Mapping And Identification Of The Causative Genes In Three Chinese Pedigrees With Autosomal Dominant Hereditary Hearing Loss

Objective:We investigated three pedigrees with hereditary deafness(named HBSY-012?HBSY-013 and HBSY-014).Analyze the audiological and genetic characteristics of these families,and identify the causative gene.Methods:Detailed medical history,analysis of deafness phenotype and mode of inheritance,extracting peripheral blood DNA of family members;At first,using target gene enrichment and massively parallel sequencing(TGE+MPS)technology,three families of probands were screened for known deafness genes(including 153 nuclear genes,6 mitochondrial genes and 3 microRNAs);Initial screening does not clearly explain the cause of the disease,according to pedigree characteristics,the HBSY-012 family was linked by linkage analysis and whole exome sequencing,while the HBSY-013 and HBSY-014 families were further searched for disease-causing genes using a simple exome sequencing method.Then,Sanger sequencing was used for co-segregation of clinical phenotypes and genotypes for suspicious pathogenic sites.Results:1?In the family of HBSY-012,the family 5 generations live in Guangshan county,Henan Province,in which 34 members in 3 generations were alive,through hearing tests,14 were diagnosed as sensorineural deafness;Pedigree tree shows the family with the typical autosomal dominant genetic model,the age of onset in the 5-7 years old,show post-lingual sensorineural hearing loss.No pathogenic mutations were found by known deafness genes.By linkage analysis,the causative gene was located in the q31.1-q31.3 segment of the long arm of chromosome 9(maximum LOD value of 3.6076),temporarily named the site DFNA74,focusing on this segment of WES results.And outside the section,EVI5 c.2399C>T,ANKMY2 c.822 826del,DDX49 c.341C>T and DEFB129 c.284G>T were verified in the family,but no co-segregation occurred in the family.2?In the family of HBSY-013,5 generations live in Pingdingshan City,Henan Province,There were 4 generations,40 in total,and 8 families were diagnosed as sensorineural deafness.The pedigree maps showed that the model was basically consistent with the autosomal dominant inheritance pattem.Deafness phenotype is characterized by post-lingual,and the age of onset is between 16 and 25 years old.No known pathogenic mutations have been found in deafness gene screening;two family members have been selected to perform full exome sequencing,and sequencing results have not yet been analyzed.3.In the family of HBSY-014,5 generations live in Jianli County,Hubei Province,There were 39 people in 4 generations.Five family members were diagnosed as sensorineural deafness.The pedigree showed that the model was basically in accordance with the autosomal dominant inheritance pattern.It is characterized by post-lingualism,and the onset age is between 6 and 40 years old.No known pathogenic mutations have been found in deafness gene screening,two family members have been selected for full exome sequencing,sequencing results have not yet been analyzedConclusion:1.All three family members of deafness are non-syndromic autosomal dominant deafness families;2.No pathogenic mutations were found by known deafness genes;3.In the HBSY-012 pedigree,the pathogenic gene was located in the q31.1-q31.3 segment of the long arm of chromosome 9 by linkage analysis(maximum LOD value of 3.6076),which is the new deafness locus,its location is temporarily Named DFNA74,no pathogenic genes were found in WES,pathogenic mutations were considered in non-coding regions.4?In the HBSY-013 pedigree,WES has obtained preliminary analysis results,after expanding the sample size,complete family co-separation research work;5?In the HBSY-014 pedigree,WES has obtained preliminary analysis results,need to complete family co-separation research work.