AUTHOR=Bouzid Amal , Smeti Ibtihel , Chakroun Amine , Loukil Salma , Gibriel Abdullah Ahmed , Grati Mhamed , Ghorbel Abdelmonem , Masmoudi Saber 

TITLE=CDH23 Methylation Status and Presbycusis Risk in Elderly Women

JOURNAL=Frontiers in Aging Neuroscience

VOLUME=10

YEAR=2018

URL=https://www.frontiersin.org/journals/aging-neuroscience/articles/10.3389/fnagi.2018.00241

DOI=10.3389/fnagi.2018.00241

ISSN=1663-4365

ABSTRACT=<p><bold>Introduction</bold>: Presbycusis, an age-related hearing impairment (ARHI) disease, is the most common cause for HI in adults worldwide. One of the best candidate genes for ARHI susceptibility is Cadherin 23 (<italic>CDH23</italic>) which encodes stereocilia tip-links of the inner ear sensory hair cell. Although alterations in the methylation status of CpG dinucleotides across various genes were reported to be associated with HI, methylation changes in <italic>CDH23</italic> gene have not been reported previously.</p><p><bold>Objectives</bold>: This study aimed at investigating whether DNA methylation level of <italic>CDH23</italic> gene at intragenic CpG island overlapping an exonic-intronic region at position chr10:73565570-73565827 (GRCh37/hg19) could be risk factor associated with ARHI.</p><p><bold>Materials and Methods</bold>: We screened for methylation changes in this particular position for <italic>CDH23</italic> gene in 50 blood samples of elderly women affected with presbycusis and healthy control cohort. Methylation of CpG sites were assessed using Quantitative methylation-specific PCR (qMSP) following sodium bisulfite DNA conversion chemistry. Methylation levels were normalized against <italic>TSH2B</italic> reference gene.</p><p><bold>Results</bold>: DNA methylation analysis for the common CpG islands in <italic>CDH23</italic> gene revealed 3.27-folds significant increase (<italic>p</italic> &lt; 0.0001) in methylation profile for ARHI women as compared to healthy controls with an elevated risk odds ratio (OR) of 2.219 [95% CI 1.071–4.597].</p><p><bold>Conclusion</bold>: Our study is the first of its kind to prove that higher CpG site methylation levels in <italic>CDH23</italic> gene are likely to be associated with ARHI.</p>