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Zhang Y, Bi C, Nadeef S, Maddirevula S, Alqahtani M, Alkuraya FS, Li M. NanoRanger enables rapid single-base-pair resolution of genomic disorders. MED 2024:S2666-6340(24)00262-9. [PMID: 39047733 DOI: 10.1016/j.medj.2024.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Revised: 04/13/2024] [Accepted: 07/01/2024] [Indexed: 07/27/2024]
Abstract
BACKGROUND Delineating base-resolution breakpoints of complex rearrangements is crucial for an accurate clinical understanding of pathogenic variants and for carrier screening within family networks or the broader population. However, despite advances in genetic testing using short-read sequencing (SRS), this task remains costly and challenging. METHODS This study addresses the challenges of resolving missing disease-causing breakpoints in complex genomic disorders with suspected homozygous rearrangements by employing multiple long-read sequencing (LRS) strategies, including a novel and efficient strategy named nanopore-based rapid acquisition of neighboring genomic regions (NanoRanger). NanoRanger does not require large amounts of ultrahigh-molecular-weight DNA and stands out for its ease of use and rapid acquisition of large genomic regions of interest with deep coverage. FINDINGS We describe a cohort of 16 familial cases, each harboring homozygous rearrangements that defied breakpoint determination by SRS and optical genome mapping (OGM). NanoRanger identified the breakpoints with single-base-pair resolution, enabling accurate determination of the carrier status of unaffected family members as well as the founder nature of these genomic lesions and their frequency in the local population. The resolved breakpoints revealed that repetitive DNA, gene regulatory elements, and transcription activity contribute to genome instability in these novel recessive rearrangements. CONCLUSIONS Our data suggest that NanoRanger greatly improves the success rate of resolving base-resolution breakpoints of complex genomic disorders and expands access to LRS for the benefit of patients with Mendelian disorders. FUNDING M.L. is supported by KAUST Baseline Award no. BAS/1/1080-01-01 and KAUST Research Translation Fund Award no. REI/1/4742-01.
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Affiliation(s)
- Yingzi Zhang
- Bioscience Program, Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Chongwei Bi
- Bioscience Program, Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Seba Nadeef
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Sateesh Maddirevula
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Mashael Alqahtani
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Fowzan S Alkuraya
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia; Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia.
| | - Mo Li
- Bioscience Program, Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia; Bioengineering Program, Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
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2
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AlAbdi L, Rahbeeni Z, Maddirevula S, Helaby R, Abdulwahab F, Khan AO, Riley LG, Alhashem A, Chassaing N, Jamieson RV, Alkuraya FS. A founder variant expands the phenotype of WNT7B-related PDAC syndrome. Clin Genet 2024; 106:66-71. [PMID: 38417950 DOI: 10.1111/cge.14512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 01/22/2024] [Accepted: 02/15/2024] [Indexed: 03/01/2024]
Abstract
Pulmonary hypoplasia, Diaphragmatic anomalies, Anophthalmia/microphthalmia, and Cardiac defects (PDAC) syndrome is a genetically heterogeneous multiple congenital malformation syndrome. Although pathogenic variants in RARB and STRA6 are established causes of PDAC, many PDAC cases remain unsolved at the molecular level. Recently, we proposed biallelic WNT7B variants as a novel etiology based on several families with typical features of PDAC syndrome albeit with variable expressivity. Here, we report three patients from two families that share a novel founder variant in WNT7B (c.739C > T; Arg247Trp). The phenotypic expression of this variant ranges from typical PDAC features to isolated genitourinary anomalies. Similar to previously reported PDAC-associated WNT7B variants, this variant was found to significantly impair WNT7B signaling activity further corroborating its proposed pathogenicity. This report adds further evidence to WNT7B-related PDAC and expands its variable expressivity.
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Affiliation(s)
- Lama AlAbdi
- Department of Zoology, Collage of Science, King Saud University, Riyadh, Saudi Arabia
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Zuhair Rahbeeni
- Department of Medical Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Sateesh Maddirevula
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Rana Helaby
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Firdous Abdulwahab
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Arif O Khan
- Eye Institute, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, USA
| | - Lisa G Riley
- Rare Diseases Functional Genomics, Kids Research, The Children's Hospital at Westmead and The Children's Medical Research Institute, Sydney, New South Wales, Australia
- Specialty of Child & Adolescent Health, Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Amal Alhashem
- Division of Clinical Genetic and Metabolic Medicine, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
- Department of Genetic and Metabolic, Sehha Virtual Hospital, Ministry of Health, Riyadh, Saudi Arabia
| | - Nicolas Chassaing
- Centre de Référence des Affections Rares en Génétique Ophtalmologique CARGO, Site Constitutif, Purpan University Hospital, Toulouse, Midi-Pyrénées, France
- Department of Medical Genetics, Purpan University Hospital, Toulouse, Midi-Pyrénées, France
| | - Robyn V Jamieson
- Eye Genetics Research Unit, Children's Medical Research Institute, University of Sydney; The Children's Hospital at Westmead, Sydney Children's Hospitals Network; and Save Sight Institute, Sydney, New South Wales, Australia
- Specialty of Genomic Medicine, Faculty of Medicine and Health and Child and Adolescent Health, University of Sydney, Sydney, New South Wales, Australia
| | - Fowzan S Alkuraya
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
- Division of Clinical Genetic and Metabolic Medicine, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
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3
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AlAbdi L, Neuhann T, Prott EC, Schön U, Abdulwahab F, Faqeih E, Alkuraya FS. Human ABL1 deficiency syndrome (HADS) is a recognizable syndrome distinct from ABL1-related congenital heart defects and skeletal malformations syndrome. Hum Genet 2024; 143:739-745. [PMID: 38743093 DOI: 10.1007/s00439-024-02677-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 05/04/2024] [Indexed: 05/16/2024]
Abstract
Germline gain of function variants in the oncogene ABL1 cause congenital heart defects and skeletal malformations (CHDSKM) syndrome. Whether a corresponding ABL1 deficiency disorder exists in humans remains unknown although developmental defects in mice deficient for Abl1 support this notion. Here, we describe two multiplex consanguineous families, each segregating a different homozygous likely loss of function variant in ABL1. The associated phenotype is multiple congenital malformations and distinctive facial dysmorphism that are opposite in many ways to CHDSKM. We suggest that a tight balance of ABL1 activity is required during embryonic development and that both germline gain of function and loss of function variants result in distinctively different allelic congenital malformation disorders.
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Affiliation(s)
- Lama AlAbdi
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | | | | | - Ulrike Schön
- MGZ Medizinisch Genetisches Zentrum, Munich, Germany
| | - Firdous Abdulwahab
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Eissa Faqeih
- Section of Medical Genetics, King Fahad Medical City, Children's Specialist Hospital, Riyadh, Saudi Arabia
| | - Fowzan S Alkuraya
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.
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4
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You M, Shamseldin HE, Fogle HM, Rushing BR, AlMalki RH, Jaafar A, Hashem M, Abdulwahab F, Rahman AMA, Krupenko NI, Alkuraya FS, Krupenko SA. Further delineation of the phenotypic and metabolomic profile of ALDH1L2-related neurodevelopmental disorder. Clin Genet 2024; 105:488-498. [PMID: 38193334 PMCID: PMC10990829 DOI: 10.1111/cge.14479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/22/2023] [Accepted: 12/28/2023] [Indexed: 01/10/2024]
Abstract
ALDH1L2, a mitochondrial enzyme in folate metabolism, converts 10-formyl-THF (10-formyltetrahydrofolate) to THF (tetrahydrofolate) and CO2. At the cellular level, deficiency of this NADP+-dependent reaction results in marked reduction in NADPH/NADP+ ratio and reduced mitochondrial ATP. Thus far, a single patient with biallelic ALDH1L2 variants and the phenotype of a neurodevelopmental disorder has been reported. Here, we describe another patient with a neurodevelopmental disorder associated with a novel homozygous missense variant in ALDH1L2, Pro133His. The variant caused marked reduction in the ALDH1L2 enzyme activity in skin fibroblasts derived from the patient as probed by 10-FDDF, a stable synthetic analog of 10-formyl-THF. Additional associated abnormalities in these fibroblasts include reduced NADPH/NADP+ ratio and pool of mitochondrial ATP, upregulated autophagy and dramatically altered metabolomic profile. Overall, our study further supports a link between ALDH1L2 deficiency and abnormal neurodevelopment in humans.
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Affiliation(s)
- Mikyoung You
- UNC Nutrition Research Institute, Kannapolis, NC, USA
| | - Hanan E. Shamseldin
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center (KFSHRC), Riyadh, Saudi Arabia
| | - Halle M. Fogle
- UNC Nutrition Research Institute, Kannapolis, NC, USA
- Department of Nutrition, University of North Carolina-Chapel Hill, NC, USA
| | - Blake R. Rushing
- UNC Nutrition Research Institute, Kannapolis, NC, USA
- Department of Nutrition, University of North Carolina-Chapel Hill, NC, USA
| | - Reem H. AlMalki
- Metabolomics Section, Department of Clinical Genomics, Center for Genome Medicine, King Faisal Specialist Hospital and Research Center (KFSHRC), Riyadh, Saudi Arabia
| | - Amal Jaafar
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center (KFSHRC), Riyadh, Saudi Arabia
| | - Mais Hashem
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center (KFSHRC), Riyadh, Saudi Arabia
| | - Firdous Abdulwahab
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center (KFSHRC), Riyadh, Saudi Arabia
| | - Anas M. Abdel Rahman
- Metabolomics Section, Department of Clinical Genomics, Center for Genome Medicine, King Faisal Specialist Hospital and Research Center (KFSHRC), Riyadh, Saudi Arabia
- Department of Biochemistry and Molecular Medicine, College of Medicine, Al Faisal University, Riyadh, Saudi Arabia
| | - Natalia I. Krupenko
- UNC Nutrition Research Institute, Kannapolis, NC, USA
- Department of Nutrition, University of North Carolina-Chapel Hill, NC, USA
| | - Fowzan S. Alkuraya
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center (KFSHRC), Riyadh, Saudi Arabia
| | - Sergey A. Krupenko
- UNC Nutrition Research Institute, Kannapolis, NC, USA
- Department of Nutrition, University of North Carolina-Chapel Hill, NC, USA
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5
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AlAbdi L, Shamseldin HE, Khouj E, Helaby R, Aljamal B, Alqahtani M, Almulhim A, Hamid H, Hashem MO, Abdulwahab F, Abouyousef O, Jaafar A, Alshidi T, Al-Owain M, Alhashem A, Al Tala S, Khan AO, Mardawi E, Alkuraya H, Faqeih E, Afqi M, Alkhalifi S, Rahbeeni Z, Hagos ST, Al-Ahmadi W, Nadeef S, Maddirevula S, Khabar KSA, Putra A, Angelov A, Park C, Reyes-Ramos AM, Umer H, Ullah I, Driguez P, Fukasawa Y, Cheung MS, Gallouzi IE, Alkuraya FS. Beyond the exome: utility of long-read whole genome sequencing in exome-negative autosomal recessive diseases. Genome Med 2023; 15:114. [PMID: 38098057 PMCID: PMC10720148 DOI: 10.1186/s13073-023-01270-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 12/05/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND Long-read whole genome sequencing (lrWGS) has the potential to address the technical limitations of exome sequencing in ways not possible by short-read WGS. However, its utility in autosomal recessive Mendelian diseases is largely unknown. METHODS In a cohort of 34 families in which the suspected autosomal recessive diseases remained undiagnosed by exome sequencing, lrWGS was performed on the Pacific Bioscience Sequel IIe platform. RESULTS Likely causal variants were identified in 13 (38%) of the cohort. These include (1) a homozygous splicing SV in TYMS as a novel candidate gene for lethal neonatal lactic acidosis, (2) a homozygous non-coding SV that we propose impacts STK25 expression and causes a novel neurodevelopmental disorder, (3) a compound heterozygous SV in RP1L1 with complex inheritance pattern in a family with inherited retinal disease, (4) homozygous deep intronic variants in LEMD2 and SNAP91 as novel candidate genes for neurodevelopmental disorders in two families, and (5) a promoter SNV in SLC4A4 causing non-syndromic band keratopathy. Surprisingly, we also encountered causal variants that could have been identified by short-read exome sequencing in 7 families. The latter highlight scenarios that are especially challenging at the interpretation level. CONCLUSIONS Our data highlight the continued need to address the interpretation challenges in parallel with efforts to improve the sequencing technology itself. We propose a path forward for the implementation of lrWGS sequencing in the setting of autosomal recessive diseases in a way that maximizes its utility.
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Affiliation(s)
- Lama AlAbdi
- Department of Zoology, Collage of Science, King Saud University, Riyadh, Saudi Arabia
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Hanan E Shamseldin
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Ebtissal Khouj
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Rana Helaby
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Bayan Aljamal
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Mashael Alqahtani
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Aisha Almulhim
- Department of Zoology, Collage of Science, King Saud University, Riyadh, Saudi Arabia
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Halima Hamid
- Department of Zoology, Collage of Science, King Saud University, Riyadh, Saudi Arabia
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Mais O Hashem
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Firdous Abdulwahab
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Omar Abouyousef
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Amal Jaafar
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Tarfa Alshidi
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Mohammed Al-Owain
- Department of Medical Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
- Collage of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Amal Alhashem
- Collage of Medicine, Alfaisal University, Riyadh, Saudi Arabia
- Pediatric Department, Division of Genetic and Metabolic Medicine, Prince Sultan Medical Military City, Riyadh, Saudi Arabia
| | - Saeed Al Tala
- Pediatric Department, Neonatal Unit, Armed Forces Hospital, Khamis Mushayt, Saudi Arabia
| | - Arif O Khan
- Eye Institute, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA
| | - Elham Mardawi
- Maternal Fetal Medicine, Security Forces Hospital Program, Riyadh, Saudi Arabia
| | - Hisham Alkuraya
- Vitreoretinal Surgery and Ocular Genetics, Global Eye Care/Specialized Medical Center Hospital, Riyadh, Saudi Arabia
| | - Eissa Faqeih
- Section of Medical Genetics, King Fahad Medical City, Children's Specialist Hospital, Riyadh, Saudi Arabia
| | - Manal Afqi
- Metabolic and Genetic Center, King Salman Bin Abdulaziz Medical City, Almadinah Almunwarah, Saudi Arabia
| | - Salwa Alkhalifi
- Newborn Screening, Ministry of Health, Eastern Province, Saudi Arabia
| | - Zuhair Rahbeeni
- Department of Medical Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Samya T Hagos
- Department of Clinical Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Wijdan Al-Ahmadi
- Department of Molecular Biomedicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Seba Nadeef
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Sateesh Maddirevula
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Khalid S A Khabar
- Department of Molecular Biomedicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Alexander Putra
- King Abdullah University of Science and Technology (KAUST), Core Labs, Thuwal, Saudi Arabia
| | - Angel Angelov
- King Abdullah University of Science and Technology (KAUST), Core Labs, Thuwal, Saudi Arabia
| | - Changsook Park
- King Abdullah University of Science and Technology (KAUST), Core Labs, Thuwal, Saudi Arabia
| | - Ana M Reyes-Ramos
- King Abdullah University of Science and Technology (KAUST), Core Labs, Thuwal, Saudi Arabia
| | - Husen Umer
- King Abdullah University of Science and Technology (KAUST), Core Labs, Thuwal, Saudi Arabia
| | - Ikram Ullah
- King Abdullah University of Science and Technology (KAUST), Core Labs, Thuwal, Saudi Arabia
| | - Patrick Driguez
- King Abdullah University of Science and Technology (KAUST), Core Labs, Thuwal, Saudi Arabia
| | - Yoshinori Fukasawa
- King Abdullah University of Science and Technology (KAUST), Core Labs, Thuwal, Saudi Arabia
| | - Ming Sin Cheung
- King Abdullah University of Science and Technology (KAUST), Core Labs, Thuwal, Saudi Arabia
| | - Imed Eddine Gallouzi
- KAUST Smart-Health Initiative King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
- Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Fowzan S Alkuraya
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.
- KAUST Smart-Health Initiative King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
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6
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Lin SJ, Vona B, Lau T, Huang K, Zaki MS, Aldeen HS, Karimiani EG, Rocca C, Noureldeen MM, Saad AK, Petree C, Bartolomaeus T, Abou Jamra R, Zifarelli G, Gotkhindikar A, Wentzensen IM, Liao M, Cork EE, Varshney P, Hashemi N, Mohammadi MH, Rad A, Neira J, Toosi MB, Knopp C, Kurth I, Challman TD, Smith R, Abdalla A, Haaf T, Suri M, Joshi M, Chung WK, Moreno-De-Luca A, Houlden H, Maroofian R, Varshney GK. Evaluating the association of biallelic OGDHL variants with significant phenotypic heterogeneity. Genome Med 2023; 15:102. [PMID: 38031187 PMCID: PMC10688095 DOI: 10.1186/s13073-023-01258-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 11/13/2023] [Indexed: 12/01/2023] Open
Abstract
BACKGROUND Biallelic variants in OGDHL, encoding part of the α-ketoglutarate dehydrogenase complex, have been associated with highly heterogeneous neurological and neurodevelopmental disorders. However, the validity of this association remains to be confirmed. A second OGDHL patient cohort was recruited to carefully assess the gene-disease relationship. METHODS Using an unbiased genotype-first approach, we screened large, multiethnic aggregated sequencing datasets worldwide for biallelic OGDHL variants. We used CRISPR/Cas9 to generate zebrafish knockouts of ogdhl, ogdh paralogs, and dhtkd1 to investigate functional relationships and impact during development. Functional complementation with patient variant transcripts was conducted to systematically assess protein functionality as a readout for pathogenicity. RESULTS A cohort of 14 individuals from 12 unrelated families exhibited highly variable clinical phenotypes, with the majority of them presenting at least one additional variant, potentially accounting for a blended phenotype and complicating phenotypic understanding. We also uncovered extreme clinical heterogeneity and high allele frequencies, occasionally incompatible with a fully penetrant recessive disorder. Human cDNA of previously described and new variants were tested in an ogdhl zebrafish knockout model, adding functional evidence for variant reclassification. We disclosed evidence of hypomorphic alleles as well as a loss-of-function variant without deleterious effects in zebrafish variant testing also showing discordant familial segregation, challenging the relationship of OGDHL as a conventional Mendelian gene. Going further, we uncovered evidence for a complex compensatory relationship among OGDH, OGDHL, and DHTKD1 isoenzymes that are associated with neurodevelopmental disorders and exhibit complex transcriptional compensation patterns with partial functional redundancy. CONCLUSIONS Based on the results of genetic, clinical, and functional studies, we formed three hypotheses in which to frame observations: biallelic OGDHL variants lead to a highly variable monogenic disorder, variants in OGDHL are following a complex pattern of inheritance, or they may not be causative at all. Our study further highlights the continuing challenges of assessing the validity of reported disease-gene associations and effects of variants identified in these genes. This is particularly more complicated in making genetic diagnoses based on identification of variants in genes presenting a highly heterogenous phenotype such as "OGDHL-related disorders".
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Affiliation(s)
- Sheng-Jia Lin
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
| | - Barbara Vona
- Institute of Human Genetics, Julius Maximilians University Würzburg, Würzburg, Germany
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
- Department of Otolaryngology-Head and Neck Surgery, Tübingen Hearing Research Center, Eberhard Karls University, Tübingen, 72076, Germany
| | - Tracy Lau
- Department of Neuromuscular Disorders, Queen Square Institute of Neurology, University College London, London, UK
| | - Kevin Huang
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
| | - Maha S Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | - Huda Shujaa Aldeen
- Department of Neuromuscular Disorders, Queen Square Institute of Neurology, University College London, London, UK
| | - Ehsan Ghayoor Karimiani
- Molecular and Clinical Sciences Institute, St. George's, University of London, Cranmer Terrace London, London, UK
| | - Clarissa Rocca
- Department of Neuromuscular Disorders, Queen Square Institute of Neurology, University College London, London, UK
| | - Mahmoud M Noureldeen
- Department of Pediatrics, Faculty of Medicine, Beni-Suef University, Beni-Suef, Egypt
| | - Ahmed K Saad
- Medical Molecular Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | - Cassidy Petree
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
| | - Tobias Bartolomaeus
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Rami Abou Jamra
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | | | | | | | | | - Emalyn Elise Cork
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Pratishtha Varshney
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
| | - Narges Hashemi
- Department of Pediatrics, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Aboulfazl Rad
- Department of Otolaryngology-Head and Neck Surgery, Tübingen Hearing Research Center, Eberhard Karls University, Tübingen, 72076, Germany
| | - Juanita Neira
- Department of Human Genetics, Emory University, Atlanta, GA, 30322, USA
| | - Mehran Beiraghi Toosi
- Department of Pediatrics, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Cordula Knopp
- Institute for Human Genetics and Genomic Medicine, RWTH Aachen University, Pauwelsstr. 30, Aachen, 52074, Germany
| | - Ingo Kurth
- Institute for Human Genetics and Genomic Medicine, RWTH Aachen University, Pauwelsstr. 30, Aachen, 52074, Germany
| | - Thomas D Challman
- Autism & Developmental Medicine Institute, Geisinger, Lewisburg, PA, USA
| | - Rebecca Smith
- Autism & Developmental Medicine Institute, Geisinger, Lewisburg, PA, USA
| | - Asmahan Abdalla
- Department of Pediatric Endocrinology, Gaafar Ibn Auf Children's Tertiary Hospital, Khartoum, Sudan
| | - Thomas Haaf
- Institute of Human Genetics, Julius Maximilians University Würzburg, Würzburg, Germany
| | - Mohnish Suri
- Nottingham Clinical Genetics Service, Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - Manali Joshi
- Bioinformatics Centre, S. P. Pune University, Pune, India
| | - Wendy K Chung
- Department of Pediatrics, Boston Children's Hospitaland, Harvard Medical School , Boston, MA, USA
| | - Andres Moreno-De-Luca
- Department of Diagnostic Radiology, Kingston Health Sciences Centre, Queen's University, Kingston, ON, Canada
| | - Henry Houlden
- Department of Neuromuscular Disorders, Queen Square Institute of Neurology, University College London, London, UK
| | - Reza Maroofian
- Department of Neuromuscular Disorders, Queen Square Institute of Neurology, University College London, London, UK.
| | - Gaurav K Varshney
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA.
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