1
|
Al Anazi AH, Ammar AS, Al-Hajj M, Cyrus C, Aljaafari D, Khoda I, Abdelfatah AK, Alsulaiman AA, Alanazi F, Alanazi R, Gandla D, Lad H, Barayan S, Keating BJ, Al-Ali AK. Whole-exome sequencing of a Saudi epilepsy cohort reveals association signals in known and potentially novel loci. Hum Genomics 2022; 16:71. [PMID: 36539902 PMCID: PMC9764464 DOI: 10.1186/s40246-022-00444-6] [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: 09/08/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Epilepsy, a serious chronic neurological condition effecting up to 100 million people globally, has clear genetic underpinnings including common and rare variants. In Saudi Arabia, the prevalence of epilepsy is high and caused mainly by perinatal and genetic factors. No whole-exome sequencing (WES) studies have been performed to date in Saudi Arabian epilepsy cohorts. This offers a unique opportunity for the discovery of rare genetic variants impacting this disease as there is a high rate of consanguinity among large tribal pedigrees. RESULTS We performed WES on 144 individuals diagnosed with epilepsy, to interrogate known epilepsy-related genes for known and functional novel variants. We also used an American College of Medical Genetics (ACMG) guideline-based variant prioritization approach in an attempt to discover putative causative variants. We identified 32 potentially causative pathogenic variants across 30 different genes in 44/144 (30%) of these Saudi epilepsy individuals. We also identified 232 variants of unknown significance (VUS) across 101 different genes in 133/144 (92%) subjects. Strong enrichment of variants of likely pathogenicity was observed in previously described epilepsy-associated loci, and a number of putative pathogenic variants in novel loci are also observed. CONCLUSION Several putative pathogenic variants in known epilepsy-related loci were identified for the first time in our population, in addition to several potential new loci which may be prioritized for further investigation.
Collapse
Affiliation(s)
- Abdulrahman H. Al Anazi
- grid.411975.f0000 0004 0607 035XDepartment of Neurosurgery, King Fahd Hospital of the University, Alkhobar, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Ahmed S. Ammar
- grid.411975.f0000 0004 0607 035XDepartment of Neurosurgery, King Fahd Hospital of the University, Alkhobar, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Mahmoud Al-Hajj
- grid.415296.d0000 0004 0607 1539Department of Neurosurgery, King Fahd Hospital, Alhafof, Saudi Arabia
| | - Cyril Cyrus
- grid.411975.f0000 0004 0607 035XDepartment of Clinical Biochemistry, College of Medicine, Imam Abdulrahman Bin Faisal University, P. O. Box 1982, 31441 Dammam, Saudi Arabia
| | - Danah Aljaafari
- grid.411975.f0000 0004 0607 035XDepartment of Neurology, King Fahd Hospital of the University, Alkhobar, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Iname Khoda
- grid.411975.f0000 0004 0607 035XDepartment of Neurology, King Fahd Hospital of the University, Alkhobar, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Ahmed K. Abdelfatah
- grid.411975.f0000 0004 0607 035XDepartment of Neurosurgery, King Fahd Hospital of the University, Alkhobar, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Abdullah A. Alsulaiman
- grid.411975.f0000 0004 0607 035XDepartment of Neurology, King Fahd Hospital of the University, Alkhobar, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Firas Alanazi
- grid.411975.f0000 0004 0607 035XDepartment of Neurosurgery, King Fahd Hospital of the University, Alkhobar, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Rawan Alanazi
- grid.411975.f0000 0004 0607 035XDepartment of Neurosurgery, King Fahd Hospital of the University, Alkhobar, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Divya Gandla
- grid.25879.310000 0004 1936 8972Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA USA
| | - Hetal Lad
- grid.25879.310000 0004 1936 8972Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA USA
| | - Samar Barayan
- grid.411975.f0000 0004 0607 035XDepartment of Neurosurgery, King Fahd Hospital of the University, Alkhobar, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Brendan J. Keating
- grid.25879.310000 0004 1936 8972Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA USA
| | - Amein K. Al-Ali
- grid.411975.f0000 0004 0607 035XDepartment of Clinical Biochemistry, College of Medicine, Imam Abdulrahman Bin Faisal University, P. O. Box 1982, 31441 Dammam, Saudi Arabia
| |
Collapse
|
3
|
Bellucco FT, de Mello CB, Meloni VA, Melaragno MI. Malan syndrome in a patient with 19p13.2p13.12 deletion encompassing NFIX and CACNA1A genes: Case report and review of the literature. Mol Genet Genomic Med 2019; 7:e997. [PMID: 31574590 PMCID: PMC6900369 DOI: 10.1002/mgg3.997] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 09/16/2019] [Indexed: 11/16/2022] Open
Abstract
Background Malan syndrome is a recently introduced overgrowth disorder described in a limited number of individuals. Haploinsufficiency and also point mutations of NFIX gene have been proposed as its leading causative mechanism, however, due to the limited number of cases and different deletion sizes, genotype/phenotype correlations are still limited. Methods Here, we report the first Brazilian case of Malan syndrome caused by a 990 kb deletion in 19p13.2p13.12, focusing on clinical and behavioral aspects of the syndrome. Results The patient presented with macrocephaly, facial dysmorphisms, hypotonia, developmental delay, moderate thoracolumbar scoliosis, and seizures. The intellectual and behavioral assessments showed severe cognitive, language, and adaptive functions impairments. The 19p deleted region of our patient encompasses NFIX, CACNA1A, which seems to be related to a higher frequency of seizures among individuals with microdeletions in 19p13.2, and 15 other coding genes, including CC2D1A and NACC1, both known to be involved in neurobiological process and pathways. Conclusion Deletions involving NFIX gene should be considered in patients with overgrowth during childhood, macrocephaly, developmental delay, and seizures, as well as severe intellectual disability.
Collapse
Affiliation(s)
- Fernanda T Bellucco
- Department of Morphology and Genetics, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Claudia B de Mello
- Department of Psychobiology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Vera A Meloni
- Department of Morphology and Genetics, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Maria Isabel Melaragno
- Department of Morphology and Genetics, Universidade Federal de São Paulo, São Paulo, Brazil
| |
Collapse
|
4
|
Culjat M, Razak J, Saadeh‐Haddad R, Driggers R, Kamholz K, Timofeev J. Perinatal findings in a patient with a novel large chromosome 19p deletion. Clin Case Rep 2018; 6:1525-1530. [PMID: 30147897 PMCID: PMC6099042 DOI: 10.1002/ccr3.1615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 03/16/2018] [Accepted: 05/08/2018] [Indexed: 12/02/2022] Open
Abstract
We describe the prenatal and postnatal course of an infant with a large 19p deletion. Cases such as ours will improve the knowledge of specific gene functions for every medical specialist. The goal is to allow for a more rapid diagnosis, accurate prognosis and to decrease the likelihood of complications.
Collapse
Affiliation(s)
- Marko Culjat
- MedStar Georgetown University HospitalNeonatal‐Perinatal MedicineWashingtonDCUSA
| | - Jennifer Razak
- Division of Maternal Fetal MedicineSibley Memorial HospitalWashingtonDCUSA
| | - Reem Saadeh‐Haddad
- Department of PediatricsMedStar Georgetown University HospitalWashingtonDCUSA
| | - Rita Driggers
- Division of Maternal Fetal MedicineSibley Memorial HospitalWashingtonDCUSA
- Division of Maternal Fetal MedicineJohns Hopkins School of MedicineBaltimoreMDUSA
| | - Karen Kamholz
- MedStar Georgetown University HospitalNeonatal‐Perinatal MedicineWashingtonDCUSA
| | - Julia Timofeev
- Division of Maternal Fetal MedicineSibley Memorial HospitalWashingtonDCUSA
- Division of Maternal Fetal MedicineJohns Hopkins School of MedicineBaltimoreMDUSA
| |
Collapse
|
5
|
Abstract
Craniosynostosis refers to a condition during early development in which one or more of the fibrous sutures of the skull prematurely fuse by turning into bone, which produces recognizable patterns of cranial shape malformations depending on which suture(s) are affected. In addition to cases with isolated cranial dysmorphologies, craniosynostosis appears in syndromes that include skeletal features of the eyes, nose, palate, hands, and feet as well as impairment of vision, hearing, and intellectual development. Approximately 85% of the cases are nonsyndromic sporadic and emerge after de novo structural genome rearrangements or single nucleotide variation, while the remainders consist of syndromic cases following mendelian inheritance. By karyotyping, genome wide linkage, and CNV analyses as well as by whole exome and whole genome sequencing, numerous candidate genes for craniosynostosis belonging to the FGF, Wnt, BMP, Ras/ERK, ephrin, hedgehog, STAT, and retinoic acid signaling pathways have been identified. Many of the craniosynostosis-related candidate genes form a functional network based upon protein-protein or protein-DNA interactions. Depending on which node of this craniosynostosis-related network is affected by a gene mutation or a change in gene expression pattern, a distinct craniosynostosis syndrome or set of phenotypes ensues. Structural variations may alter the dosage of one or several genes or disrupt the genomic architecture of genes and their regulatory elements within topologically associated chromatin domains. These may exert dominant effects by either haploinsufficiency, dominant negative partial loss of function, gain of function, epistatic interaction, or alteration of levels and patterns of gene expression during development. Molecular mechanisms of dominant modes of action of these mutations may include loss of one or several binding sites for cognate protein partners or transcription factor binding sequences. Such losses affect interactions within functional networks governing development and consequently result in phenotypes such as craniosynostosis. Many of the novel variants identified by genome wide CNV analyses, whole exome and whole genome sequencing are incorporated in recently developed diagnostic algorithms for craniosynostosis.
Collapse
Affiliation(s)
- Martin Poot
- Department of Human Genetics, University of Würzburg, Würzburg, Germany
| |
Collapse
|