Marzieh Arshadi - Department of Biology, School of Basic Science, Science and Research Branch, Islamic Azad University, Tehran. Iran
Saeid Morovvati - Human Genetics Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
Fatemeh Ghadiani - Human Genetics Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
Fatemeh Minoochehr - Human Genetics Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.

Introduction: Hearing loss is the most common birth defect and the most prevalent sensorineural disorder in developed countries. One of every 500 newborns has bilateralpermanent sensorineural hearing loss ≥40 dB; by adolescence, prevalence increases to 3.5 per 1000. Deafness can also result from environmental factors or a combination of genetic and environmental factors. Materials and Methods: We describe an 8-year-old symptomatic female affected by hereditary hearing loss. Her parents are first cousins once removed. Her cousins are affected by deafness as well. Peripheral blood obtained from patient and her parents and cousins, and DNA was extracted using a standard method. Genetic analysis of the patient was performed on 127 genes involved in hereditary hearing loss using NGS method. Direct sequencing of SLC26A4 gene in her parents and cousins where the affected child showed the mutation was performed using Sanger sequencing method. Results: We found a novel homozygous mutation, c.2048T> C (p.Phe683Ser), in SLC26A4 gene in the affected girl. The same mutation was found in heterozygous states in her parents and in homozygous states in her affected cousins.Discussion: The detected variant has not previously been reported for its pathogenicity and has unknown clinical significance. However, it is predicted to be damaging by SIFT, Polyphen-2, Condel, Provean and Mutation Taster. Frequency of the variant is zero in large population databases including 1000 Genomes, 5000 Exomes, dbSNP and Exome Aggregation Consortium. Pathogenic variant in the SLC26A4 gene have been found to cause Pendred Syndrome and a form of autosomal recessive nonsyndromic hearing loss, celled DFNA4.

SLC26A4, gene, Novel, deafness