OBJECTIVETo analyze the mutations in a pedigree with maternally inherited sensorineural hearing loss, and to investigate whether 235delC heterozygote mutation in gap junction protein beta 2 (GJB2) gene modulates the severity of hearing loss associated with the A1555G mitochondrial mutation.

METHODSThe PCR products were digested with the Alw26 I restriction enzyme, followed by direct sequencing to detect the mitochondrial mutations in 72 members of a core pedigree of an extensive family with matrilineal nonsyndromic deafness; 235delC mutation of the GJB2 gene was screened in this family by using the Apa I restriction enzyme and direct sequencing.

RESULTSThe A1555G mutation of the mitochondrial DNA was present in all 27 members of maternal line, out of them, 21 members had phenotype of deafness (77.8%), with a high penetrance. Only three maternal line members of 72 members possessed 235delC heterozygote mutations, and the three had different phenotypes.

CONCLUSIONThe A1555G homozygous mutation of mitochondrial DNA is the susceptive etiological factor of nonsyndromic deafness in this family, but in the study of this pedigree, the 235delC heterozygous mutation in GJB2 gene may not aggravate the symptoms of hearing loss associated with the A1555G mitochondrial mutation.

Base Sequence ; Connexin 26 ; Connexins ; genetics ; DNA Mutational Analysis ; DNA, Mitochondrial ; chemistry ; genetics ; Female ; Hearing Loss, Sensorineural ; genetics ; Heterozygote ; Humans ; Male ; Mutation ; Pedigree ; Polymerase Chain Reaction

Objective To investigate the prevalence of thyroid nodules(TN)among centenarians in Hainan province and explore the association between thyroid nodules and major chronic diseases.Methods A mixed cross-sectional study of questionnaire survey,medical examination including ultrasonography and laboratory examination were conducted in elderly who resided in Hainan province and aged 100 and over,the subjects who have signed consent and complete data in both basic information and medical examination were included in this study.Eight hundred and four centenarians were finally enrolled and data of them was analyzed to investigate the prevalence of thyroid nodules and to explore its association with common chronic diseases by comparing the prevalence of chronic conditions between groups with and without thyroid nodules.Results The overall prevalence of TN was 73.5%(591、804)and the prevalence of TN was significantly higher in female when comparing with male[75.1%(505、672)vs 65.2%(86、132)](P <0.001).No significant correlation was found between the prevalence of TN and major chronic diseases (P>0.05),however,the factors associated with dyslipidemia and anemia such as TC[(4.6±1.2)mmol、L vs(4.3±1.5)mmol、L],LDL-C[(2.8±0.8)mmol、L vs(2.7±0.8)mmol、L],and Hb[(110.6±22.5)g、L vs(105.5±31.7)g、L]were significant higher in TN group than those in Non-TN group(P <0.05). Conclusions The thyroid nodule is common in centenarian population and its prevalence was higher in female than male.The associations between TN and biomarkers of dyslipidemia and anemia are found in the present study.

Objective: To study the correlation of lifestyle characteristics with thyroid nodules in a population-based sample of centenarians in Hainan. Methods: The study was based on China Hainan Centenarian Cohort Study (CHCCS) conducted in 18 cities and counties in Hainan province from 2014 to 2016. A group of multidisciplinary team interviewed and examined local centenarians with structured questionnaires and ultrasonography procedures. A total of 918 centenarians were analyzed after excluding those who refused ultrasonographic examinations or had relevant missing data. Thyroids of centenarians were examined by 3-year experienced sonographer, details on lifestyle characteristics and dietary habits were collected by standard procedure. Results: Of the 918 centenarians, 683 (74.4%) had thyroid nodules under the ultrasonography procedures. The prevalence of thyroid nodules in different group of areca nut consumption varied significantly (P<0.05). In multivariate logistic regression model, the results showed female and areca nut intake were independently associated with thyroid nodules in centenarians (P<0.05). Conclusions The modifiable variables including areca nut intake as well as non-modifiable such as gender are independent determinants of thyroid nodules in centenarians. Further studies are warranted to explore and verify these associations in populations with different ranges of age.