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Elhawary NA, AlJahdali IA, Abumansour IS, Azher ZA, Falemban AH, Madani WM, Alosaimi W, Alghamdi G, Sindi IA. Phenotypic variability to medication management: an update on fragile X syndrome. Hum Genomics 2023; 17:60. [PMID: 37420260 DOI: 10.1186/s40246-023-00507-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 07/03/2023] [Indexed: 07/09/2023] Open
Abstract
This review discusses the discovery, epidemiology, pathophysiology, genetic etiology, molecular diagnosis, and medication-based management of fragile X syndrome (FXS). It also highlights the syndrome's variable expressivity and common comorbid and overlapping conditions. FXS is an X-linked dominant disorder associated with a wide spectrum of clinical features, including but not limited to intellectual disability, autism spectrum disorder, language deficits, macroorchidism, seizures, and anxiety. Its prevalence in the general population is approximately 1 in 5000-7000 men and 1 in 4000-6000 women worldwide. FXS is associated with the fragile X messenger ribonucleoprotein 1 (FMR1) gene located at locus Xq27.3 and encodes the fragile X messenger ribonucleoprotein (FMRP). Most individuals with FXS have an FMR1 allele with > 200 CGG repeats (full mutation) and hypermethylation of the CpG island proximal to the repeats, which silences the gene's promoter. Some individuals have mosaicism in the size of the CGG repeats or in hypermethylation of the CpG island, both produce some FMRP and give rise to milder cognitive and behavioral deficits than in non-mosaic individuals with FXS. As in several monogenic disorders, modifier genes influence the penetrance of FMR1 mutations and FXS's variable expressivity by regulating the pathophysiological mechanisms related to the syndrome's behavioral features. Although there is no cure for FXS, prenatal molecular diagnostic testing is recommended to facilitate early diagnosis. Pharmacologic agents can reduce some behavioral features of FXS, and researchers are investigating whether gene editing can be used to demethylate the FMR1 promoter region to improve patient outcomes. Moreover, clustered regularly interspaced palindromic repeats (CRISPR)/Cas9 and developed nuclease defective Cas9 (dCas9) strategies have promised options of genome editing in gain-of-function mutations to rewrite new genetic information into a specified DNA site, are also being studied.
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Affiliation(s)
- Nasser A Elhawary
- Department of Medical Genetics, College of Medicine, Umm Al-Qura University, Mecca, 21955, Saudi Arabia.
| | - Imad A AlJahdali
- Department of Community Medicine, College of Medicine, Umm Al-Qura University, Mecca, Saudi Arabia
| | - Iman S Abumansour
- Department of Medical Genetics, College of Medicine, Umm Al-Qura University, Mecca, 21955, Saudi Arabia
| | - Zohor A Azher
- Department of Medical Genetics, College of Medicine, Umm Al-Qura University, Mecca, 21955, Saudi Arabia
| | - Alaa H Falemban
- Department of Pharmacology and Toxicology, College of Medicine, Umm Al-Qura University, Mecca, 24382, Saudi Arabia
| | - Wefaq M Madani
- Department of Hematology and Immunology, Faculty of Medicine, Umm Al-Qura University, Mecca, Saudi Arabia
| | - Wafaa Alosaimi
- Department of Hematology, Maternity and Children Hospital, Mecca, Saudi Arabia
| | - Ghydda Alghamdi
- Department of Medical Genetics, College of Medicine, Umm Al-Qura University, Mecca, 21955, Saudi Arabia
| | - Ikhlas A Sindi
- Department of Biology, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
- Preparatory Year Program, Batterjee Medical College, Jeddah, 21442, Saudi Arabia
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Shahid R, Yasin M, Rehman ZU, Jadoon H, Tahir H, Meraj N, Khan N, Zubair M, Zulfiqar I, Nowshid M, Azeem A, Jabeen M, Hameed A, Saleha S. Maternal FMR1 alleles expansion in newborns during transmission: a prospective cohort study. Pediatr Res 2023; 93:720-724. [PMID: 35681093 DOI: 10.1038/s41390-022-02128-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 04/05/2022] [Accepted: 05/17/2022] [Indexed: 11/09/2022]
Abstract
INTRODUCTION The CGG repeats in the 5' untranslated region of the fragile X mental retardation 1 gene (FMR1) gene shows increased instability upon maternal transmission. Maternal FMR1 intermediate (45-54 repeats) and premutation (PM: 55-<200 repeats) alleles usually expand to full mutation (>200 repeats) alleles in offspring and consequently, cause fragile X syndrome (FXS) in them. METHODS In a prospective cohort study, Pakistani pregnant women in prenatal care were first screened for FMR1 expanded alleles. In the follow-up, pregnancy outcomes in women carrying FMR1 expanded alleles were recorded and their newborn offspring were also screened for FXS. RESULTS In a total of 1950 pregnant women, 89 (4.6%) were detected carriers for FMR1 expanded alleles; however, rates of detection of expanded alleles were found significantly high in women with a history of FXS. In addition, miscarriages and birth of affected newborns with FXS were significantly more common in women carrying large size PM alleles and had a history of FXS (P = 0.0494 and P = 0.0494, respectively). CONCLUSIONS The current study provides the first evidence of screening Pakistani pregnant women for FMR1 expanded alleles in prenatal care. Moreover, the miscarriage was also detected as a clinical predictor for FXS. IMPACT Offspring would have a higher risk of developing FXS due to maternal FMR1 alleles expansions during transmission. This is the first prospective cohort study in Pakistan for finding FMR1 allelic status of pregnant women and their newborn offspring in follow-up. The robust offspring risk for FXS estimated in this study may be valuable information for genetic counseling of women carriers for FMR1 expanded alleles. The family history and miscarriage were detected as effective indicators for FXS carrier screening in Pakistani women.
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Affiliation(s)
- Rabia Shahid
- Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology (KUST), Kohat, 26000, Khyber Pakhtunkhwa, Pakistan
| | - Muhammad Yasin
- Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology (KUST), Kohat, 26000, Khyber Pakhtunkhwa, Pakistan
| | - Zia Ur Rehman
- Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology (KUST), Kohat, 26000, Khyber Pakhtunkhwa, Pakistan
| | - Humaira Jadoon
- Department of Obstetrics & Gynecology, Ayub Medical Institute, Abbottabad, 22010, Khyber Pakhtunkhwa, Pakistan
| | - Haleema Tahir
- Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology (KUST), Kohat, 26000, Khyber Pakhtunkhwa, Pakistan
| | - Neelam Meraj
- Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology (KUST), Kohat, 26000, Khyber Pakhtunkhwa, Pakistan
| | - Niamat Khan
- Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology (KUST), Kohat, 26000, Khyber Pakhtunkhwa, Pakistan
| | - Maria Zubair
- Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology (KUST), Kohat, 26000, Khyber Pakhtunkhwa, Pakistan
| | - Irba Zulfiqar
- Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology (KUST), Kohat, 26000, Khyber Pakhtunkhwa, Pakistan
| | - Maha Nowshid
- Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology (KUST), Kohat, 26000, Khyber Pakhtunkhwa, Pakistan
| | - Arfa Azeem
- Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology (KUST), Kohat, 26000, Khyber Pakhtunkhwa, Pakistan
| | - Musarrat Jabeen
- Department of Obstetrics and Gynecology, Liaqat Memorial Hospital, KIMS, Kohat, 26000, Khyber Pakhtunkhwa, Pakistan
| | - Abdul Hameed
- Institute of Biomedical and Genetic Engineering (IBGE), Islamabad, 44000, Pakistan
| | - Shamim Saleha
- Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology (KUST), Kohat, 26000, Khyber Pakhtunkhwa, Pakistan.
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Beyond Trinucleotide Repeat Expansion in Fragile X Syndrome: Rare Coding and Noncoding Variants in FMR1 and Associated Phenotypes. Genes (Basel) 2021; 12:genes12111669. [PMID: 34828275 PMCID: PMC8623550 DOI: 10.3390/genes12111669] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/20/2021] [Accepted: 10/21/2021] [Indexed: 11/17/2022] Open
Abstract
FMR1 (FMRP translational regulator 1) variants other than repeat expansion are known to cause disease phenotypes but can be overlooked if they are not accounted for in genetic testing strategies. We collected and reanalyzed the evidence for pathogenicity of FMR1 coding, noncoding, and copy number variants published to date. There is a spectrum of disease-causing FMR1 variation, with clinical and functional evidence supporting pathogenicity of five splicing, five missense, one in-frame deletion, one nonsense, and four frameshift variants. In addition, FMR1 deletions occur in both mosaic full mutation patients and as constitutional pathogenic alleles. De novo deletions arise not only from full mutation alleles but also alleles with normal-sized CGG repeats in several patients, suggesting that the CGG repeat region may be prone to genomic instability even in the absence of repeat expansion. We conclude that clinical tests for potentially FMR1-related indications such as intellectual disability should include methods capable of detecting small coding, noncoding, and copy number variants.
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Villate O, Ibarluzea N, Maortua H, de la Hoz AB, Rodriguez-Revenga L, Izquierdo-Álvarez S, Tejada MI. Effect of AGG Interruptions on FMR1 Maternal Transmissions. Front Mol Biosci 2020; 7:135. [PMID: 32766278 PMCID: PMC7381193 DOI: 10.3389/fmolb.2020.00135] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 06/05/2020] [Indexed: 12/30/2022] Open
Abstract
There are four classes of CGG repeat alleles in the FMR1 gene: normal alleles have up to 44 repeats; patients with Fragile X Syndrome have more than 200 repeats; those between 55 and 200 CGGs are considered FMR1 premutation alleles, because they are associated with maternal expansions of the number of CGGs in the next generation and finally, alleles between 45 and 54 CGGs are called intermediate or gray zone alleles. In these last categories, the stability depends on the presence of AGG interruptions, which usually occurs between 9 and 10 CGGs. In this context, we have studied retrospectively 66 women with CGG repeats between 45 and 65, and their offspring. In total 87 transmissions were analyzed with triplet repeat primed PCR using AmplideX® FMR1 PCR (Asuragen, Austin, TX, USA) and we found that alleles with CGG repeats between 45 and 58 do not expand in the next generation except two cases with 56 repeats and 0 AGG interruptions. Furthermore, we have found four females with alleles with more than 59 CGG repeats and 2 AGG interruptions that do not expand either. Alleles from 56 CGG repeats without AGGs expand in all cases. In light of these results and those of the literature, we consider that the risk of unstable transmissions should be based on the presence or absence of AGG interruptions and not on the classical cutoffs which define each category of FMR1 alleles. The application of these results in the genetic and reproductive counseling is essential and AGG interruptions should always be studied.
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Affiliation(s)
- Olatz Villate
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain.,Genetics Service, Cruces University Hospital, Osakidetza Basque Health Service, Barakaldo, Spain.,Centre for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Nekane Ibarluzea
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain.,Centre for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Hiart Maortua
- Genetics Service, Cruces University Hospital, Osakidetza Basque Health Service, Barakaldo, Spain.,Centre for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Ana Belén de la Hoz
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain.,Centre for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Laia Rodriguez-Revenga
- Centre for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain.,Biochemistry and Molecular Genetics Department, Hospital Clinic, Barcelona, Spain.,Institut d'Investigació Biomèdica August Pi i Sunyer IDIBAPS, Barcelona, Spain
| | - Silvia Izquierdo-Álvarez
- Genetics Department of Clinical Biochemistry, Hospital Universitario Miguel Servet, Zaragoza, Spain
| | - María Isabel Tejada
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain.,Genetics Service, Cruces University Hospital, Osakidetza Basque Health Service, Barakaldo, Spain.,Centre for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
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Tejada MI, Ibarluzea N. Non-syndromic X linked intellectual disability: Current knowledge in light of the recent advances in molecular and functional studies. Clin Genet 2020; 97:677-687. [PMID: 31898314 DOI: 10.1111/cge.13698] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 12/09/2019] [Accepted: 12/24/2019] [Indexed: 12/23/2022]
Abstract
Since the discovery of the FMR1 gene and the clinical and molecular characterization of Fragile X Syndrome in 1991, more than 141 genes have been identified in the X-chromosome in these 28 years thanks to applying continuously evolving molecular techniques to X-linked intellectual disability (XLID) families. In the past decade, array comparative genomic hybridization and next generation sequencing technologies have accelerated gene discovery exponentially. Classically, XLID has been subdivided in syndromic intellectual disability (S-XLID)-where intellectual disability (ID) is always associated with other recognizable physical and/or neurological features-and non-specific or non-syndromic intellectual disability (NS-XLID) where the only common feature is ID. Nevertheless, new advances on the study of these entities have showed that this classification is not always clear-cut because distinct variants in several of these XLID genes can result in S-XLID as well as in NS-XLID. This review focuses on the current knowledge on the XLID genes involved in non-syndromic forms, with the emphasis on their pathogenic mechanism, thus allowing the possibility to elucidate why some of them can give both syndromic and non-syndromic phenotypes.
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Affiliation(s)
- María Isabel Tejada
- Genetics Service, Cruces University Hospital, Osakidetza Basque Health Service, Barakaldo, Spain.,Biocruces-Bizkaia Health Research Institute, Barakaldo, Spain.,Clinical Group, Centre for Biomedical Research on Rare Diseases (CIBERER), Valencia, Spain
| | - Nekane Ibarluzea
- Biocruces-Bizkaia Health Research Institute, Barakaldo, Spain.,Clinical Group, Centre for Biomedical Research on Rare Diseases (CIBERER), Valencia, Spain
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Dean DD, Agarwal S, Muthuswamy S. Fragile X molecular investigation and genetic counseling of intellectual disability/developmental delay patients in an Indian scenario. Expert Rev Mol Diagn 2019; 19:641-649. [PMID: 31159589 DOI: 10.1080/14737159.2019.1622416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Background: Fragile X Syndrome (FXS), the most common cause of inherited intellectual disability (ID), is caused by a CGG repeat expansion (full mutation (FM), >200 CGG) at the Fragile X Mental Retardation 1 (FMR1) gene. Early identification of FXS has prognostic significance for affected individuals due to early initiation of interventions. Genetic counseling and family screening can aid parents and at-risk asymptomatic carriers (premutation (PM), 55-200 CGG) in taking proper reproductive decisions. Methodology: The present study utilizes Triplet Primed-Polymerase Chain Reaction (TP-PCR) methodology for detecting the repeat expansion at FMR1 gene in 233 Indian intellectual disability/developmental delay (ID/DD) patients. Results: We have identified 18/233 (7.7%) FXS positive cases. Early diagnosis was made in 66.7% cases (<10 years). Extended family screening in 14 affected individuals identified 9 additional FM cases (7 males and 2 females) and 23 carrier PM females, which otherwise could have been missed. Four prenatal diagnoses were also performed, leading to the identification of 1 PM and 1 FM carrier fetus. Conclusion: A high frequency (7.7%) of FXS among Indian ID/DD subjects obtained in this study depicted the need for more professional recommendations concerning prompt referral for genetic testing, and increased exposure to information about FXS to pediatricians.
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Affiliation(s)
- Deepika Delsa Dean
- a Department of Medical Genetics , Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGIMS) , Lucknow , UP , India
| | - Sarita Agarwal
- a Department of Medical Genetics , Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGIMS) , Lucknow , UP , India
| | - Srinivasan Muthuswamy
- a Department of Medical Genetics , Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGIMS) , Lucknow , UP , India
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Landowska A, Rzońca S, Bal J, Gos M. [Fragile X syndrome and FMR1-dependent diseases - clinical presentation, epidemiology and molecular background]. DEVELOPMENTAL PERIOD MEDICINE 2018; 22. [PMID: 29641417 PMCID: PMC8522919 DOI: 10.34763/devperiodmed.20182201.1421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Fragile X syndrome (FXS) is the second most common inherited cause of intellectual disability (ID), after Down syndrome. The severity of ID in FXS patients varies and depends mainly on the patient's sex. Besides intellectual disorders, additional symptoms, such as psychomotor delay, a specific behavioral phenotype, or emotional problems are present in FXS patients. In over 99% of the cases, the disease is caused by the presence of a dynamic mutation in the FMR1 gene localized on the X chromosome. Due to the expansion of CGG nucleotides (over 200 repeats), FMR1 gene expression is decreased and results in the significant reduction of the FMRP protein level. The CGG expansion to premutation range (55-200 CGG repeats) is equivalent to the FXS carrier status and may cause FMR1-dependent disorders - fragile X-associated primary ovarian insufficiency (FXPOI) and fragile X-associated tremor/ataxia syndrome (FXTAS). In contrast to FXS, clinical symptoms of these diseases occur later in adulthood. The aim of the article is to present the knowledge about the molecular background and epidemiology of fragile X syndrome and other FMR1-related disorders.
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Affiliation(s)
- Aleksandra Landowska
- Zakład Genetyki Medycznej, Instytut Matki i Dziecka, Warszawa, Polska,Aleksandra Landowska Zakład Genetyki Medycznej, Instytut Matki i Dziecka ul. Kasprzaka 17a, 01-211 Warszawa tel. (+48 22) 327-71-76
| | - Sylwia Rzońca
- Zakład Genetyki Medycznej, Instytut Matki i Dziecka, Warszawa, Polska
| | - Jerzy Bal
- Zakład Genetyki Medycznej, Instytut Matki i Dziecka, Warszawa, Polska
| | - Monika Gos
- Zakład Genetyki Medycznej, Instytut Matki i Dziecka, Warszawa, Polska
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Merino S, Ibarluzea N, Maortua H, Prieto B, Rouco I, López-Aríztegui MA, Tejada MI. Associated Clinical Disorders Diagnosed by Medical Specialists in 188 FMR1 Premutation Carriers Found in the Last 25 Years in the Spanish Basque Country: A Retrospective Study. Genes (Basel) 2016; 7:genes7100090. [PMID: 27775646 PMCID: PMC5083929 DOI: 10.3390/genes7100090] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 10/12/2016] [Accepted: 10/14/2016] [Indexed: 12/30/2022] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) and fragile X-associated primary ovarian insufficiency (FXPOI) are definitely related to the fragile X mental retardation 1 (FMR1) premutation (PM). Additional medical problems have also been associated with the PM, such as fibromyalgia, endocrine, and psychiatric disorders. To improve our understanding in the field, we reviewed all PM carriers and their reasons for any medical referrals from 104 fragile X families molecularly diagnosed in our laboratory and living in the Spanish Basque Country. After signing the written informed consent, we studied their electronic medical records in order to identify the disorders associated with the PM and their frequencies. We obtained clinical data in 188 PM carriers (147 women and 41 men). In women, the frequency of FXPOI (22.61%) was similar to that previously reported in PM carriers. In men, the frequency of definite FXTAS (28.57%) was lower than reported elsewhere. Furthermore, thyroid pathology was associated with the PM, the frequency of hypothyroidism being much higher in the studied region than in the general population (8.84% vs. 0.93%). Finally, we found no association with fibromyalgia or psychiatric problems. These findings represent another population contribution in this field and may be useful for the clinical management of PM carriers.
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Affiliation(s)
- Sonia Merino
- Molecular Genetics Laboratory, Genetics Service, BioCruces Health Research Institute, Cruces University Hospital, 48903-Barakaldo-Bizkaia, Spain.
| | - Nekane Ibarluzea
- Molecular Genetics Laboratory, Genetics Service, BioCruces Health Research Institute, Cruces University Hospital, 48903-Barakaldo-Bizkaia, Spain.
| | - Hiart Maortua
- Molecular Genetics Laboratory, Genetics Service, BioCruces Health Research Institute, Cruces University Hospital, 48903-Barakaldo-Bizkaia, Spain.
- Clinical Group Affiliated with the Centre for Biomedical Research on Rare Diseases (CIBERER), 46010-Valencia, Spain.
| | - Begoña Prieto
- Human Reproduction Unit, Obstetrics and Gynecology Department, BioCruces Health Research Institute, Cruces University Hospital, 48903-Barakaldo-Bizkaia, Spain.
| | - Idoia Rouco
- Ataxias and Spastic Paraplegias Unit, Neurology Department, BioCruces Health Research Institute, Cruces University Hospital, 48903-Barakaldo-Bizkaia, Spain.
| | - Maria-Asunción López-Aríztegui
- Clinical Group Affiliated with the Centre for Biomedical Research on Rare Diseases (CIBERER), 46010-Valencia, Spain.
- Genetics Counseling, Genetics Service, BioCruces Health Research Institute, Cruces University Hospital, 48903-Barakaldo-Bizkaia, Spain.
| | - Maria-Isabel Tejada
- Molecular Genetics Laboratory, Genetics Service, BioCruces Health Research Institute, Cruces University Hospital, 48903-Barakaldo-Bizkaia, Spain.
- Clinical Group Affiliated with the Centre for Biomedical Research on Rare Diseases (CIBERER), 46010-Valencia, Spain.
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Greiss Hess L, Fitzpatrick SE, Nguyen DV, Chen Y, Gaul KN, Schneider A, Lemons Chitwood K, Eldeeb MAAA, Polussa J, Hessl D, Rivera S, Hagerman RJ. A Randomized, Double-Blind, Placebo-Controlled Trial of Low-Dose Sertraline in Young Children With Fragile X Syndrome. J Dev Behav Pediatr 2016; 37:619-28. [PMID: 27560971 PMCID: PMC5039060 DOI: 10.1097/dbp.0000000000000334] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Observational studies and anecdotal reports suggest that sertraline, a selective serotonin reuptake inhibitor, may improve language development in young children with fragile X syndrome (FXS). METHODS The authors evaluated the efficacy of 6 months of treatment with low-dose sertraline in a randomized, double-blind, placebo-controlled trial in 52 children with FXS aged 2 to 6 years. RESULTS Eighty-one subjects were screened for eligibility, and 57 were randomized to sertraline (27) or placebo (30). Two subjects from the sertraline arm and 3 from the placebo arm discontinued. Intent-to-treat analysis showed no difference from placebo on the primary outcomes: the Mullen Scales of Early Learning (MSEL) expressive language (EL) age equivalent and Clinical Global Impression Scale-Improvement. However, analyses of secondary measures showed significant improvements, particularly in motor and visual perceptual abilities and social participation. Sertraline was well tolerated, with no difference in side effects between sertraline and placebo groups. No serious adverse events occurred. CONCLUSION This randomized controlled trial of 6 months of sertraline treatment showed no primary benefit with respect to early EL development and global clinical improvement. However, in secondary exploratory analyses, there were significant improvements seen on motor and visual perceptual subtests, the cognitive T score sum on the MSEL, and on one measure of social participation on the Sensory Processing Measure-Preschool. Furthermore, post hoc analysis found significant improvement in early EL development as measured by the MSEL among children with autism spectrum disorder on sertraline. Treatment appears safe for this 6-month period in young children with FXS, but the authors do not know the long-term side effects of this treatment. These results warrant further studies of sertraline in young children with FXS using refined outcome measures as well as longer term follow-up studies to address long-term side effects of low-dose sertraline in early childhood.
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Affiliation(s)
- Laura Greiss Hess
- *Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis Medical Center, Sacramento, CA; †Department of Occupational Therapy, Dominican University of California, San Rafael, CA; ‡Department of Neuroscience, The Ohio State University, Columbus, OH; §Department of Medicine, University of California, Irvine School of Medicine, Orange, CA; ‖Institute for Clinical and Translational Science, University of California, Irvine, CA; ¶Department of Psychology, University of California, Davis, Davis, CA; **Department of Pediatrics, University of California, Davis Medical Center, Sacramento, CA; ††Department of Special Education, California State University, Monterey Bay, CA; ‡‡Department of Psychiatry and Behavioral Sciences, University of California, Davis Medical Center, Sacramento, CA
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FMR1 gene mutations in patients with fragile X syndrome and obligate carriers: 30 years of experience in Chile. Genet Res (Camb) 2016; 98:e11. [PMID: 27350105 DOI: 10.1017/s0016672316000082] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common form of inherited intellectual disability (ID) and co-morbid autism. It is caused by an amplification of the CGG repeat (>200), which is known as the full mutation, within the 5'UTR of the FMR1 gene. Expansions between 55-200 CGG repeats are termed premutation and are associated with a greater risk for fragile X-associated tremor/ataxia syndrome and fragile X-associated premature ovarian insufficiency. Intermediate alleles, also called the grey zone, include approximately 45-54 repeats and are considered borderline. Individuals with less than 45 repeats have a normal FMR1 gene. We report the occurrence of CGG expansions of the FMR1 gene in Chile among patients with ID and families with a known history of FXS. Here, we present a retrospective review conducted on 2321 cases (2202 probands and 119 relatives) referred for FXS diagnosis and cascade screening at the Institute of Nutrition and Food Technology (INTA), University of Chile. Samples were analysed using traditional cytogenetic methods and/or PCR. Southern blot was used to confirm the diagnosis. Overall frequency of FMR1 expansions observed among probands was 194 (8·8%), the average age of diagnosis was 8·8 ± 5·4 years. Of 119 family members studied, 72 (60%) were diagnosed with a CGG expansion. Our results indicated that the prevalence of CGG expansions of the FMR1 gene among probands is relatively higher than other populations. The average age of diagnosis is also higher than reference values. PCR and Southern blot represent a reliable molecular technique in the diagnosis of FXS.
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González-Pérez J, Izquierdo-Álvarez S, Fuertes-Rodrigo C, Monge-Galindo L, Peña-Segura JL, López-Pisón FJ. [Triplet expansion cytosine-guanine-guanine: Three cases of OMIM syndrome in the same family]. Med Clin (Barc) 2016; 146:311-5. [PMID: 26776484 DOI: 10.1016/j.medcli.2015.11.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Revised: 11/18/2015] [Accepted: 11/19/2015] [Indexed: 11/25/2022]
Abstract
INTRODUCTION The dynamic increase in the number of triplet repeats of cytosine-guanine-guanine (CGG) in the FMR1 gene mutation is responsible for three OMIM syndromes with a distinct clinical phenotype: Fragile X syndrome (FXS) and two pathologies in adult carriers of the premutation (55-200 CGG repeats): Primary ovarian insufficiency (FXPOI) and tremor-ataxia syndrome (FXTAS) associated with FXS. CLINICAL OBSERVATION AND METHODS CGG mutation dynamics of the FMR1 gene were studied in DNA samples from peripheral blood from the index case and other relatives of first, second and third degree by TP-PCR, and the percentage methylation. RESULTS Diagnosis of FXS was confirmed in three patients (21.4%), eight patients (57.1%) were confirmed in the premutation range transmitters, one male patient with full mutation/permutation mosaicism (7.1%) and two patients (14.3%) with normal study. Of the eight permutated patients, three had FXPOI and one male patient had FXTAS. DISCUSSION Our study suggests the importance of making an early diagnosis of SXF in order to carry out a family study and genetic counselling, which allow the identification of new cases or premutated patients with FMR1 gene- associated syndromes (FXTAS, FXPOI).
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Affiliation(s)
- Jesús González-Pérez
- Unidad de Neuropediatría, Servicio de Pediatría, Hospital Universitario Miguel Servet, Zaragoza, Spain.
| | - Silvia Izquierdo-Álvarez
- Sección de Genética Clínica y Reproducción Asistida, Servicio de Bioquímica Clínica, Hospital Universitario Miguel Servet, Zaragoza, Spain
| | - Cristina Fuertes-Rodrigo
- Unidad de Neuropediatría, Servicio de Pediatría, Hospital Universitario Miguel Servet, Zaragoza, Spain
| | - Lorena Monge-Galindo
- Unidad de Neuropediatría, Servicio de Pediatría, Hospital Universitario Miguel Servet, Zaragoza, Spain
| | - José Luis Peña-Segura
- Unidad de Neuropediatría, Servicio de Pediatría, Hospital Universitario Miguel Servet, Zaragoza, Spain
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Hanson AC, Hagerman RJ. Serotonin dysregulation in Fragile X Syndrome: implications for treatment. Intractable Rare Dis Res 2014; 3:110-7. [PMID: 25606361 PMCID: PMC4298641 DOI: 10.5582/irdr.2014.01027] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 11/28/2014] [Indexed: 12/29/2022] Open
Abstract
Fragile X Syndrome (FXS) is a trinucleotide repeat disorder that results in the silencing of the Fragile X Mental Retardation 1 gene (FMR1), leading to a lack of the FMR1 protein (FMRP). FMRP is an mRNA-binding protein that regulates the translation of hundreds of mRNAs important for synaptic plasticity. Several of these pathways have been identified and have guided the development of targeted treatments for FXS. Here we present evidence that serotonin is dysregulated in FXS and treatment with the selective serotonin reuptake inhibitor (SSRI) sertraline may be beneficial for individuals with FXS, particularly in early childhood.
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Affiliation(s)
| | - Randi J Hagerman
- UC Davis MIND Institute and Department of Pediatrics, UC Davis Medical Center, Sacramento, CA, USA
- Address correspondence to: Dr. Randi J. Hagerman, UC Davis MIND Institute and Department of Pediatrics, UC Davis Medical Center, Sacramento, CA 95817, USA. E-mail:
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