1
|
Marafi D. Founder mutations and rare disease in the Arab world. Dis Model Mech 2024; 17:dmm050715. [PMID: 38922202 PMCID: PMC11225585 DOI: 10.1242/dmm.050715] [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] [Indexed: 06/27/2024] Open
Abstract
Founder mutations are disease-causing variants that occur frequently in geographically or culturally isolated groups whose shared ancestor(s) carried the pathogenic variant. While some disease alleles may vanish from the genetic pool due to natural selection, variants with weaker effects may survive for a long time, thereby enhancing the prevalence of some rare diseases. These are predominantly autosomal recessive diseases but can also be autosomal dominant traits with late-onset or mild phenotypes. Cultural practices, such as endogamy and consanguinity, in these isolated groups lead to higher prevalence of such rare diseases compared to the rest of the population and worldwide. In this Perspective, we define population isolates and the underlying genetic mechanisms for accumulating founder mutations. We also discuss the current and potential scientific, clinical and public-health implications of studying founder mutations in population isolates around the world, with a particular focus on the Arab population.
Collapse
Affiliation(s)
- Dana Marafi
- Department of Pediatrics, College of Medicine, Kuwait University, P.O. Box 24923, 13110 Safat, Kuwait
- Section of Child Neurology, Department of Pediatrics, Adan Hospital, Ministry of Health, Hadiya 52700, Kuwait
- Kuwait Medical Genetics Centre, Ministry of Health, Sulaibikhat 80901, Kuwait
| |
Collapse
|
2
|
Nerakh G, Vasikarla M. A novel pathogenic compound heterozygous variant in C12orf57 gene in a child with Temtamy syndrome presenting with overlapping phenotypic features of Kabuki-like syndrome. Brain Dev 2023; 45:512-516. [PMID: 37451886 DOI: 10.1016/j.braindev.2023.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 06/25/2023] [Accepted: 06/26/2023] [Indexed: 07/18/2023]
Abstract
BACKGROUND Autism spectrum disorder is a major neurodevelopmental disorder. Temtamy syndrome is a rare syndromic intellectual developmental disorder that presents with global developmental delay, autism, seizures, and agenesis/dysgenesis of the corpus callosum. METHODS We report a case of a male child who presented with global developmental delay, and autism. Additional clinical features in the child were prominent eyes, long palpebral fissures with eversion of lateral third of the lower eyelid, hypoplastic nipples, and persistent fetal fingertip pads. The clinical features were in favor of Kabuki-like syndrome. MRI brain revealed corpus callosal dysgenesis, mild cerebellar para-vermian, and vermian atrophy. RESULTS Trio exome sequencing has revealed a novel pathogenic compound heterozygous variant c.145A >T (p.Lys49Ter) and c.224_242del (p.Val85GlufsTer88) in exon 2 of the C12orf57 gene. CONCLUSION This is the first case of Temtamy syndrome reported from India with additional novel phenotypic features not reported previously and broadens the phenotypic spectrum of the disorder. In addition, it expands the spectrum of pathogenic variants in the C12orf57 gene.
Collapse
Affiliation(s)
- Gayatri Nerakh
- Department of Genetics, Fernandez Foundation, Hyderabad, India.
| | | |
Collapse
|
3
|
Sefrioui M, Ed-Darraz I, El Belidi H, Amazouzi A, Cherkaoui L. Manifestations oculaires au cours du syndrome de Temtamy : à propos d’un cas. J Fr Ophtalmol 2022; 45:e433-e435. [DOI: 10.1016/j.jfo.2022.05.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Revised: 04/27/2022] [Accepted: 05/05/2022] [Indexed: 10/16/2022]
|
5
|
Wang Y, Li M, Luo Y, Zhao X, Liao S, Jiang L, Li X, Zhong M. Temtamy syndrome caused by a new C12orf57 variant in a Chinese boy, including pedigree analysis and literature review. Exp Ther Med 2019; 19:327-332. [PMID: 31853307 DOI: 10.3892/etm.2019.8183] [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: 01/07/2019] [Accepted: 10/07/2019] [Indexed: 11/05/2022] Open
Abstract
Temtamy syndrome is an extremely rare disorder caused by chromosome 12 open reading frame 57 (C12orf57) pathogenic variants. The present study reported a boy with Temtamy syndrome displaying global developmental delay, epilepsy and dysmorphic facial appearance. Whole-exome sequencing was performed to identify a novel homozygous pathogenic variant of C12orf57 (c.3G >C, p.Met1IIe), and the affected protein structure and function were predicted to be pathogenic. Additionally, clinical features of the other reported 56 patients with C12orf57 pathogenic variants were reviewed and compared. This study highlighted that C12orf57 pathogenic variants are mainly associated with global developmental delay, epilepsy and dysmorphic facial appearances. The clinical features were in accordance with the previously reported cases, except for those with recurrent infection, but without corpus callosum abnormalities. The present study reported the first Asian case to the best of our knowledge with Temtamy syndrome, and the novel C12orf57 pathogenic variant has not reported in any ethnic groups previously. The present study expanded the spectrum of C12orf57 pathogenic variants as well as the ethnic backgrounds of the affected patients.
Collapse
Affiliation(s)
- Yanqin Wang
- Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing 400014, P.R. China.,Pediatric Research Institute, China International Science and Technology Cooperation Base of Child Development and Critical Disorders, National Clinical Research Center for Child Health and Disorders, Chongqing Engineering Research Center of Stem Cell Therapy, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing 400014, P.R. China
| | - Ming Li
- Department of Respiration, Kunming Children's Hospital, Kunming, Yunnan 650000, P.R. China
| | - Yuanyuan Luo
- Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing 400014, P.R. China.,Pediatric Research Institute, China International Science and Technology Cooperation Base of Child Development and Critical Disorders, National Clinical Research Center for Child Health and Disorders, Chongqing Engineering Research Center of Stem Cell Therapy, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing 400014, P.R. China
| | - Xin Zhao
- Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing 400014, P.R. China.,Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, Guangdong 518052, P.R. China
| | - Shuang Liao
- Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing 400014, P.R. China.,Pediatric Research Institute, China International Science and Technology Cooperation Base of Child Development and Critical Disorders, National Clinical Research Center for Child Health and Disorders, Chongqing Engineering Research Center of Stem Cell Therapy, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing 400014, P.R. China
| | - Li Jiang
- Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing 400014, P.R. China.,Pediatric Research Institute, China International Science and Technology Cooperation Base of Child Development and Critical Disorders, National Clinical Research Center for Child Health and Disorders, Chongqing Engineering Research Center of Stem Cell Therapy, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing 400014, P.R. China
| | - Xiujuan Li
- Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing 400014, P.R. China.,Pediatric Research Institute, China International Science and Technology Cooperation Base of Child Development and Critical Disorders, National Clinical Research Center for Child Health and Disorders, Chongqing Engineering Research Center of Stem Cell Therapy, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing 400014, P.R. China
| | - Min Zhong
- Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing 400014, P.R. China.,Pediatric Research Institute, China International Science and Technology Cooperation Base of Child Development and Critical Disorders, National Clinical Research Center for Child Health and Disorders, Chongqing Engineering Research Center of Stem Cell Therapy, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing 400014, P.R. China.,Department of Pediatrics, Qianjiang Central Hospital of Chongqing, Chongqing 409000, P.R. China
| |
Collapse
|
6
|
Reis LM, Sorokina EA, Thompson S, Muheisen S, Velinov M, Zamora C, Aylsworth AS, Semina EV. De Novo Missense Variants in WDR37 Cause a Severe Multisystemic Syndrome. Am J Hum Genet 2019; 105:425-433. [PMID: 31327510 PMCID: PMC6698968 DOI: 10.1016/j.ajhg.2019.06.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Accepted: 06/14/2019] [Indexed: 01/06/2023] Open
Abstract
While genetic causes are known for many syndromes involving developmental anomalies, a large number of individuals with overlapping phenotypes remain undiagnosed. Using exome-sequencing analysis and review of matchmaker databases, we have discovered four de novo missense variants predicted to affect the N-terminal region of WDR37-p.Ser119Phe, p.Thr125Ile, p.Ser129Cys, and p.Thr130Ile-in unrelated individuals with a previously unrecognized syndrome. Features of WDR37 syndrome include the following: ocular anomalies such as corneal opacity/Peters anomaly, coloboma, and microcornea; dysmorphic facial features; significant neurological impairment with structural brain defects and seizures; poor feeding; poor post-natal growth; variable skeletal, cardiac, and genitourinary defects; and death in infancy in one individual. WDR37 encodes a protein of unknown function with seven predicted WD40 domains and no previously reported human pathogenic variants. Immunocytochemistry and western blot studies showed that wild-type WDR37 is localized predominantly in the cytoplasm and mutant proteins demonstrate similar protein levels and localization. CRISPR-Cas9-mediated genome editing generated zebrafish mutants with novel missense and frameshift alleles: p.Ser129Phe, p.Ser129Cys (which replicates one of the human variants), p.Ser129Tyr, p.Lys127Cysfs, and p.Gln95Argfs. Zebrafish carrying heterozygous missense variants demonstrated poor growth and larval lethality, while heterozygotes with frameshift alleles survived to adulthood, suggesting a potential dominant-negative mechanism for the missense variants. RNA-seq analysis of zebrafish embryos carrying a missense variant detected significant upregulation of cholesterol biosynthesis pathways. This study identifies variants in WDR37 associated with human disease and provides insight into its essential role in vertebrate development and possible molecular functions.
Collapse
Affiliation(s)
- Linda M Reis
- Department of Pediatrics, Children's Research Institute, Medical College of Wisconsin and Children's Hospital of Wisconsin, Milwaukee, WI 53226, USA
| | - Elena A Sorokina
- Department of Pediatrics, Children's Research Institute, Medical College of Wisconsin and Children's Hospital of Wisconsin, Milwaukee, WI 53226, USA
| | - Samuel Thompson
- Department of Pediatrics, Children's Research Institute, Medical College of Wisconsin and Children's Hospital of Wisconsin, Milwaukee, WI 53226, USA
| | - Sanaa Muheisen
- Department of Pediatrics, Children's Research Institute, Medical College of Wisconsin and Children's Hospital of Wisconsin, Milwaukee, WI 53226, USA
| | - Milen Velinov
- Department of Human Genetics, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314, USA
| | - Carlos Zamora
- Department of Radiology, Division of Neuroradiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Arthur S Aylsworth
- Departments of Pediatrics and Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Elena V Semina
- Department of Pediatrics, Children's Research Institute, Medical College of Wisconsin and Children's Hospital of Wisconsin, Milwaukee, WI 53226, USA; Departments of Ophthalmology and Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| |
Collapse
|
7
|
Genetics of anophthalmia and microphthalmia. Part 1: Non-syndromic anophthalmia/microphthalmia. Hum Genet 2019; 138:799-830. [PMID: 30762128 DOI: 10.1007/s00439-019-01977-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 01/30/2019] [Indexed: 12/22/2022]
Abstract
Eye formation is the result of coordinated induction and differentiation processes during embryogenesis. Disruption of any one of these events has the potential to cause ocular growth and structural defects, such as anophthalmia and microphthalmia (A/M). A/M can be isolated or occur with systemic anomalies, when they may form part of a recognizable syndrome. Their etiology includes genetic and environmental factors; several hundred genes involved in ocular development have been identified in humans or animal models. In humans, around 30 genes have been repeatedly implicated in A/M families, although many other genes have been described in single cases or families, and some genetic syndromes include eye anomalies occasionally as part of a wider phenotype. As a result of this broad genetic heterogeneity, with one or two notable exceptions, each gene explains only a small percentage of cases. Given the overlapping phenotypes, these genes can be most efficiently tested on panels or by whole exome/genome sequencing for the purposes of molecular diagnosis. However, despite whole exome/genome testing more than half of patients currently remain without a molecular diagnosis. The proportion of undiagnosed cases is even higher in those individuals with unilateral or milder phenotypes. Furthermore, even when a strong gene candidate is available for a patient, issues of incomplete penetrance and germinal mosaicism make diagnosis and genetic counseling challenging. In this review, we present the main genes implicated in non-syndromic human A/M phenotypes and, for practical purposes, classify them according to the most frequent or predominant phenotype each is associated with. Our intention is that this will allow clinicians to rank and prioritize their molecular analyses and interpretations according to the phenotypes of their patients.
Collapse
|