Analysis Of The Relatoin Between Gene Mutation And Clinical Phenotype For Autosomal Recessive Families

Objetive:To detect the gene mutation of GJB2 and SLC26A4 gene in 29 autosomal recessive families, and to analyze the relationship between clinical phenotype and gene mutation.Meanwhile,to to approach to clinical significance and contribution of the hot spot for the genes.Methods:Collected the clinical datas of 42 patients.Pure tone audiometry,acoustic impedance and auditory brainstem response were used to examine the patients.The GJB2 and SLC26A4 exon7+8,exon10,exon19 of 42 patients and some of their parents,as well as 105 persons of normal control were amplified by polymerase chain reaction(PCR).Then the PCR products were subjected to automatic DNA sequencing.Results:235de1C,176del16bp,109G＞A,79G＞A,341A＞G and 608T＞C were detected in GJB2. 235delC homozygous mutation,a frameshift mutation was detected in two patients.One patient was Sensorineural Hearing Loss while another patient was Mixed Hearing Loss. 176del16bp heterozygous mutation was detected in twins who were Mixed Hearing Loss. 109G→A,79G→A and 341A→G mutations were occurred in both patients and control group. 608T＞C only appeared in a patient.IVS7-2A＞G and T410M were detected in hot spot of SLC26A4.IVS7-2A＞G homozygous mutation was detected in patient who was Sensorineural.IVS7-2A＞G heterozygous mutation was detected in two patients.T410M heterozygous mutation was also detected in one of the patients who was Sensorineural Hearing Loss. Conclusion:235delC homozygous mutation is one of pathogenic mutations of GJB2 which could appear in patients with Sensorineural Hearing Loss as well as Mixed Hearing Loss.176del16bp heterozygous mutation combine with environmental factor may cause hearing loss.109G＞A, 79G＞A,341A＞G and 608T＞C were considered to be polymorphism of GJB2.IVST-2A＞G homozygous mutation is one of pathogenic mutations of SLC26A4. IVS7-2A＞G heterozygous mutation combine with T410M heterozygous mutation cause hearing loss.The incidence of SLC26A4 is inferior to GJB2 in autosomal recessive hearing loss.