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Carter MT, Srour M, Au PYB, Buhas D, Dyack S, Eaton A, Inbar-Feigenberg M, Howley H, Kawamura A, Lewis SME, McCready E, Nelson TN, Vallance H. Genetic and metabolic investigations for neurodevelopmental disorders: position statement of the Canadian College of Medical Geneticists (CCMG). J Med Genet 2023; 60:523-532. [PMID: 36822643 DOI: 10.1136/jmg-2022-108962] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 01/27/2023] [Indexed: 02/25/2023]
Abstract
PURPOSE AND SCOPE The aim of this position statement is to provide recommendations for clinicians regarding the use of genetic and metabolic investigations for patients with neurodevelopmental disorders (NDDs), specifically, patients with global developmental delay (GDD), intellectual disability (ID) and/or autism spectrum disorder (ASD). This document also provides guidance for primary care and non-genetics specialists caring for these patients while awaiting consultation with a clinical geneticist or metabolic specialist. METHODS OF STATEMENT DEVELOPMENT A multidisciplinary group reviewed existing literature and guidelines on the use of genetic and metabolic investigations for the diagnosis of NDDs and synthesised the evidence to make recommendations relevant to the Canadian context. The statement was circulated for comment to the Canadian College of Medical Geneticists (CCMG) membership-at-large and to the Canadian Pediatric Society (Mental Health and Developmental Disabilities Committee); following incorporation of feedback, it was approved by the CCMG Board of Directors on 1 September 2022. RESULTS AND CONCLUSIONS Chromosomal microarray is recommended as a first-tier test for patients with GDD, ID or ASD. Fragile X testing should also be done as a first-tier test when there are suggestive clinical features or family history. Metabolic investigations should be done if there are clinical features suggestive of an inherited metabolic disease, while the patient awaits consultation with a metabolic physician. Exome sequencing or a comprehensive gene panel is recommended as a second-tier test for patients with GDD or ID. Genetic testing is not recommended for patients with NDDs in the absence of GDD, ID or ASD, unless accompanied by clinical features suggestive of a syndromic aetiology or inherited metabolic disease.
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Affiliation(s)
| | - Myriam Srour
- Division of Neurology, McGill University Health Centre, Montreal, Québec, Canada
- Department of Pediatrics, McGill University, Montréal, QC, Canada
| | - Ping-Yee Billie Au
- Department of Medical Genetics, Alberta Children's Hospital, Calgary, Alberta, Canada
| | - Daniela Buhas
- Division of Medical Genetics, Department of Specialized Medicine, McGill University Health Centre, McGill University, Montreal, Québec, Canada
- Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Sarah Dyack
- Division of Medical Genetics, IWK Health Centre, Halifax, Nova Scotia, Canada
- Department of Pediatrics, Dalhousie University, Halifax, NS, Canada
| | - Alison Eaton
- Department of Medical Genetics, Stollery Children's Hospital, Edmonton, Alberta, Canada
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
| | - Michal Inbar-Feigenberg
- Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Heather Howley
- Office of Research Services, CHEO Research Institute, Ottawa, Ontario, Canada
| | - Anne Kawamura
- Division of Developmental Pediatrics, Holland Bloorview Kids Rehabilitation Hospital, Toronto, Ontario, Canada
- Department of Paediatrics, University of Toronto, Toronto, ON, Canada
- Mental Health and Developmental Disability Committee, Canadian Pediatric Society, Ottawa, ON, Canada
- Canadian Paediatric Society, Toronto, Ontario, Canada
| | - Suzanne M E Lewis
- Department of Medical Genetics, BC Children's and Women's Hospital, Vancouver, British Columbia, Canada
| | - Elizabeth McCready
- Department of Pathology and Molecular Medicine, McMaster University, McMaster University, Hamilton, ON, Canada, Hamilton, Ontario, Canada
- Hamilton Regional Laboratory Medicine Program, Hamilton Health Sciences Centre, Hamilton, ON, Canada
| | - Tanya N Nelson
- Department of Pathology and Laboratory Medicine, BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Hilary Vallance
- Department of Pathology and Laboratory Medicine, BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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Mei L, Hu C, Li D, Wang Y, Li H, Zhang K, Zhou B, Zhu R, Hagerman RJ, Xu X, Xu Q. The incidence and clinical characteristics of fragile X syndrome in China. Front Pediatr 2023; 11:1064104. [PMID: 36861076 PMCID: PMC9969088 DOI: 10.3389/fped.2023.1064104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 01/02/2023] [Indexed: 02/16/2023] Open
Abstract
Introduction Fragile X syndrome (FXS) is a X-linked neurodevelopmental disorder (NDD). This study aims to investigate the incidence of FXS in Chinese children and analyze the comprehensive clinical characteristics of these FXS children. Methods Children diagnosed with idiopathic NDD were recruited between 2016 and 2021 from the department of Child Health Care, Children's Hospital of Fudan University. We combined tetraplet-primed PCR-capillary electrophoresis and whole exome sequencing (WES)/panel or array-based comparative genomic hybridization (array-CGH) to identify the size of the CGG repeats and the mutations or copy number variations (CNVs) in the genome and in FMR1. The clinical features of FXS children were analyzed according to pediatricians' recording, parental questionnaires, the results of examinations and follow-up. Results The incidence of FXS in Chinese children with idiopathic NDD was 2.4% (42/1753) and in those with FXS, 2.38% had a deletion (1/42). Here, we present the clinical characteristics of 36 children with FXS. Overweight was observed in two boys. The average intelligence quotient (IQ)/development quotient (DQ) of all FXS patients was 48. The average ages of meaningful words and walking alone were 2 years and 10 months and 1 year and 7 months, respectively. The most frequent repetitive behavior was stimulated by hyperarousal to sensory stimulation. On social aspects, social withdrawal, social anxiety, and shyness accounted for 75%, 58%, and 56% of the total number of children, respectively. Approximately 60% of FXS children in this cohort were emotionally labile and prone to temper tantrums. Self-injury and aggression toward others could also be observed, at 19% and 28%, respectively. The most frequent behavioral problem was attention-deficit hyperactivity disorder (ADHD) seen in 64% and the most common facial features were a narrow and elongated face and large or prominent ears in 92% of patients. Discussion Screening of FMR1 full mutation provides the possibility for patients' further medical supports and the clinical features of FXS children obtained in this study will increase the understanding and diagnosis of FXS.
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Affiliation(s)
- Lianni Mei
- Department of Child Health Care, Children's Hospital of Fudan University, Shanghai, China
| | - Chunchun Hu
- Department of Child Health Care, Children's Hospital of Fudan University, Shanghai, China
| | - Dongyun Li
- Department of Child Health Care, Children's Hospital of Fudan University, Shanghai, China
| | - Ya Wang
- Department of Child Health Care, Anhui Provincial Children's Hospital, Hefei, China
| | - Huiping Li
- Department of Child Health Care, Children's Hospital of Fudan University, Shanghai, China
| | - Kaifeng Zhang
- Department of Child Health Care, Children's Hospital of Fudan University, Shanghai, China
| | - Bingrui Zhou
- Department of Child Health Care, Children's Hospital of Fudan University, Shanghai, China
| | - Ruoping Zhu
- Department of Child Health Care, Anhui Provincial Children's Hospital, Hefei, China
| | - Randi J. Hagerman
- The MIND Institute, University of California Davis Medical Center, Sacramento, CA, United States
- Department of Pediatrics, University of California Davis Medical Center, Sacramento, CA, United States
| | - Xiu Xu
- Department of Child Health Care, Children's Hospital of Fudan University, Shanghai, China
| | - Qiong Xu
- Department of Child Health Care, Children's Hospital of Fudan University, Shanghai, China
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Zhang W, Li D, Pang N, Jiang L, Li B, Ye F, He F, Chen S, Liu F, Peng J, Yin J, Yin F. The second-tier status of fragile X syndrome testing for unexplained intellectual disability/global developmental delay in the era of next-generation sequencing. Front Pediatr 2022; 10:911805. [PMID: 35935362 PMCID: PMC9353215 DOI: 10.3389/fped.2022.911805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 06/28/2022] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE Although many unexplained intellectual disability/global developmental delay (ID/GDD) individuals have benefited from the excellent detection yield of copy number variations and next-generation sequencing testing, many individuals still who suffer from ID/GDD of unexplained etiology. In this study, we investigated the applicability of fragile X syndrome (FXS) testing in unexplained ID/GDD individuals with negative or absent genetic testing. METHODS In this study, we used the triplet repeat primed polymerase chain reaction to evaluate the value and application of fragile X testing in unexplained ID/GDD individuals with negative or absent genetic testing (n = 681) from three hospitals. RESULTS Of the 681 ID/GDD individuals with negative or absent genetic testing results detected by FXS testing, 12 men and one woman were positive. This corresponded to a diagnostic yield of 1.9% for FXS testing in our cohort. All FXS individuals had either a family history of ID/GDD or suggestive clinical features. The detection yield of FXS testing in ID/GDD individuals who completed genetic testing (2.70%, 12/438) was significantly higher than in individuals without any genetic testing (0.40%, 1/243). CONCLUSIONS This is the first report of FXS testing in ID/GDD individuals who lacked previous genetic testing, which promotes standardization of the FXS diagnostic process. These results highlight the utility of FXS testing of unexplained ID/GDD individuals with negative results from standard genetic testing. In the era of next-generation sequencing, FXS testing is more suitable as a second-tier choice and provides clinicians and geneticists with auxiliary references for tracing the etiology of ID/GDD.
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Affiliation(s)
- Wen Zhang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Pediatrics, Changsha, China.,Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Dong Li
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Pediatrics, Changsha, China.,Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Nan Pang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Pediatrics, Changsha, China.,Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Li Jiang
- Department of Neurology, Children's Hospital Affiliated to Chongqing Medical University, Chongqing, China
| | - Baomin Li
- Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, China
| | - Fanghua Ye
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Fang He
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Pediatrics, Changsha, China.,Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Shimeng Chen
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Pediatrics, Changsha, China.,Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Fangyun Liu
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Pediatrics, Changsha, China.,Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Jing Peng
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Pediatrics, Changsha, China.,Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Jinghua Yin
- Department of Pathophysiology, Xiangya Hospital, Central South University, Changsha, China
| | - Fei Yin
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Pediatrics, Changsha, China.,Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
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FMR1 allele frequencies in 51,000 newborns: a large-scale population study in China. World J Pediatr 2021; 17:653-658. [PMID: 34738199 DOI: 10.1007/s12519-021-00473-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 10/05/2021] [Indexed: 10/19/2022]
Abstract
BACKGROUND Fragile X syndrome (FXS), caused by CGG-repeat expansion in FMR1 promoter, is one of the most common causes of mental retardation. Individuals with full mutation and premutation alleles have a high risk of psychophysiological disorder and of having affected offspring. Frequencies of FMR1 alleles in general newborns have been reported in Caucasians but have not been investigated in the large-scale population in the mainland of China. METHODS The sizes of FMR1 CGG-repeats were analyzed in 51,661 newborns (28,114 males and 23,547 females) and also in a cohort of 33 children diagnosed with developmental delay using GC-rich polymerase chain reaction (PCR) and triple repeat primed PCR. RESULTS The frequency of CGG repeats > 100 was 1/9371 in males and 1/5887 in females, and the frequency of CGG repeats > 54 was 1/1561 in males and 1/1624 in females. FMR1 full mutation and premutation were identified in 27.27% of children who had Ages and Stages Questionnaire scores less than two standard deviations from the cutoff value. CONCLUSIONS Our study revealed the prevalence of FXS in China and improved the sample databases of FXS, suggesting that the prevalence of FXS in Chinese is higher than estimated previously and that FXS screening can be advised to high-risk families.
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Lin L, Zhang Y, Pan H, Wang J, Qi Y, Ma Y. Clinical and genetic characteristics and prenatal diagnosis of patients presented GDD/ID with rare monogenic causes. Orphanet J Rare Dis 2020; 15:317. [PMID: 33176815 PMCID: PMC7656751 DOI: 10.1186/s13023-020-01599-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 10/26/2020] [Indexed: 12/18/2022] Open
Abstract
Background Global developmental delay/intellectual disability (GDD/ID), used to be named as mental retardation (MR), is one of the most common phenotypes in neurogenetic diseases. In this study, we described the diagnostic courses, clinical and genetic characteristics and prenatal diagnosis of a cohort with patients presented GDD/ID with monogenic causes, from the perspective of a tertiary genetic counseling and prenatal diagnostic center. Method We retrospectively analyzed the diagnostic courses, clinical characteristics, and genetic spectrum of patients presented GDD/ID with rare monogenic causes. We also conducted a follow-up study on prenatal diagnosis in these families. Pathogenicity of variants was interpreted by molecular geneticists and clinicians according to the guidelines of the American College of Medical Genetics and Genomics (ACMG). Results Among 81 patients with GDD/ID caused by rare monogenic variants it often took 0.5–4.5 years and 2–8 referrals to obtain genetic diagnoses. Devlopmental delay typically occurred before 3 years of age, and patients usually presented severe to profound GDD/ID. The most common co-existing conditions were epilepsy (58%), microcephaly (21%) and facial anomalies (17%). In total, 111 pathogenic variants were found in 62 different genes among the 81 pedigrees, and 56 variants were novel. The most common inheritance patterns in this outbred Chinese population were autosomal dominant (AD; 47%), following autosomal recessive (AR; 37%), and X-linked (XL; 16%). SCN2A, SHANK3 and STXBP1 were important causal genes. Hot-spot variants were rarely found. By the follow-up, 33 affected families, including 15, 13 and 5 families inherited in AR, AD and XL modes respectively, had undergone prenatal diagnosis. And the recurrence rates are 26.7%, 15.4% and 20% for families inherited in AR, AD, and XL patterns. Conclusion Patients presented with GDD/ID caused by rare single gene variants are characterized by early onset, relatively severe symptoms and great clinical variability and genetic heterogeneity. Timely referrals to genetic counseling and prenatal diagnostic laboratories are important for affected families planning to have additional children.
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Affiliation(s)
- Liling Lin
- Department of Central Laboratory, Peking University First Hospital, No. 8, Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Ying Zhang
- Department of Central Laboratory, Peking University First Hospital, No. 8, Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Hong Pan
- Department of Central Laboratory, Peking University First Hospital, No. 8, Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Jingmin Wang
- Department of Pediatrics, Peking University First Hospital, No. 8, Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Yu Qi
- Department of Central Laboratory, Peking University First Hospital, No. 8, Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Yinan Ma
- Department of Central Laboratory, Peking University First Hospital, No. 8, Xishiku Street, Xicheng District, Beijing, 100034, China.
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Urine-Derived Epithelial Cell Lines: A New Tool to Model Fragile X Syndrome (FXS). Cells 2020; 9:cells9102240. [PMID: 33027907 PMCID: PMC7600987 DOI: 10.3390/cells9102240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/29/2020] [Accepted: 10/02/2020] [Indexed: 02/08/2023] Open
Abstract
Fragile X syndrome (FXS) is an X-linked neurodevelopmental condition associated with intellectual disability and behavioral problems due to the lack of the Fragile X mental retardation protein (FMRP), which plays a crucial role in synaptic plasticity and memory. A desirable in vitro cell model to study FXS would be one that can be generated by simple isolation and culture method from a collection of a non-invasive donor specimen. Currently, the various donor-specific cells can be isolated mainly from peripheral blood and skin biopsy. However, they are somewhat invasive methods for establishing cell lines from the primary subject material. In this study, we characterized a cost-effective and straightforward method to derive epithelial cell lines from urine samples collected from participants with FXS and healthy controls (TD). The urine-derived cells expressed epithelial cell surface markers via fluorescence-activated cell sorting (FACS). We observed inter, and the intra-tissue CGG mosaicism in the PBMCs and the urine-derived cells from participants with FXS potentially related to the observed variations in the phenotypic and clinical presentation FXS. We characterized these urine-derived epithelial cells for FMR1 mRNA and FMRP expression and observed some expression in the lines derived from full mutation mosaic participants. Further, FMRP expression was localized in the cytoplasm of the urine-derived epithelial cells of healthy controls. Deficient FMRP expression was also observed in mosaic males, while, as expected, no expression was observed in cells derived from participants with a hypermethylated full mutation.
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Xu Y, Sun S, Li N, Yu T, Wang X, Wang J, Bao N. Identification and analysis of the genetic causes in nine unrelated probands with syndromic craniosynostosis. Gene 2017; 641:144-150. [PMID: 29037998 DOI: 10.1016/j.gene.2017.10.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 09/29/2017] [Accepted: 10/12/2017] [Indexed: 12/31/2022]
Abstract
Syndromic craniosynostosis is a group of multiple conditions with high heterogeneity, and many rare syndromes still remain to be characterized. To identify and analyze causative genetic variants in nine unrelated probands mainly manifested as syndromic craniosynostosis, we reviewed the relevant medical information of the patients and performed the whole exome sequencing, further verified with Sanger sequencing and parental background. Bioinformatics analysis was used to evaluate the potential deleterious or benign effect of each genetic variant through evolutionary conservation alignment, multi-lines of computer predication and the allele frequency in population dataset (control and patient). The Standards and guidelines from American College of Medical Genetics and Genomics was used to classify and interpret the pathogenicity for each genetic variant. All the nine probands were found to carry the possibly causative variants, among which three variants including two missense mutations (c.3385C>T in IFT122 gene, c.3581A>G in SMC1A gene) and a frameshift mutation (c.434dupA in TWIST1 gene) have never been reported in patients before. We suggested Cornelia de Lange syndrome caused by SMC1A variant is a neglected syndromic craniosynostosis. Our study not only expanded genotypic and phenotypic spectrum of the rare syndromes, but also confirmed that there existed an underlying genetic mechanism. We emphasized that deliberate selection of both the potential candidates and comprehensive detection methods for genetic analysis is important to increase the genetic diagnosis yield of syndromic craninosynostosis.
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Affiliation(s)
- Yufei Xu
- Department of Medical Genetics and Molecular Diagnostic Laboratory, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China; Institute of Pediatric Translational Medicine, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Shouqing Sun
- Department of Neurosurgery, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Niu Li
- Department of Medical Genetics and Molecular Diagnostic Laboratory, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China; Institute of Pediatric Translational Medicine, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Tingting Yu
- Department of Medical Genetics and Molecular Diagnostic Laboratory, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China; Institute of Pediatric Translational Medicine, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Xiumin Wang
- Department of Endocrinology and Metabolism, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Jian Wang
- Department of Medical Genetics and Molecular Diagnostic Laboratory, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China; Institute of Pediatric Translational Medicine, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China.
| | - Nan Bao
- Department of Neurosurgery, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China.
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Niu M, Han Y, Dy ABC, Du J, Jin H, Qin J, Zhang J, Li Q, Hagerman RJ. Fragile X Syndrome: Prevalence, Treatment, and Prevention in China. Front Neurol 2017. [PMID: 28634468 PMCID: PMC5459883 DOI: 10.3389/fneur.2017.00254] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability and the leading monogenic cause of autism spectrum disorder. Although FXS has been studied for several decades, there is relatively little basic science or clinical research being performed on FXS in China. Indeed, there is a large gap between China and Western countries in the FXS field. China has a potentially large number of FXS patients. However, many of them are underdiagnosed or even misdiagnosed, and treatments are not always administered in the Chinese population. This review discusses the prevalence, treatment, and prevention of FXS in China to facilitate an understanding of this disease in the Chinese population.
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Affiliation(s)
- Manman Niu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Ying Han
- Department of Pediatrics, Peking University First Hospital, Beijing, China.,MIND Institute, University of California-Davis Medical Center, Sacramento, CA, United States
| | - Angel Belle C Dy
- MIND Institute, University of California-Davis Medical Center, Sacramento, CA, United States.,Ateneo de Manila University - School of Medicine and Public Health, Quezon, Philippines
| | - Junbao Du
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Hongfang Jin
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jiong Qin
- Department of Pediatrics, Peking University People's Hospital, Beijing, China
| | - Jing Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Qinrui Li
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Randi J Hagerman
- MIND Institute, University of California-Davis Medical Center, Sacramento, CA, United States.,Department of Pediatrics, University of California-Davis Medical Center, Sacramento, CA, United States
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Specchia V, D'Attis S, Puricella A, Bozzetti MP. dFmr1 Plays Roles in Small RNA Pathways of Drosophila melanogaster. Int J Mol Sci 2017; 18:ijms18051066. [PMID: 28509881 PMCID: PMC5454977 DOI: 10.3390/ijms18051066] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 05/09/2017] [Accepted: 05/10/2017] [Indexed: 11/16/2022] Open
Abstract
Fragile-X syndrome is the most common form of inherited mental retardation accompanied by other phenotypes, including macroorchidism. The disorder originates with mutations in the Fmr1 gene coding for the FMRP protein, which, with its paralogs FXR1 and FXR2, constitute a well-conserved family of RNA-binding proteins. Drosophila melanogaster is a good model for the syndrome because it has a unique fragile X-related gene: dFmr1. Recently, in addition to its confirmed role in the miRNA pathway, a function for dFmr1 in the piRNA pathway, operating in Drosophila gonads, has been established. In this review we report a summary of the piRNA pathways occurring in gonads with a special emphasis on the relationship between the piRNA genes and the crystal-Stellate system; we also analyze the roles of dFmr1 in the Drosophila gonads, exploring their genetic and biochemical interactions to reveal some unexpected connections.
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Affiliation(s)
- Valeria Specchia
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali (DiSTeBA)-University of Salento, 73100 Lecce, Italy.
| | - Simona D'Attis
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali (DiSTeBA)-University of Salento, 73100 Lecce, Italy.
| | - Antonietta Puricella
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali (DiSTeBA)-University of Salento, 73100 Lecce, Italy.
| | - Maria Pia Bozzetti
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali (DiSTeBA)-University of Salento, 73100 Lecce, Italy.
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