ABSTRACT
Objective@#Recent advances in epigenetic studies continue to reveal novel mechanisms of gene regulation and control, however little is known on the role of epigenetics in sensorineural hearing loss (SNHL) in humans. We aimed to investigate the methylation patterns of two regions, one in RB1 and another in GJB2 in Filipino patients with SNHL compared to hearing control individuals. @*Methods@#We investigated an RB1 promoter region that was previously identified as differentially methylated in children with SNHL and lead exposure. Additionally, we investigated a sequence in an enhancer-like region within GJB2 that contains four CpGs in close proximity. Bisulfite conversion was performed on salivary DNA samples from 15 children with SNHL and 45 unrelated ethnically-matched individuals. We then performed methylation-specific real-time PCR analysis (qMSP) using TaqMan® probes to determine percentage methylation of the two regions. @*Results@#Using qMSP, both our cases and controls had zero methylation at the targeted GJB2 and RB1 regions. @*Conclusion@#Our study showed no changes in methylation at the selected CpG regions in RB1 and GJB2 in the two comparison groups with or without SNHL. This may be due to a lack of environmental exposures to these target regions. Other epigenetic marks may be present around these regions as well as those of other HL-associated genes.
Subject(s)
Hearing Loss , MethylationABSTRACT
Background: Certain indigenous populations have been noted by the World Health Organization (WHO) to havethe highest prevalence ratesforchronicsuppurativeotitis media (CSOM), including the Australian Aborigines (28-43%), Greenlanders (2-10%) and Alaskan Eskimos (2-10%). Objectives: To determine the prevalence of common ear problems, particularly CSOM, among the indigenous Ati or Aeta community in Bolabog, Boracay, and to determine their hearing sensitivity using screening audiometry. Methods: Study Design - Descriptive cross-sectional study. Setting - A small Ati community in Bolabog, Boracay. Population - A total of 63 adults and children underwent medical interview and otoscopy. Additionally 24 had their hearing screened by audiometry. Results: About a quarter of the population participated in the study, including 41 children (40 percent of all children) and 22 adults (18 percent of all adults). Forty-six percent of children and 23 percent of adults who were examined had previous history of ear discharge, while 22 percent of children and 45 percent of adults who were examined had history of hearing loss. Seventeen percent of children had history of hearing loss in the family. CSOM was found in 18 (43.90 percent) children and 8 (36.36 percent) adults. Impacted cerumen was found in 17.1 percent of children. Eleven female children underwent screening audiometry. Of these, eight had normal hearing and three had abnormal findings. Thirteen adults were also tested, five of whom were male and had normal hearing bilaterally. Four of eight female adults had abnormal hearing, of which three were unilateral. Conclusions: The Ati population in Bolabog, Boracay belongs to a group with the highest prevalence rates for CSOM (27.0 percent). A bigger sample for screening audiometry is required for proper estimation of hearing loss prevalence. Both environmental and genetic factors may have increased the prevalence of CSOM in the Ati population of Boracay. (Author)