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Almalki F. Review and research gap identification in genetics causes of syndromic and nonsyndromic hearing loss in Saudi Arabia. Ann Hum Genet 2024. [PMID: 38517009 DOI: 10.1111/ahg.12559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 02/13/2024] [Accepted: 03/04/2024] [Indexed: 03/23/2024]
Abstract
Congenital hearing loss is one of the most common sensory disabilities worldwide. The genetic causes of hearing loss account for 50% of hearing loss. Genetic causes of hearing loss can be classified as nonsyndromic hearing loss (NSHL) or syndromic hearing loss (SHL). NSHL is defined as a partial or complete hearing loss without additional phenotypes; however, SHL, known as hearing loss, is associated with other phenotypes. Both types follow a simple Mendelian inheritance fashion. Several studies have been conducted to uncover the genetic factors contributing to NSHL and SHL in Saudi patients. However, these studies have encountered certain limitations. This review assesses and discusses the genetic factors underpinning NSHL and SHL globally, with a specific emphasis on the Saudi Arabian context. It also explores the prevalence of the most observed genetic causes of NSHL and SHL in Saudi Arabia. It also sheds light on areas where further research is needed to fully understand the genetic foundations of hearing loss in the Saudi population. This review identifies several gaps in research in NSHL and SHL and provides insights into potential research to be conducted.
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Affiliation(s)
- Faisal Almalki
- Medical Laboratories Technology Department, College of Applied Medical Sciences, Taibah University, Al Madinah Al Munwarah, Saudi Arabia
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Cellular and Molecular Mechanisms of Pathogenesis Underlying Inherited Retinal Dystrophies. Biomolecules 2023; 13:biom13020271. [PMID: 36830640 PMCID: PMC9953031 DOI: 10.3390/biom13020271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/23/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
Inherited retinal dystrophies (IRDs) are congenital retinal degenerative diseases that have various inheritance patterns, including dominant, recessive, X-linked, and mitochondrial. These diseases are most often the result of defects in rod and/or cone photoreceptor and retinal pigment epithelium function, development, or both. The genes associated with these diseases, when mutated, produce altered protein products that have downstream effects in pathways critical to vision, including phototransduction, the visual cycle, photoreceptor development, cellular respiration, and retinal homeostasis. The aim of this manuscript is to provide a comprehensive review of the underlying molecular mechanisms of pathogenesis of IRDs by delving into many of the genes associated with IRD development, their protein products, and the pathways interrupted by genetic mutation.
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Nie K, Huang J, Liu L, Lv H, Chen D, Fan W. Identification of a De Novo Heterozygous Missense ACTB Variant in Baraitser–Winter Cerebrofrontofacial Syndrome. Front Genet 2022; 13:828120. [PMID: 35401677 PMCID: PMC8989421 DOI: 10.3389/fgene.2022.828120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 02/23/2022] [Indexed: 11/21/2022] Open
Abstract
Baraitser–Winter cerebrofrontofacial syndrome (BWCFF, OMIM: 243310) is a rare autosomal-dominant developmental disorder associated with variants in the genes ACTB or ACTG1. It is characterized by brain malformations, a distinctive facial appearance, ocular coloboma, and intellectual disability. However, the phenotypes of BWCFF are heterogenous, and its molecular pathogenesis has not been fully elucidated. In the present study, we conducted detailed clinical examinations on a Chinese patient with BWCFF and found novel ocular manifestations including pseudoduplication of the optic disc and nystagmus. Targeted gene panel sequencing and Sanger sequencing identified a de novo heterozygous missense c.478A > G (p.Thr160Ala) variant in ACTB. The mRNA and protein expression of ACTB was assessed by quantitative reverse transcription PCR and Western blots. Furthermore, the functional effects of the pathogenic variant were analyzed by protein structure analysis, which indicated that the variant may affect the active site for ATP hydrolysis by the actin ATPase, resulting in abnormal filamentous actin organization in peripheral blood mononuclear cells. This discovery extends the ACTB variant spectrum, which will improve genetic counseling and diagnosis, and may contribute to understanding the pathogenic mechanisms of actin-related diseases.
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Affiliation(s)
- Kailai Nie
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
- Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Junting Huang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Longqian Liu
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Hongbin Lv
- Department of Ophthalmology, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Danian Chen
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
- Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
- *Correspondence: Wei Fan, ; Danian Chen,
| | - Wei Fan
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
- *Correspondence: Wei Fan, ; Danian Chen,
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Yusuf IH, Garrett A, MacLaren RE, Issa PC. Retinal cadherins and the retinal cadherinopathies: Current concepts and future directions. Prog Retin Eye Res 2022; 90:101038. [DOI: 10.1016/j.preteyeres.2021.101038] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 12/13/2021] [Accepted: 12/20/2021] [Indexed: 12/18/2022]
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Abstract
Usher syndrome (USH) encompasses a group of clinically and genetically heterogenous disorders defined by the triad of sensorineural hearing loss (SNHL), vestibular dysfunction, and vision loss. USH is the most common cause of deaf blindness. USH is divided clinically into three subtypes-USH1, USH2, and USH3-based on symptom severity, progression, and age of onset. The underlying genetics of these USH forms are, however, significantly more complex, with over a dozen genes linked to the three primary clinical subtypes and other atypical USH phenotypes. Several of these genes are associated with other deaf-blindness syndromes that share significant clinical overlap with USH, pointing to the limits of a clinically based classification system. The genotype-phenotype relationships among USH forms also may vary significantly based on the location and type of mutation in the gene of interest. Understanding these genotype-phenotype relationships and associated natural disease histories is necessary for the successful development and application of gene-based therapies and precision medicine approaches to USH. Currently, the state of knowledge varies widely depending on the gene of interest. Recent studies utilizing next-generation sequencing technology have expanded the list of known pathogenic mutations in USH genes, identified new genes associated with USH-like phenotypes, and proposed algorithms to predict the phenotypic effects of specific categories of allelic variants. Further work is required to validate USH gene causality, and better define USH genotype-phenotype relationships and disease natural histories-particularly for rare mutations-to lay the groundwork for the future of USH treatment.
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Novel compound heterozygous EYS variants may be associated with arRP in a large Chinese pedigree. Biosci Rep 2021; 40:224912. [PMID: 32436957 PMCID: PMC7268256 DOI: 10.1042/bsr20193443] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 04/22/2020] [Accepted: 04/29/2020] [Indexed: 12/11/2022] Open
Abstract
As a genetically heterogeneous ocular dystrophy, gene mutations with autosomal recessive retinitis pigmentosa (arRP) in patients have not been well described. We aimed to detect the disease-causing genes and variants in a Chinese arRP family. In the present study, a large Chinese pedigree consisting of 31 members including a proband and another two patients was recruited; clinical examinations were conducted; next-generation sequencing using a gene panel was used for identifying pathogenic genes, and Sanger sequencing was performed for verification of mutations. Novel compound heterozygous variants c.G2504A (p.C835Y) and c.G6557A (p.G2186E) for the EYS gene were identified, which co-segregated with the clinical RP phenotypes. Sequencing of 100 ethnically matched normal controls didn't found these mutations in EYS. Therefore, our study identified pathogenic variants in EYS that may cause arRP in this Chinese family. This is the first study to reveal the novel mutation in the EYS gene (c.G2504A, p.C835Y), extending its mutation spectrum. Thus, the EYS c.G2504A (p.C835Y) and c.G6557A (p.G2186E) variants may be the disease-causing missense mutations for RP in this large arRP family. These findings should be helpful for molecular diagnosis, genetic counseling and clinical management of arRP disease.
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de Bruijn SE, Fadaie Z, Cremers FPM, Kremer H, Roosing S. The Impact of Modern Technologies on Molecular Diagnostic Success Rates, with a Focus on Inherited Retinal Dystrophy and Hearing Loss. Int J Mol Sci 2021; 22:2943. [PMID: 33799353 PMCID: PMC7998853 DOI: 10.3390/ijms22062943] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/04/2021] [Accepted: 03/09/2021] [Indexed: 02/07/2023] Open
Abstract
The identification of pathogenic variants in monogenic diseases has been of interest to researchers and clinicians for several decades. However, for inherited diseases with extremely high genetic heterogeneity, such as hearing loss and retinal dystrophies, establishing a molecular diagnosis requires an enormous effort. In this review, we use these two genetic conditions as examples to describe the initial molecular genetic identification approaches, as performed since the early 90s, and subsequent improvements and refinements introduced over the years. Next, the history of DNA sequencing from conventional Sanger sequencing to high-throughput massive parallel sequencing, a.k.a. next-generation sequencing, is outlined, including their advantages and limitations and their impact on identifying the remaining genetic defects. Moreover, the development of recent technologies, also coined "third-generation" sequencing, is reviewed, which holds the promise to overcome these limitations. Furthermore, we outline the importance and complexity of variant interpretation in clinical diagnostic settings concerning the massive number of different variants identified by these methods. Finally, we briefly mention the development of novel approaches such as optical mapping and multiomics, which can help to further identify genetic defects in the near future.
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Affiliation(s)
- Suzanne E. de Bruijn
- Department of Human Genetics, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands; (S.E.d.B.); (Z.F.); (F.P.M.C.)
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands;
| | - Zeinab Fadaie
- Department of Human Genetics, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands; (S.E.d.B.); (Z.F.); (F.P.M.C.)
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands;
| | - Frans P. M. Cremers
- Department of Human Genetics, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands; (S.E.d.B.); (Z.F.); (F.P.M.C.)
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands;
| | - Hannie Kremer
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands;
- Department of Otorhinolaryngology, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands
| | - Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands; (S.E.d.B.); (Z.F.); (F.P.M.C.)
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands;
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Zardadi S, Razmara E, Asgaritarghi G, Jafarinia E, Bitarafan F, Rayat S, Almadani N, Morovvati S, Garshasbi M. Novel homozygous variants in the TMC1 and CDH23 genes cause autosomal recessive nonsyndromic hearing loss. Mol Genet Genomic Med 2020; 8:e1550. [PMID: 33205915 PMCID: PMC7767568 DOI: 10.1002/mgg3.1550] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/22/2020] [Accepted: 10/29/2020] [Indexed: 12/14/2022] Open
Abstract
Background Hereditary hearing loss (HL) is a heterogeneous and most common sensory neural disorder. At least, 76 genes have been reported in association with autosomal recessive nonsyndromic HL (ARNSHL). Herein, we subjected two patients with bilateral sensorineural HL in two distinct consanguineous Iranian families to figure out the underlying genetic factors. Methods Physical and sensorineural examinations were performed on the patients. Imaging also was applied to unveil any abnormalities in anatomical structures of the middle and inner ear. In order to decipher the possible genetic causes of the verified GJB2‐negative samples, the probands were subjected to whole‐exome sequencing and, subsequently, Sanger sequencing was applied for variant confirmation. Results Clinical examinations showed ARNSHL in the patients. After doing whole exome sequencing, two novel variants were identified that were co‐segregating with HL that were absent in 100 ethnically matched controls. In the first family, a novel homozygous variant, NM_138691.2: c.530T>C; p.(lle177Thr), in TMC1 gene co‐segregated with prelingual ARNSHL. In the second family, NM_022124.6: c.2334G>A; p.(Trp778*) was reported as a nonsense variant causing prelingual ARNSHL. Conclusion These findings can, in turn, endorse how TMC1 and CDH23 screening is critical to detecting HL in Iranian patients. Identifying TMC1 and CDH23 pathogenic variants doubtlessly help in the detailed genotypic characterization of HL.
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Affiliation(s)
- Safoura Zardadi
- Department of Biology, School of Basic Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Ehsan Razmara
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Golareh Asgaritarghi
- Department of Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Ehsan Jafarinia
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Fatemeh Bitarafan
- Department of Cellular and Molecular Biology, North Tehran Branch, Islamic Azad University, Tehran, Iran
| | - Sima Rayat
- Department of Biology, School of Basic Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Navid Almadani
- Department of Genetics, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran
| | - Saeid Morovvati
- Department of Genetics, Faculty of Advanced Sciences and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Masoud Garshasbi
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
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Fu J, Cheng J, Zhou Q, Khan MA, Duan C, Peng J, Lv H, Fu J. Novel compound heterozygous nonsense variants, p.L150* and p.Y3565*, of the USH2A gene in a Chinese pedigree are associated with Usher syndrome type IIA. Mol Med Rep 2020; 22:3464-3472. [PMID: 32945453 PMCID: PMC7453661 DOI: 10.3892/mmr.2020.11400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 07/06/2020] [Indexed: 12/14/2022] Open
Abstract
Usher syndrome refers to a group of genetically and clinically heterogeneous autosomal recessive diseases with retinitis pigmentosa (RP) and hearing deficiencies. The association between Usher syndrome-causative genes and resultant Usher syndrome phenotypes in patients are highly variable. In the present study, a Chinese family with Usher syndrome was recruited, and targeted next-generation sequencing, Sanger sequencing and segregation analysis were performed. The expression profiles and functional effects of the pathogenic variants of USH2A identified were analyzed. Novel nonsense compound heterozygous variants, c.T449G (p.L150*) and c.T10695A (p.Y3565*), were identified in the USH2A gene, which showed co-segregation with the disease phenotype causing Usher syndrome type IIA in the recruited Chinese pedigree. The p.L150* variant was predicted to produce a truncated protein which lacked almost all the functional domains of USH2A, whereas the p.Y3565* variant is located in one of the fibronectin type 3 domains, resulting in the loss of several fibronectin type 3 domains at the C-terminus of USH2A by producing the truncated protein. It was shown that Ush2a mRNA expression levels were higher in the retina compared with those in the eye tissues (lens, sclera and cornea), uterus, ovary, breast, testis, spleen, kidney, liver, intestine, brain, skeletal muscle and blood. Additionally, the protein structure was shown to be highly conserved by comparing Homo sapiens USH2A to eight other species. To the best of our knowledge, the present study is the first to identify two novel pathogenic variants, c.T449G (p.L150*) and c.T10695A (p.Y3565*), in the USH2A gene in a patient with Usher syndrome type IIA, thereby expanding the known spectrums of USH2A causative mutations. The present discovery may assist in understanding the molecular pathogenesis underlying the development of RP and Usher syndrome type IIA, and in the development of diagnostic, therapeutic and genetic counseling strategies in patients with Usher syndrome type IIA disease.
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Affiliation(s)
- Jiewen Fu
- Key Laboratory of Epigenetics and Oncology, Research Center for Preclinical Medicine, Southwest Medical University, Luzhou, Sichuan 646000, P.R. China
| | - Jingliang Cheng
- Key Laboratory of Epigenetics and Oncology, Research Center for Preclinical Medicine, Southwest Medical University, Luzhou, Sichuan 646000, P.R. China
| | - Qi Zhou
- Department of Ophthalmology, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, P.R. China
| | - Md Asaduzzaman Khan
- Key Laboratory of Epigenetics and Oncology, Research Center for Preclinical Medicine, Southwest Medical University, Luzhou, Sichuan 646000, P.R. China
| | - Chengxia Duan
- Department of Ophthalmology, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, P.R. China
| | - Jiangzhou Peng
- Department of Thoracic Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong 510630, P.R. China
| | - Hongbin Lv
- Department of Ophthalmology, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, P.R. China
| | - Junjiang Fu
- Key Laboratory of Epigenetics and Oncology, Research Center for Preclinical Medicine, Southwest Medical University, Luzhou, Sichuan 646000, P.R. ChinaDepartment of Ophthalmology, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000
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SCAR marker for identification and discrimination of specific medicinal Lycium chinense Miller from Lycium species from ramp-PCR RAPD fragments. 3 Biotech 2020; 10:334. [PMID: 32656067 DOI: 10.1007/s13205-020-02325-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 06/29/2020] [Indexed: 12/19/2022] Open
Abstract
In the current study, ramp-PCR fragments from improved RAPD (random amplified polymorphic DNA) amplification of Lycium (Goji) species or cultivars were cut and cloned into the vector of pGEM-T. A positive clone 10-5 was screened by PCR amplification, enzymatic digestion, and Sanger sequencing. A SCAR (sequence-characterized amplified region) marker, named Goji 10-5, with 949 nucleotides in length, was identified. Goji 10-5 is specific to Goji species Lycium chinense Miller from Jiangxi in China and Texas in the USA. A BLAST search of this nucleotide sequence in the GenBank database indicated that it shows no identity with any other species, including no any other Lycium species. As a new sequence, we have deposited it in the GenBank database with accession No. MN862323. PCR assays were developed and converted the nucleotide sequence to become a novel molecular marker for Lycium chinense Miller, named Goji 10-5. This marker may be used for the genetic identification of other samples. This study has successfully developed Goji 10-5, a specific SCAR marker to identify L. chinense and distinguish it from other species, including other Lycium species from different locations.
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Expressions and significances of the angiotensin-converting enzyme 2 gene, the receptor of SARS-CoV-2 for COVID-19. Mol Biol Rep 2020; 47:4383-4392. [PMID: 32410141 PMCID: PMC7224351 DOI: 10.1007/s11033-020-05478-4] [Citation(s) in RCA: 116] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 04/28/2020] [Indexed: 12/28/2022]
Abstract
The ACE2 gene is a receptor of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) for COVID-19 (coronavirus disease 2019). To analyze the expression profiles and clinical significances for this gene in humans, RNA-seq data representing 27 different tissues were analyzed using NCBI; total RNA was extracted from different tissues of mouse and semi-quantitative reverse transcriptional-polymerase chain reaction (Q-RT-PCR) was carried out. Immunohistochemistry expression profiles in normal tissues and cancer tissues and TCGA survival analysis in renal and liver cancer were conducted. ACE2 was highly conserved in different species. In normal tissues, ACE2 expression distributions were organ-specific, mainly in the kidney, male testis and female breast, and cardiovascular and gastrointestinal systems. High level of expression in testis, cardiovascular and gastrointestinal system indicated that SARS-CoV-2 might not only attack the lungs, but also affect other organs, particularly the testes, thus it may severely damage male sexual development for younger male and lead to infertility in an adult male, if he contracted COVID-19. On the other side, high expression of ACE2 was correlated with increased survival rate in renal and liver cancer, indicating that ACE2 is a prognostic marker in both renal cancer and liver cancers. Thus, the ACE2 is a functional receptor for SARS-CoV-2 and has a potential anti-tumor role in cancer. Taken together, this study may not only provide potential clues for further medical pathogenesis of COVID-19 and male fertility, but also indicate the clinical significance of the role of the ACE2 gene in cancer.
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