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Sundarrajan S, Venkatesan A, Kumar S U, Gopikrishnan M, Tayubi IA, Aditya M, Siddaiah GB, George Priya Doss C, Zayed H. Exome sequence analysis of rare frequency variants in Late-Onset Alzheimer Disease. Metab Brain Dis 2023; 38:2025-2036. [PMID: 37162726 PMCID: PMC10348954 DOI: 10.1007/s11011-023-01221-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 04/19/2023] [Indexed: 05/11/2023]
Abstract
Alzheimer disease (AD) is a leading cause of dementia in elderly patients who continue to live between 3 and 11 years of diagnosis. A steep rise in AD incidents is observed in the elderly population in East-Asian countries. The disease progresses through several changes, including memory loss, behavioural issues, and cognitive impairment. The etiology of AD is hard to determine because of its complex nature. The whole exome sequences of late-onset AD (LOAD) patients of Korean origin are investigated to identify rare genetic variants that may influence the complex disorder. Computational annotation was performed to assess the function of candidate variants in LOAD. The in silico pathogenicity prediction tools such as SIFT, Polyphen-2, Mutation Taster, CADD, LRT, PROVEAN, DANN, VEST3, fathmm-MKL, GERP + + , SiPhy, phastCons, and phyloP identified around 17 genes harbouring deleterious variants. The variants in the ALDH3A2 and RAD54B genes were pathogenic, while in 15 other genes were predicted to be variants of unknown significance. These variants can be potential risk candidates contributing to AD. In silico computational techniques such as molecular docking, molecular dynamic simulation and steered molecular dynamics were carried out to understand the structural insights of RAD54B with ATP. The simulation of mutant (T459N) RAD54B with ATP revealed reduced binding strength of ATP at its binding site. In addition, lower binding free energy was observed when compared to the wild-type RAD54B. Our study shows that the identified uncommon variants are linked to AD and could be probable predisposing genetic factors of LOAD.
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Affiliation(s)
| | - Arthi Venkatesan
- BIOVIA Specialist, VIAS 3D, MG Road, Bengaluru, 560001, Karnataka, India
| | - Udhaya Kumar S
- Laboratory of Integrative Genomics, Department of Integrative Biology, School of BioSciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India
| | - Mohanraj Gopikrishnan
- Laboratory of Integrative Genomics, Department of Integrative Biology, School of BioSciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India
| | - Iftikhar Aslam Tayubi
- Department of Computer Science, Faculty of Computing and Information Technology, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
| | - M Aditya
- Department of Biotechnology, Siddaganga Institute of Technology, Tumkur, Karnataka, 572103, India
| | | | - C George Priya Doss
- Laboratory of Integrative Genomics, Department of Integrative Biology, School of BioSciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India.
| | - Hatem Zayed
- Department of Biomedical Sciences College of Health Sciences, QU Health, Qatar University, Doha, Qatar.
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Biler ED, Ilim O, Onay H, Uretmen O. CHN1 gene mutation analysis in patients with Duane retraction syndrome. J AAPOS 2017; 21:472-475.e2. [PMID: 29031989 DOI: 10.1016/j.jaapos.2017.07.208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 07/10/2017] [Accepted: 07/20/2017] [Indexed: 01/17/2023]
Abstract
PURPOSE To investigate CHN1 (chimerin 1) gene mutations in patients with isolated nonsyndromic Duane syndrome and accompanying positive familial history, bilaterality, or various systemic disorders. METHODS Patients with Duane retraction syndrome (DRS) and a positive family history of congenital ocular motility disturbance or bilateral involvement or accompanying any congenital disorder(s) seen consecutively at a single center from 2013 to 2016 were enrolled. All subjects underwent full ophthalmologic examination, including refraction, best-corrected visual acuity, ocular alignment and motility, globe retraction, and biomicroscopic or fundus evaluation. DNA samples were investigated by direct sequencing of the coding regions of the CHN1 gene. RESULTS A total of 30 patients (15 males) were included (mean age, 11.8 ± 10.4 years; range, 2-45 years): 8 cases presented with bilateral DRS; 22, with unilateral DRS. Family history of ocular motility abnormality was positive in 16 patients. Eleven cases had an additional congenital disorder. In 2 patients, 2 different mutations were detected in the CHN1 gene: p.E313K (c.937G>A) and p.N224S (c.671A>G). CONCLUSIONS CHN1 mutations were identified in 2 bilateral cases and in 1 parent of 1 affected case. One mutation is novel and occurred with additional vertical gaze abnormalities. Additional genetic studies evaluating chimerin 1 (CHN1) and its role in the development of the ocular motor axis are needed to provide new data about these mutations and phenotypic variations.
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Affiliation(s)
| | - Orhan Ilim
- Department of Ophthalmology, Ege University Faculty of Medicine, Izmir, Turkey
| | - Huseyin Onay
- Department of Molecular Genetics, Ege University Faculty of Medicine, Izmir, Turkey
| | - Onder Uretmen
- Department of Ophthalmology, Ege University Faculty of Medicine, Izmir, Turkey
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Abu-Amero KK, Kondkar AA, Khan AO. A microdeletion in the GRHL2 Gene in two unrelated patients with congenital fibrosis of the extra ocular muscles. BMC Res Notes 2017; 10:562. [PMID: 29110737 PMCID: PMC5674732 DOI: 10.1186/s13104-017-2888-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 10/31/2017] [Indexed: 12/13/2022] Open
Abstract
Objective Congenital fibrosis of the extraocular muscles type 1 (CFEOM1) is known to be caused by mutations in KIF21A or TUBB3 or other known genes (SALL4, CHN1, HOXA1). However, affected children may harbor other genetic defects. Therefore, a candidate gene analysis (KIF21A, TUBB3 SALL4, CHN1, HOXA1) and a high-resolution array comparative genomic hybridization (arrayCGH) was performed in two unrelated children with sporadic CFEOM1. Results Two unrelated Saudi patients did not have any mutation(s) after sequencing the full coding regions of SALL4, CHN1, HOXA1, and TUBB3 genes; and exons 8, 20, and 21 of the KIF21A gene. However, arrayCGH revealed a 3.17 Kb deletion at chromosome 8p22 with copy number state equal to 1, indicating a heterozygous deletion. This deletion was absent in proband’s mother or father or 220 unrelated healthy individuals of similar ethnicity. The deletion encompassed only one functional gene, GRHL2, which encodes a transcription factor. In humans, defects in this gene are a cause of non-syndromic sensorineural deafness, autosomal dominant type 28 (DFNA28). We speculate that GRHL2 gene may have a role in orbital innervations and the defect in this gene (deletion) may be related to the CFEOM1 phenotype in these two children.
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Affiliation(s)
- Khaled K Abu-Amero
- Glaucoma Research Chair, Department of Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia. .,Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, 60612, USA.
| | - Altaf A Kondkar
- Glaucoma Research Chair, Department of Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Arif O Khan
- Division of Pediatric Ophthalmology, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.,Eye Institute, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates
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