Monogenic etiologies of persistent human papillomavirus infections: A comprehensive systematic review.

PURPOSE: Persistent human papillomavirus infection (PHPVI) causes cutaneous, anogenital, and mucosal warts. Cutaneous warts include common warts, Treeman syndrome, and epidermodysplasia verruciformis, among others. Although more reports of monogenic predisposition to PHPVI have been published with the development of genomic technologies, genetic testing is rarely incorporated into clinical assessments. To encourage broader molecular testing, we compiled a list of the various monogenic etiologies of PHPVI. METHODS: We conducted a systematic literature review to determine the genetic, immunological, and clinical characteristics of patients with PHPVI. RESULTS: The inclusion criteria were met by 261 of 40,687 articles. In 842 patients, 83 PHPVI-associated genes were identified, including 42, 6, and 35 genes with strong, moderate, and weak evidence for causality, respectively. Autosomal recessive inheritance predominated (69%). PHPVI onset age was 10.8 ± 8.6 years, with an interquartile range of 5 to 14 years. GATA2,IL2RG,DOCK8, CXCR4, TMC6, TMC8, and CIB1 are the most frequently reported PHPVI-associated genes with strong causality. Most genes (74 out of 83) belong to a catalog of 485 inborn errors of immunity-related genes, and 40 genes (54%) are represented in the nonsyndromic and syndromic combined immunodeficiency categories. CONCLUSION: PHPVI has at least 83 monogenic etiologies and a genetic diagnosis is essential for effective management.

Decellularized skin pretreatment by monophosphoryl lipid A and lactobacillus casei supernatant accelerate skin recellularization.

BACKGROUND: Bioscaffolds and cells are two main components in the regeneration of damaged tissues via cell therapy. Umbilical cord stem cells are among the most well-known cell types for this purpose. The main objective of the present study was to evaluate the effect of the pretreatment of the foreskin acellular matrix (FAM) by monophosphoryl lipid A (MPLA) and Lactobacillus casei supernatant (LCS) on the attraction of human umbilical cord mesenchymal stem cells (hucMSC). METHODS AND RESULTS: The expression of certain cell migration genes was studied using qRT-PCR. In addition to cell migration, transdifferentiation of these cells to the epidermal-like cells was evaluated via immunohistochemistry (IHC) and immunocytochemistry (ICC) of cytokeratin 19 (CK19). The hucMSC showed more tissue tropism in the presence of MPLA and LCS pretreated FAM compared to the untreated control group. We confirmed this result by scanning electron microscopy (SEM) analysis, glycosaminoglycan (GAG), collagen, and DNA content. Furthermore, IHC and ICC data demonstrated that both treatments increase the protein expression level of CK19. CONCLUSION: Pretreatment of acellular bioscaffolds by MPLA or LCS can increase the migration rate of cells and also transdifferentiation of hucMSC to epidermal-like cells without growth factors. This strategy suggests a new approach in regenerative medicine.

A novel heterozygous truncating variant in the AGO1 gene in an Iranian family with schizophrenia as an unreported symptom.

Intellectual disability (ID) and autism spectrum disorders (ASDs) are the most common developmental disorders in humans. Combined, they affect between 3% and 5% of the population. Although high-throughput genomic methods are rapidly increasing the pool of ASD genes, many cases remain idiopathic. AGO1 is one of the less-known genes related to ID/ASD. This gene encodes a core member protein of the RNA-induced silencing complex, which suppresses mRNA expression through cleavage, degradation, and/or translational repression. Generally, patients with defects in the AGO1 gene manifest varying degrees of ID, speech delay, and autistic behaviors. Herein, we used whole-exome sequencing (WES) to investigate an Iranian family with two affected members one of whom manifested ID and autism and the other showed borderline ID and schizophrenia. WES analysis identified a novel heterozygous truncating variant (NM_012199.5:c.1298G > A, p.Trp433Ter) in the AGO1 gene that co-segregated with the phenotypes using Sanger sequencing. Moreover, the structural analysis showed that due to this variant, two critical domains (Mid and PIWI) of the AGO1 protein have been lost, which has a detrimental effect on the protein's function and structure. To the best of our knowledge, schizophrenia has not been reported in patients with AGO1 deficiency, which is a novel phenotypic finding that expands the AGO1-related behavioral disorders. Moreover, this study's findings determined that patients with the same variant in the AGO1 gene may show heterogeneity in manifested phenotypes.

Griscelli syndrome type 1: a novel pathogenic variant, and review of literature.

Griscelli syndrome type 1 (GS1) is a rare inherited autosomal recessive disease caused by a deleterious variant in the MYO5A gene and characterized by general hypopigmentation, neurological symptoms, motor disability, hypotonia, and vision abnormality. Only nine pathogenic variants in the MYO5A gene have been confirmed in association with the GS1. All of the reported pathogenic variants are truncating. Herein, two siblings from a consanguineous Iranian family with abnormal pigmentation and neurological symptoms were referred for genetic counseling. Whole-exome sequencing (WES) revealed a novel homozygous truncating variant c.1633_1634delAA (p.Asn545Glnfs*10) in the MYO5A gene, which was completely co-segregated with the phenotype in all affected and unaffected family members. Computational analysis and protein modeling demonstrated the deleterious effects of this variant on the structure and function of the protein. The variant, according to ACMG guidelines, was classified as pathogenic. Besides the novelty of the identified variant, our patients manifested more severe clinical symptoms and presented distal hyperlaxity in all four limbs, which was a new finding. In conclusion, we expanded the mutational and phenotypic spectrum of the GS1. Moreover, by studying clinical manifestations in all molecularly confirmed reported cases, provided a comprehensive overview of clinical presentation, and attempted to find a genotype-phenotype correlation.

New molecular insights into the A218V variant impact on the steroidogenic acute regulatory protein (STAR) associated with 46, XY disorders of sexual development.

Disorders of sexual development (DSD) are an abnormal congenital conditions associated with atypical development of the urogenital tract and external genital structures. The steroidogenic acute regulatory (STAR) gene, associated with congenital lipoid adrenal hyperplasia (CLAH), is included in the targeted gene panel for the DSD diagnosis. Therefore, the genetic alterations of the STAR gene and their molecular effect were examined in the CLAH patients affected with DSD. Ten different Iranian families including twelve male pseudo-hermaphroditism patients with CLAH phenotype were studied using genetic linkage screening and STAR gene sequencing in the linked families to the STAR locus. Furthermore, the structural, dynamical, and functional impacts of the variants on the STAR in silico were analyzed. Sanger sequencing showed the pathogenic variant p.A218V in STAR gene, as the first report in Iranian population. Moreover, modeling and simulation analysis were performed using tools such as radius of gyration, root mean square deviation (RMSD), root mean square fluctuation (RMSF), and molecular docking showed that p.A218V variant affects the residues interaction in cholesterol-binding site and the proper folding of STAR through increasing H-bound and the amount of α-Helix, deceasing total flexibility and changing fluctuations in some residues, resulting in reduced steroidogenic activity of the STAR protein. The study characterized the structural and functional changes of STAR caused by pathogenic variant p.A218V. It leads to limited cholesterol-binding activity of STAR, ultimately leading to the CLAH disease. Molecular dynamics simulation of STAR variants could help explain different clinical manifestations of CLAH disease.

Next-generation sequencing reveals a novel pathogenic variant in the ATM gene.

INTRODUCTION: Ataxia telangiectasia (A-T) is a rare autosomal recessive, multisystemic disease. Patients with the A-T syndrome present a broad spectrum of disease phenotypes. The ATM (ataxia telangiectasia mutated) gene, the only causative gene for A-T. METHOD: A patient of Persian origin presenting with typical A-T was referred to our genetics centre for specialized genetic counselling and testing. Targeted next-generation sequencing (NGS) was applied. Sanger sequencing was used to confirm the candidate variant. Modelling was performed using the SWISS-MODEL server. RESULTS: A homozygous stop-gain variant c.829G > T (p.E277*) was found in the ATM gene. This variant was confirmed by Sanger sequencing and modelling of native structure, and truncated structure was performed. CONCLUSION: To date, very few pathogenic variants of the ATM gene have been reported from the Iranian population. The finding has implications in molecular diagnostic for A-T in Iran.

Homozygous TFG gene variants expanding the mutational and clinical spectrum of hereditary spastic paraplegia 57 and a review of literature.

In recent years, the tropomyosin-receptor kinase fused gene (TFG) has been linked to diverse hereditary neurodegenerative disorders, including a very rare complex hereditary spastic paraplegia, named spastic paraplegia type 57 (SPG57). Until now, four pathogenic homozygous variants of the TFG gene have been reported associated with SPG57. Two consanguineous Iranian families (1 and 2), the first one with two affected members and the second one with one, all with an early-onset progressive muscle weakness, spasticity, and several neurological symptoms were examined via the whole-exome sequencing. Two homozygous missense variants including c.41A>G (p.Lys14Arg) and c.316C>T (p.Arg106Cys) have been found in the related families. The candidate variants were confirmed by Sanger sequencing and found to co-segregate with the disease in families. The bioinformatics analysis showed the deleterious effects of these nucleotide changes and the variants were classified as pathogenic according to ACMG guidelines. A comparison of the clinical presentation of the patients harboring c.41A>G (p.Lys14Arg) with previously reported SPG57 revealed variability in the severity state and unreported clinical presentation, including, facial atrophy, nystagmus, hyperelastic skin, cryptorchidism, hirsutism, kyphoscoliosis, and pectus excavatum. The affected member of the second family carried a previously reported homozygous c.316C>T (p.Arg106Cys) variant and displayed a complex HSP including optic atrophy. Remarkable clinical differences were observed between the family 1 and 2 harboring the c.41A>G (p.Lys14Arg) and c.316C>T (p.Arg106Cys) variants, which could be attributed to the distinct affected domains (PB1 domains and coiled-coil domains), and therefore, SPG57 might have been representing phenotype vs. variant position correlation.

A novel pathogenic variant in the LRTOMT gene causes autosomal recessive non-syndromic hearing loss in an Iranian family.

BACKGROUND: Hearing loss (HL) is the most common sensorineural disorder with high phenotypic and genotypic heterogeneity, which negatively affects life quality. Autosomal recessive non-syndromic hearing loss (ARNSHL) constitutes a major share of HL cases. In the present study, Whole exome sequencing (WES) was applied to investigate the underlying etiology of HL in an Iranian patient with ARNSHL. METHODS: A proband from an Iranian consanguineous family was examined via WES, following GJB2 sequencing. WES was utilized to find possible genetic etiology of the disease. Various Bioinformatics tools were used to assess the pathogenicity of the variants. Co-segregation analysis of the candidate variant was carried out. Interpretation of variants was performed according to the American College of Medical Genetics and Genomics (ACMG) guidelines. RESULTS: WES results showed a novel frameshift (16 bp deletion) variant (p.Ala170Alafs*20) in the LRTOMT gene. This variant, which resides in exon 6, was found to be co-segregating in the family. It fulfils the criteria set by the ACMG guidelines of being pathogenic. CONCLUSION: Here, we report successful application of WES to identify the molecular pathogenesis of ARNSHL, which is a genetically heterogeneous disorder, in a patient with ARNSHL.

Clinical and genetic analysis of two wolfram syndrome families with high occurrence of wolfram syndrome and diabetes type II: a case report.

BACKGROUND: Mutations of the WFS1 gene are responsible for most cases of Wolfram syndrome (WS), a rare, recessively inherited neurodegenerative disorder characterized by juvenile-onset non-autoimmune diabetes mellitus and optic atrophy. Variants of WFS1 are also associated with non-syndromic hearing loss and type-2 diabetes mellitus (T2DM). Our study adds to literature significant associations between WS and T2DM. CASE PRESENTATION: In this study, we analyzed the clinical and genetic data of two families with high prevalence of WS and T2DM. Genetic linkage analysis and DNA sequencing were exploited to identify pathogenic variants. One novel pathogenic variant (c.2243-2244insC) and one known pathogenic (c.1232_1233delCT) (frameshift) variant were identified in exon eight of WFS1 gene. CONCLUSIONS: The mutational and phenotypic spectrum of WS is broadened by our report of novel WFS1 mutation. Our results reveal the value of molecular analysis of WFS1 in the improvement of clinical diagnostics for WS. This study also confirms the role of WFS1 in T2DM.

Correction to: Clinical and genetic analysis of two wolfram syndrome families with high occurrence of wolfram syndrome and diabetes type II: a case report.

Following publication of the original article [1], the authors flagged that the name of 'Asal Hojjat' was misspelled; the name had been spelled as 'Asal Hojat'.

Whole exome sequencing identifies novel compound heterozygous pathogenic variants in the MYO15A gene leading to autosomal recessive non-syndromic hearing loss.

Autosomal recessive non-syndromic hearing loss (ARNSHL) is a highly heterogeneous disease, for which more than 70 genes have been identified. MYO15A mutations have been reported to cause congenital severe-to-profound HL. In this study, we applied the whole exome sequencing (WES) to find the cause of HL in an Iranian family. A proband from an Iranian non-consanguineous family with hearing impaired parents, was examined via WES, after excluding GJB2 mutations as the most common ARNSHL gene via Sanger sequencing. Co-segregation analysis of the candidate variant was done in the family members. Interpretation of variants was according to the American College of Medical Genetics and Genomics (ACMG) guidelines. WES results showed novel compound heterozygous variants (p.Arg1507Ter and p.Val2815Valfs*10) in the MYO15A gene. These two variants, residing in highly conserved regions, were found to be co-segregating in the family and fulfill the criteria of being categorized as pathogenic, according to the ACMG guidelines. Here, we report successful application of WES to identify the molecular pathogenesis of ARNSHL in a patient with ARNSHL, as an example of an extremely heterogeneous disease. In agreement with previous studies, MYO15A is regarded to be important in causing HL in Iran.

A Novel Cadherin 23 Variant for Hereditary Hearing Loss Reveals Additional Support for a DFNB12 Nonsyndromic Phenotype of CDH23.

BACKGROUND AND OBJECTIVES: Identification of the pathogenic mutations underlying hereditary hearing loss (HL) is difficult, since causative mutations in 60 different genes have so far been reported. METHODS: A comprehensive clinical and pedigree examination was performed on a multiplex family suffering from HL. Direct sequencing of GJB2 and genetic linkage analysis of 5 other most common recessive nonsyndromic HL (ARNSHL) genes were accomplished. Next-generation sequencing (NGS) was utilized to reveal the possible genetic etiology of the disease. RESULTS: NGS results showed a novel rare variant c.2977G>A (p.Asp993Asn) in the CDH23 gene. The variant, which is a missense in exon 26 of the CDH23 gene, fulfills the criteria of being categorized as pathogenic according to the American College of Medical Genetics and Genomics (ACMG) guideline. Electroretinography rejects the Usher syndrome in the family. CONCLUSIONS: The present study shows that an accurate molecular diagnosis based on NGS technologies largely improves molecular-diagnostic outcome and thus genetic counseling, and helps to clarify the recurrence risk in deaf families.

Upregulation of MTOR, RPS6KB1, and EIF4EBP1 in the whole blood samples of Iranian patients with multiple sclerosis compared to healthy controls.

Various genetic and epigenetic mechanisms have been suggested to play roles as the underlying pathophysiology of Multiple Sclerosis (MS). Changes in different parts of the mTOR signaling pathway are among the potential suggested mechanisms based on the specific roles of this pathway in CNS. MTOR, RPS6KB1, and EIFEBP1 genes are among important genes in the mTOR pathway, responsible for the proper function of acting proteins in this signaling pathway. This study aimed to investigate the relative expression levels of these genes in the blood samples of relapsing-remitting MS (RRMS) patients compared to healthy controls. In this case-control study blood samples were collected from 30 newly diagnosed RRMS patients and 30 age and sex-matched healthy controls. mRNA level of MTOR, RPS6KB1, and EIFEBP1 genes were assessed using Real-Time PCR. The expression of MTOR, RPS6KB1, and EIF4EBP1 genes was up regulated in MS patients compared to healthy controls (p < 0.001 for all mentioned genes). Considering gender differences, expression of the mentioned genes was increased among female patients (all P < 0.001). However, no statistically significant changes were observed among male patients. Based on the receiver operating characteristic, MTOR gene had the highest diagnostic value followed by EIF4EBP1 and RPS6KB1 genes in differentiating RRMS patients from controls. In conclusion, we found the simultaneous upregulation of MTOR, RPS6KB1, and EIF4EBP1 genes among RRMS patients. MTOR showed to have the highest diagnostic value compared to other 2 genes in differentiating RRMS patients. Further studies evaluating the importance of these findings from pharmacological and prognostic perspectives are necessary.

A novel pathogenic variant in the MARVELD2 gene causes autosomal recessive non-syndromic hearing loss in an Iranian family.

BACKGROUND AND AIMS: Hearing loss (HL) is the most common sensorineural disorder and one of the most common human defects. HL can be classified according to main criteria, including: the site (conductive, sensorineural and mixed), onset (pre-lingual and post-lingual), accompanying signs and symptoms (syndromic and non-syndromic), severity (mild, moderate, severe and profound) and mode of inheritance (Autosomal recessive, autosomal dominant, X-linked and mitochondrial). Autosomal recessive non-syndromic HL (ARNSHL) forms constitute a major share of the HL cases. In the present study, next-generation sequencing (NGS) was applied to investigate the underlying etiology of HL in a multiplex ARNSHL family from Khuzestan province, southwest Iran. METHODS: In this descriptive study, 20 multiplex ARNSHL families from Khuzestan province, southwest of Iran were recruited. After DNA extraction, genetic linkage analysis (GLA) was applied to screen for a panel of more prevalent loci. One family, which was not linked to these loci, was subjected to Otogenetics deafness Next Generation Sequencing (NGS) panel. RESULTS: NGS results showed a novel deletion-insertion variant (c.1555delinsAA) in the MARVELD2 gene. The variant which is a frameshift in the seventh exon of the MARVELD2 gene fulfills the criteria of being categorized as pathogenic according to the American College of Medical Genetics and Genomics (ACMG) guideline. CONCLUSION: NGS is very promising to identify the molecular etiology of highly heterogeneous diseases such as HL. MARVELD2 might be important in the etiology of HL in this region of Iran.

Engineered zinc-finger nuclease to generate site-directed modification in the KLF1 gene for fetal hemoglobin induction.

Elevation of hemoglobin F (HbF) ameliorates symptoms of ß-thalassemia, as a common autosomal recessive disorder. In this study, the ability of an engineered zinc-finger nuclease (ZFN) system was assesed to disrupt the KLF1 gene to inhibit the γ to ß hemoglobin switching in K562 cells. This study was performed using a second generation integration-deficient lentiviral vector assigned to transient gene targeting. The sequences coding for zinc finger protein arrays were designed and subcloned in TDH plus as a transfer vector. Transduction of K562 cells was performed with the integrase minus lentivirus containing ZFN. The indel percentage of the transducted cells with lentivirus containing ZFN was about 29%. Differentiation of K562 cell line into erythroid cell lineage was induced with cisplatin concentration of 15 µg/mL. After differentiation, γ-globin and HbF expression were evaluated using real-time reverse-transcription polymerase chain reaction and hemoglobin electrophoresis methods. The levels of γ-globin messenger RNA were nine-fold higher in the ZFN treated cells compared with untreated cells 5 days after differentiation. Hemoglobin electrophoresis method showed the same results for HbF level measurement. Application of the ZFN tool to induce KLF1 gene mutation in adult erythroid progenitors might be a candidate to stimulate HbF expression in ß-thalassemia patients.

Molecular genetic study of glutaric aciduria, type I: Identification of a novel mutation.

Glutaric acidemia type I (GA-1) is an inborn error of metabolism due to deficiency of glutaryl-CoA dehydrogenase (GCDH), which catalyzes the conversion of glutaryl-CoA to crotonyl-CoA. GA-1 occurs in about 1 in 100 000 infants worldwide. The GCDH gene is on human chromosome 19p13.2, spans about 7 kb and comprises 11 exons and 10 introns. Tandem mass spectrometry (MS/MS) was used for clinical diagnosis in a proband from Iran with GA-1. Sanger sequencing was performed using primers specific for coding exons and exon-intron flanking regions of the GCDH gene in the proband. Cosegregation analysis and in silico assessment were performed to confirm the pathogenicity of the candidate variant. A novel homozygous missense variant c.1147C > A (p.Arg383Ser) in exon 11 of GCDH was identified. Examination of variant through in silico software tools determines its deleterious effect on protein in terms of function and stability. The variant cosegregates with the disease in family. In this study, the clinical and molecular aspects of GA-1 were investigated, which showed one novel mutation in the GCDH gene in an Iranian patient. The variant is categorized as pathogenic according to the the guideline of the American College of Medical Genetics and Genomics (ACMG) for variant interpretation. This mutation c.1147C > A (p.Arg383Ser) may also be prevalent among Iranian populations.

A Novel Pathogenic Variant in the CABP2 Gene Causes Severe Nonsyndromic Hearing Loss in a Consanguineous Iranian Family.

BACKGROUND AND OBJECTIVES: Hereditary hearing loss (HL) can originate from mutations in one of many genes involved in the complex process of hearing. CABP2 mutations have been reported to cause moderate HL. Here, we report the whole exome sequencing (WES) of a proband presenting with prelingual, severe HL in an Iranian family. METHODS: A comprehensive family history was obtained, and clinical evaluations and pedigree analysis were performed in the family with 2 affected members. After excluding mutations in the GJB2 gene and 7 other most common autosomal recessive nonsyndromic HL (ARNSHL) genes via Sanger sequencing and genetic linkage analysis in the family, WES was utilized to find the possible etiology of the disease. RESULTS: WES results showed a novel rare variant (c.311G>A) in the CABP2gene.This missense variant in the exon 4 of the CABP2gene meets the criteria of being pathogenic according to the American College of Medical Genetics and Genomics (ACMG) interpretation guidelines. CONCLUSIONS: Up to now, 3 mutations have been reported for the CABP2gene to cause moderate ARNSHL in different populations. Our results show that CABP2variantsalso cause severe ARNSHL, adding CABP2to the growing list of genes that exhibit phenotypic heterogeneity. Expanding our understanding of the mutational spectrum of HL genes is an important step in providing the correct clinical molecular interpretation and diagnosis for patients.

Identification and Clinical Implications of a Novel MYO15A Variant in a Consanguineous Iranian Family by Targeted Exome Sequencing.

BACKGROUND AND OBJECTIVES: Hereditary hearing loss (HL) is known by a very high genetic heterogeneity, which makes a molecular diagnosis problematic. Next-generation sequencing (NGS) is a new strategy that can overcome this problem. METHOD: A comprehensive family history was obtained, and clinical evaluations and pedigree analysis were performed in the family with 3 affected members. After excluding mutations in the GJB2 and 7 other most common autosomal recessive nonsyndromic HL genes via Sanger sequencing and genetic linkage analysis in the family, we applied the Otogenetics deafness NGS panel in the proband of this family. RESULTS: NGS results showed a novel rare variant (c.7720C>T) in the MYO15A gene. This nonsense variant in the exon 40 of the MYO15A gene fulfills the criteria of being categorized as pathogenic according to the American College of Medical Genetics and Genomics guideline. CONCLUSIONS: New DNA sequencing technologies could lead to identification of the disease causing variants in highly heterogeneous disorders such as HL.

Epigenetics and Common Non Communicable Disease.

Common Non communicable diseases (NCDs), such as cardiovascular disease, cancer, schizophrenia, and diabetes, have become the major cause of death in the world. They result from an interaction between genetics, lifestyle and environmental factors. The prevalence of NCDs are increasing, and researchers hopes to find efficient strategies to predict, prevent and treat them. Given the role of epigenome in the etiology of NCDs, insight into epigenetic mechanisms may offer opportunities to predict, detect, and prevent disease long before its clinical onset.Epigenetic alterations are exerted through several mechanisms including: chromatin modification, DNA methylation and controlling gene expression by non-coding RNAs (ncRNAs). In this chapter, we will discuss about NCDs, with focus on cancer, diabetes and schizophrenia. Different epigenetic mechanisms, categorized into two main groups DNA methylation and chromatin modifications and non-coding RNAs, will be separately discussed for these NCDs.

A pathogenic variant in SLC26A4 is associated with Pendred syndrome in a consanguineous Iranian family.

Objective: Hearing loss (HL) is a common sensory deficit with high phenotypic and genotypic heterogeneity. A large Iranian family with HL was genetically assessed in this study. Design: A proband from a consanguineous multiplex HL family from Iran was examined via Targeted Next-Generation Sequencing (TNGS). Sanger sequencing allowed the segregation analysis of the variant of interest and the investigation of its presence in a cohort of 50 ethnicity-matched healthy control individuals. The gene was previously associated with HL. Therefore, to determine whether the variant was specifically associated with Pendred Syndrome (PDS) or DFNB4, biochemical analyses, PTA, thyroid scans by Tc99m, perchlorate discharge test and high-resolution CT scan of the temporal bone were carried out on the affected family members. Study sample: Ten members of a large multiplex Iranian family with HL were recruited in this study. In addition, 50 unrelated healthy controls of the same ethnic group were randomly selected to genotype the variant. Results: A homozygous missense variant (NM_000441.1: c.1211C > T/p.Thr404Ile) in exon 10 was found segregating in the family. Based on the ACMG's guidelines, the variant was classified as pathogenic. Conclusion: This study expands the spectrum of SLC26A4 pathogenic variants in hearing loss.