Clinical Investigation Of A Huge Family With Autosomal Dominant Hereditary Non-syndromic Hearing Loss

The incidence of congenital hearing loss is estimated at 1 in 1000 births, ofwhich approximately equal numbers of cases are attributed to environmental andgenetic factors. The hearing-loss disorders which are attributable to genetic causesare classified as nonsyndromic and syndromic deafness. The total number of genesinvolved in nonsyndromic hereditary deafness has been estimated to above 100, Inour research, we will analyze the auditory data and genetic characteristicscollected from a huge family with aotosomal dominant hereditary non-syndromichearing loss in Jilin of China. The full collections of both blood samples andphysiological hearing assessments of this family have provided the solid basis forfuture study on identifying disease causing gene1. Data and method1.1 collection and mathod: In this family, some Individuals in this familyhave been conducted physical examination, asking of disease history including age,development, degree, drug, contaction to yawp, pus of ears, tinnitus, giddy,parotitis, measles, scarlatina, intermarriage, et al.1.2 physical examination: response to environments, expression,intelligence and malformation correlating to syndrome such as hair, skin, eyelid,sclera, jaw, vertebral column, extremity, et al.1.3 examination of otology: including malformation of middle ear and outer ear.1.4 Audiological ExaminationStandard air-and bone-conduction pure-tone audiometry (250-8000Hz) wasadministered in all patients using the MADSEN ORBITER 922 audiometer, whichwas calibrated to International Organzation for Standarization (ISO). AcousticImmittance measurement were tested using the MADSEN ZODIAC 901. Testtones ranged from 0.125 to 8 kHz. ABR were tested using the DANTECEVOLUTION. Aforementioned examinations ipsilateral or contralateral to checkear (or both) were measured. Reflex was considered absent when no reflex couldbe induced at test intensities up to and including 120dB HL. 2. Result 2.1 Pedigree Analysis Eight generations in pedigree were investigated. 1.Pedigree analysis indicated that patients distributed five continuous generations 2.one of the parents was the patient 3. In this pedigree, there are 688 individual, 33patients in 323 female, about 10.2%, and 41 patients in 365 male about 11.2%. 2.2 Age and symptom: Eight generations 688 person in pedigree wereinvestigated in the present study, but there are other person in this pedigree whichwas not been investigated, we will supplement it. In this pedigree, 74 person werediagnosed, 11 suffered prelinguistic severe nervous hereditary deafness anddeafmutism, 63 suffered postlingual nervous hereditary deafness before 30 yearsold, and have the ability of language, and no associated visible abnormalities inother systems were found in this family. 2.4 Audiological Examination Data 2.4.1 the pure tone audiometry: 74 person were diagnosed the hearings lossand the pure tone audiometry showed that the hearing loss was nervous deafnessand in all frequencies. The patients who suffered Severe Hearing Loss were most. 2.4.2 Acoustic immitance: A tape curve in both sides. in the prohand V190,V191, IV89, IV90, IV94, the results of ABR and the pure tone audiometry showedthat the hearing loss was nervous deafness 2.5 other test: HRCT of temporal bone of V191,IV94 showed the normalinner ears. chromosome analysis of V191 showed 46, XX 3. discussion The patients in this predigree in the present study displayed strikingly similarfeatures. However, they lived with the local residents who did not represent thesame symptom of deafness. So, we can eliminate the possibility of environment. Inthe physical examination, the patients who suffered from hearing loss all had notanother disorder, we can exclude syndromic deafness. Based on these Genetic characters, this predigree was considered as one ofauotsomal dominant inheritance The medical history and auditory analysis of the members of this pedigreeshow that this pedigree is a family with nonsyndromic autosomal dominantnervous hereditary deafness. There is possibility that the gene of this hereditarydeafness is the gene which has been mapped. The happen and development of the deafness can not be the warrant of thediagnoses, the pedigree analysis and genes mapping shuld be done at the sametime. Go in studies of the molecular genetics of hearing and deafness, more insightmay be gained into the molecular process of hearing and the pathology of hearingloss. Functional studies of deafness genes will lead to a more fundamental andthorough understanding of the happen, development, and explain the mechanismof the hereditary deafness in molecular level and map the mutated genes in orderto diagnose and therapy with the hereditary deafness .The full collections of bothblood samples and physiological hearing assessments of this family have providedthe solid basis for future study on identifying disease causing gene. 4. conclusion In the present study, we found a chinese hereditary deafness pedigree. The...