Mitochondrial gene mutation screening in hearing loss patients, Hormozgan, Iran

Introduction: Hearing loss is the most frequent sensory disorder occurs in 1/1000 newborns. About 50% of hearing loss cases are due to genetic causes. Mutation in MTRNR1(A1555G), MTTL1(A3243G) and MTTS1(A7445G) are known to be one of the important cause of nonsyndromic Sensorineural hearing loos in some populations. This study aims to demonstrate the frequency of three mitochondrial mutations including A1555G, A7445G and A3243G in deaf subjects in Hormozgan province. Methods: We investigated the presence of three mitochondrial mutations including A1555G، A3243G and A7445G in a cohort of 110 nonsyndromic Sensorineural hearing loss subjects. DNA was extracted using standard phenol – chloroform method. The screening of gene mutations was performed by PCR-RFLP procedure. Finally, the possible mutations were confirmed by direct sequencing. Results: None of the 110 subjects were found to carry A1555G, A3243G and A7445G mutations. However, PCR-RFLP of the MTTL1 gene destroyed a restriction site due to G3316A substitution in a deaf subject. Conclusion: We found that the association of A1555G، A3243G and A7445G mutations with hearing loss in Hormozgan is negligible.