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Jeyabalan N, Ghosh A, Mathias GP, Ghosh A. Rare eye diseases in India: A concise review of genes and genetics. Indian J Ophthalmol 2022; 70:2232-2238. [PMID: 35791102 PMCID: PMC9426079 DOI: 10.4103/ijo.ijo_322_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Rare eye diseases (REDs) are mostly progressive and are the leading cause of irreversible blindness. The disease onset can vary from early childhood to late adulthood. A high rate of consanguinity contributes to India’s predisposition to RED. Most gene variations causing REDs are monogenic and, in some cases, digenic. All three types of Mendelian inheritance have been reported in REDs. Some of the REDs are related to systemic illness with variable phenotypes in affected family members. Approximately, 50% of the children affected by REDs show associated phenotypes at the early stages of the disease. A precise clinical diagnosis becomes challenging due to high clinical and genetic heterogeneity. Technological advances, such as next-generation sequencing (NGS), have improved genetic and genomic testing for REDs, thereby aiding in determining the underlying causative gene variants. It is noteworthy that genetic testing together with genetic counseling facilitates a more personalized approach in the accurate diagnosis and management of the disease. In this review, we discuss REDs identified in the Indian population and their underlying genetic etiology.
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Affiliation(s)
- Nallathambi Jeyabalan
- Molecular Signaling and Gene Therapy Unit, GROW Research Laboratory, Narayana Nethralaya Foundation, Narayana Nethralaya Eye Hospital, Bengaluru, Karnataka, India
| | - Anuprita Ghosh
- Molecular Signaling and Gene Therapy Unit, GROW Research Laboratory, Narayana Nethralaya Foundation, Narayana Nethralaya Eye Hospital, Bengaluru, Karnataka, India
| | - Grace P Mathias
- Molecular Signaling and Gene Therapy Unit, GROW Research Laboratory, Narayana Nethralaya Foundation, Narayana Nethralaya Eye Hospital, Bengaluru, Karnataka, India
| | - Arkasubhra Ghosh
- Molecular Signaling and Gene Therapy Unit, GROW Research Laboratory, Narayana Nethralaya Foundation, Narayana Nethralaya Eye Hospital, Bengaluru, Karnataka, India
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Kannabiran C, Parameswarappa D, Jalali S. Genetics of Inherited Retinal Diseases in Understudied Populations. Front Genet 2022; 13:858556. [PMID: 35295952 PMCID: PMC8919366 DOI: 10.3389/fgene.2022.858556] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 02/03/2022] [Indexed: 11/17/2022] Open
Abstract
Retinitis pigmentosa is one of the major forms of inherited retinal dystrophy transmitted in all Mendelian and non-Mendelian forms of inheritance. It involves the loss of retinal photoreceptor cells with severe loss of vision or blindness within the first 2 decades of life. RP occurs at a relatively high prevalence in India and is often associated with consanguinity in certain South Asian communities where this practice is customary. This review describes the studies that have been published with regard to genetics of retinitis pigmentosa in India and neighboring South Asian countries. These populations have been understudied in these aspects although to a variable degree from one country to another. Genetic studies on RP in India have been carried out with a range of methods aimed at detecting specific mutations, to screening of candidate genes or selected genomic regions, homozygosity mapping to whole genome sequencing. These efforts have led to a molecular genetic characterization of RP in Indian families. Similar studies on large extended families from Pakistan have provided insight into several novel genes underlying the pathogenesis of these diseases. The extreme degree of clinical and genetic heterogeneity of RP renders it challenging to identify the associated genes in these populations, and to translate the research output towards better management of the disease, as there are no unifying genetic features that are characteristic of any population so far.
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Affiliation(s)
- Chitra Kannabiran
- Kallam Anji Reddy Molecular Genetics Laboratory, Prof Brien Holden Eye Research Centre, Hyderabad, India.,L. V. Prasad Eye Institute, Hyderabad, India
| | - Deepika Parameswarappa
- L. V. Prasad Eye Institute, Hyderabad, India.,Smt Kannuri Santhamma Centre for Retina Vitreous Services, Hyderabad, India
| | - Subhadra Jalali
- L. V. Prasad Eye Institute, Hyderabad, India.,Smt Kannuri Santhamma Centre for Retina Vitreous Services, Hyderabad, India
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Bansal M, Tandon R, Saxena R, Sharma A, Sen S, Kishore A, Venkatesh P, Maiti S, Chakraborty D. Ophthalmic genetics practice and research in India: Vision in 2020. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2020; 184:718-727. [PMID: 32865332 DOI: 10.1002/ajmg.c.31827] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/19/2020] [Accepted: 07/28/2020] [Indexed: 12/13/2022]
Abstract
Ophthalmic genetics is a much needed and growing area in India. Ethnic diversity, with a high degree of consanguinity, has led to a high prevalence of genetic disorders in the country. As the second most populous country in the world, this naturally results in a significant number of affected people overall. Practice involves coherent association between ophthalmologists, genetic counselor and pediatricians. Eye genetics in India in recent times has witnessed advanced research using cutting edge diagnostics, next generation sequencing (NGS) approaches, stem cell therapies, gene therapy and genomic editing. This article will highlight the studies reporting genetic variations in the country, challenges in practice, and the latest advances in ophthalmic genetic research in India.
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Affiliation(s)
- Mayank Bansal
- Council for Scientific and Industrial Research (CSIR), Institute of Genomics and Integrative Biology (IGIB), New Delhi, India.,Academy of Scientific and Innovative Research (AcSIR), Delhi, India.,Department of Ophthalmology, Fortis Memorial Research Institute, Gurugram, India
| | - Radhika Tandon
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences (AIIMS), New Delhi, India
| | - Rohit Saxena
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences (AIIMS), New Delhi, India
| | - Arundhati Sharma
- Department of Anatomy, All India Institute of Medical Sciences (AIIMS), New Delhi, India
| | - Sagnik Sen
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences (AIIMS), New Delhi, India
| | - Alisha Kishore
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences (AIIMS), New Delhi, India
| | - Pradeep Venkatesh
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences (AIIMS), New Delhi, India
| | - Souvik Maiti
- Council for Scientific and Industrial Research (CSIR), Institute of Genomics and Integrative Biology (IGIB), New Delhi, India.,Academy of Scientific and Innovative Research (AcSIR), Delhi, India
| | - Debojyoti Chakraborty
- Council for Scientific and Industrial Research (CSIR), Institute of Genomics and Integrative Biology (IGIB), New Delhi, India.,Academy of Scientific and Innovative Research (AcSIR), Delhi, India
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Srikrupa N, Srilekha S, Sen P, Arokiasamy T, Meenakshi S, Bhende M, Kapur S, Soumittra N. Genetic profile and mutation spectrum of Leber congenital amaurosis in a larger Indian cohort using high throughput targeted re-sequencing. Clin Genet 2018; 93:329-339. [DOI: 10.1111/cge.13159] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 09/22/2017] [Accepted: 10/16/2017] [Indexed: 01/02/2023]
Affiliation(s)
- N.N. Srikrupa
- SNONGC Department of Genetics and Molecular Biology; Vision Research Foundation; Chennai India
- PhD Scholar; Birla Institute of Technology & Science (BITS); Hyderabad India
| | - S. Srilekha
- SNONGC Department of Genetics and Molecular Biology; Vision Research Foundation; Chennai India
| | - P. Sen
- Department of Vitreo-Retinal Services; Medical Research Foundation; Chennai India
| | - T. Arokiasamy
- SNONGC Department of Genetics and Molecular Biology; Vision Research Foundation; Chennai India
| | - S. Meenakshi
- Department of Pediatric Ophthalmology; Medical Research Foundation; Chennai India
| | - M. Bhende
- Department of Vitreo-Retinal Services; Medical Research Foundation; Chennai India
| | - S. Kapur
- Department of Biological Sciences; Birla Institute of Technology & Science (BITS); Hyderabad India
| | - N. Soumittra
- SNONGC Department of Genetics and Molecular Biology; Vision Research Foundation; Chennai India
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Singh M, Tyagi SC. Genes and genetics in eye diseases: a genomic medicine approach for investigating hereditary and inflammatory ocular disorders. Int J Ophthalmol 2018; 11:117-134. [PMID: 29376001 DOI: 10.18240/ijo.2018.01.20] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 10/31/2017] [Indexed: 12/27/2022] Open
Abstract
Past 25y have witnessed an exponential increase in knowledge and understanding of ocular diseases and their respective genetic underpinnings. As a result, scientists have mapped many genes and their variants that can influence vision and health of our eyes. Based on these findings, it is becoming clear that an early diagnosis employing genetic testing can help evaluate patients' conditions for instituting treatment plan(s) and follow-up care to avoid vision complications later. For example, knowing family history becomes crucial for inherited eye diseases as it can benefit members in family who may have similar eye diseases or predispositions. Therefore, gathering information from an elaborate examination along with complete assessment of past medical illness by ophthalmologists followed by consultation with geneticists can help create a roadmap for making diagnosis and treatment precise and beneficial. In this review, we present an update on ocular genomic medicine that we believe has tremendous potential towards unraveling genetic implications in ocular diseases and patients' susceptibilities. We also discuss translational aspects of genetic ophthalmology and genome engineering that may help advance molecular diagnostics and therapeutics.
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Affiliation(s)
- Mahavir Singh
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
| | - Suresh C Tyagi
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
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Peng YQ, Tang LS, Yoshida S, Zhou YD. Applications of CRISPR/Cas9 in retinal degenerative diseases. Int J Ophthalmol 2017; 10:646-651. [PMID: 28503441 DOI: 10.18240/ijo.2017.04.23] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 03/09/2017] [Indexed: 02/06/2023] Open
Abstract
Gene therapy is a potentially effective treatment for retinal degenerative diseases. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system has been developed as a new genome-editing tool in ophthalmic studies. Recent advances in researches showed that CRISPR/Cas9 has been applied in generating animal models as well as gene therapy in vivo of retinitis pigmentosa (RP) and leber congenital amaurosis (LCA). It has also been shown as a potential attempt for clinic by combining with other technologies such as adeno-associated virus (AAV) and induced pluripotent stem cells (iPSCs). In this review, we highlight the main points of further prospect of using CRISPR/Cas9 in targeting retinal degeneration. We also emphasize the potential applications of this technique in treating retinal degenerative diseases.
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Affiliation(s)
- Ying-Qian Peng
- Department of Ophthalmology, the Second Xiangya Hospital, Central South University, Changsha 410011, Hunan Province, China
| | - Luo-Sheng Tang
- Department of Ophthalmology, the Second Xiangya Hospital, Central South University, Changsha 410011, Hunan Province, China
| | - Shigeo Yoshida
- Department of Ophthalmology, Kyushu University Graduate School of Medical Sciences, Fukuoka 812-8582, Japan
| | - Ye-Di Zhou
- Department of Ophthalmology, the Second Xiangya Hospital, Central South University, Changsha 410011, Hunan Province, China
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