathogenic mutation(1 was 12srRNA 1555A→G homozygous mutation,1 was GJB3 538C→T heterozygous mutation,1 was GJB3 547G→A heterozygous mutation),with the rate of 0. 29%,and 42 cases were carriers of heterozygous gene,with the rate of 4. 09%. The positive rate,the pathogenic mutation rate and the heterozygous carry rate of experimental group were higher than that of control group ,and the differences were significant(all p<0. 05). Conclusion The newborns who did not pass the hearing screening should be the target population for test of the deafness predisposing genes. Since the positive rate were still high,if condition permitted,the screening of hearing combined with deafness predisposing genes should be carried out in some areas.