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Ilyas M, Tariq F, Ishaq R, Habiba U, Bibi F, Khan SN, Ali Y, Haider S, Efthymiou S, Abdullah U, Raja GK, Shaiq PA. Whole exome sequencing identifies variable expressivity of CLN6 variants in Progressive myoclonic epilepsy affected families. Epilepsy Res 2024; 201:107283. [PMID: 38382230 DOI: 10.1016/j.eplepsyres.2023.107283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 11/25/2023] [Accepted: 12/14/2023] [Indexed: 02/23/2024]
Abstract
Progressive myoclonic epilepsies (PMEs) are a group of neurodegenerative disorders, predominantly affecting adolescents and, characterized by generalized worsening myoclonus epilepsies, ataxia, cognitive deficits, and dementia. To date, several genes, having implications in diverse phenotypic expressions associated with PMEs, have been identified. Genetic diagnosis is available for most of the adolescence-onset myoclonic epilepsies. This study aimed to elucidate the genetic basis of PMEs in three multiplex Pakistani families exhibiting clinically variable phenotypes. Causative variant(s) in the studied families, and mode of segregation were identified by Whole Exome Sequencing (WES) of the probands, followed by bi-directional Sanger sequencing for final validation. We identified homozygous recessive CLN6 missense variant c.768 C>G (p.Asp256Glu) in Family 1, and c.889 C>A (p.Pro297Thr) variant in Family 2. While in Family 3, we found a homozygous variant (c.316dup) that caused a frameshift mutation, leading to a premature stop codon in the CLN6 protein, resulting in a truncated protein (p.Arg106ProfsTer26). Though CLN6 is previously identified to underlie late infantile and adolescent onset neuronal ceroid lipofuscinosis, this study supports and expands the phenotypic spectrum of CLN6 mutations and signifies diagnositc potential CLN6 variants for PMEs. Diverse pathological effects of variant c .768 C>G were observed in Family 1, with same genotypes, suggesting clinical heterogeneity and/or variable expressivity that might be the implication of pleiotropic effects of the gene in these cases.
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Affiliation(s)
- Muhammad Ilyas
- University Institute of Biochemistry and Biotechnology, (PMAS) Pir Mehr Ali Shah Arid Agriculture University Rawalpindi, Pakistan; Department of Medical Laboratory Technology, Riphah International University, Malakand Campus, Khyber Pakhtunkhwa, Pakistan
| | - Faiza Tariq
- University Institute of Biochemistry and Biotechnology, (PMAS) Pir Mehr Ali Shah Arid Agriculture University Rawalpindi, Pakistan
| | - Rafaqat Ishaq
- University Institute of Biochemistry and Biotechnology, (PMAS) Pir Mehr Ali Shah Arid Agriculture University Rawalpindi, Pakistan
| | - Umme Habiba
- University Institute of Biochemistry and Biotechnology, (PMAS) Pir Mehr Ali Shah Arid Agriculture University Rawalpindi, Pakistan
| | - Farah Bibi
- University Institute of Biochemistry and Biotechnology, (PMAS) Pir Mehr Ali Shah Arid Agriculture University Rawalpindi, Pakistan
| | - Sadiq Noor Khan
- Department of Medical Laboratory Technology, University of Haripur, Khyber Pakhtunkhwa, Pakistan
| | - Yasir Ali
- Institute of Chemistry, Solvak Academy of Sciences, 84538 Bratislava, Slovakia
| | - Shehzad Haider
- Wah Medical College, Izzat Ali Shah Hospital, Maternal and Child Health Centre, Wah Cantt, Pakistan
| | | | - Uzma Abdullah
- University Institute of Biochemistry and Biotechnology, (PMAS) Pir Mehr Ali Shah Arid Agriculture University Rawalpindi, Pakistan
| | - Ghazala Kaukab Raja
- University Institute of Biochemistry and Biotechnology, (PMAS) Pir Mehr Ali Shah Arid Agriculture University Rawalpindi, Pakistan
| | - Pakeeza Arzoo Shaiq
- University Institute of Biochemistry and Biotechnology, (PMAS) Pir Mehr Ali Shah Arid Agriculture University Rawalpindi, Pakistan.
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Liao WP. Epilepsy-associated genes: discovery, clinical significance, and underlying principles of genetic medicine. Seizure 2024; 116:1-3. [PMID: 38245481 DOI: 10.1016/j.seizure.2024.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 01/01/2024] [Accepted: 01/02/2024] [Indexed: 01/22/2024] Open
Affiliation(s)
- Wei-Ping Liao
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, Guangdong, China.
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