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Baker EK, Arpone M, Bui M, Kraan CM, Ling L, Francis D, Hunter MF, Rogers C, Field MJ, Santa María L, Faundes V, Curotto B, Morales P, Trigo C, Salas I, Alliende AM, Amor DJ, Godler DE. Tissue mosaicism, FMR1 expression and intellectual functioning in males with fragile X syndrome. Am J Med Genet A 2023; 191:357-369. [PMID: 36349505 PMCID: PMC10952635 DOI: 10.1002/ajmg.a.63027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 09/13/2022] [Accepted: 10/13/2022] [Indexed: 11/10/2022]
Abstract
Fragile X syndrome (FXS) is caused by hypermethylation of the FMR1 promoter due to the full mutation expansion (full mutation [FM]: CGG ≥ 200 repeats) and silencing of FMR1. Assessment of mosaicism for active-unmethylated alleles has prognostic utility. This study examined relationships between FMR1 methylation in different tissues with FMR1 messenger ribonucleic acid (mRNA) and intellectual functioning in 87 males with FXS (1.89-43.17 years of age). Methylation sensitive Southern blot (mSB) and Methylation Specific-Quantitative Melt Aanalysis (MS-QMA) were used to examine FMR1 methylation. FMR1 mRNA levels in blood showed strong relationships with FMR1 methylation assessed using MS-QMA in blood (n = 68; R2 = 0.597; p = 1.4 × 10-10 ) and buccal epithelial cells (BEC) (n = 62; R2 = 0.24; p = 0.003), with these measures also showing relationships with intellectual functioning scores (p < 0.01). However, these relationships were not as strong for mSB, with ~40% of males with only FM alleles that were 100% methylated and non-mosaic by mSB, showing methylation mosaicism by MS-QMA. This was confirmed through presence of detectable levels of FMR1 mRNA in blood. In summary, FMR1 methylation levels in blood and BEC examined by MS-QMA were significantly associated with FMR1 mRNA levels and intellectual functioning in males with FXS. These relationships were not as strong for mSB, which underestimated prevalence of mosaicism.
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Affiliation(s)
- Emma K. Baker
- Diagnosis and Development, Murdoch Children's Research InstituteRoyal Children's HospitalMelbourneVictoriaAustralia
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health SciencesUniversity of MelbourneParkvilleVictoriaAustralia
- School of Psychology and Public HealthLa Trobe UniversityBundooraVictoriaAustralia
| | - Marta Arpone
- Diagnosis and Development, Murdoch Children's Research InstituteRoyal Children's HospitalMelbourneVictoriaAustralia
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health SciencesUniversity of MelbourneParkvilleVictoriaAustralia
- Brain and Mind, Murdoch Children's Research InstituteRoyal Children's HospitalParkvilleVictoriaAustralia
| | - Minh Bui
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global HealthUniversity of MelbourneMelbourneVictoriaAustralia
| | - Claudine M. Kraan
- Diagnosis and Development, Murdoch Children's Research InstituteRoyal Children's HospitalMelbourneVictoriaAustralia
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health SciencesUniversity of MelbourneParkvilleVictoriaAustralia
| | - Ling Ling
- Diagnosis and Development, Murdoch Children's Research InstituteRoyal Children's HospitalMelbourneVictoriaAustralia
| | - David Francis
- Victorian Clinical Genetics Services and Murdoch Children's Research InstituteThe Royal Children's HospitalMelbourneVictoriaAustralia
| | - Mathew F. Hunter
- Monash GeneticsMonash HealthClaytonVictoriaAustralia
- Department of PaediatricsMonash UniversityClaytonVictoriaAustralia
| | - Carolyn Rogers
- Genetics of Learning Disability ServiceHunter GeneticsWaratahNew South WalesAustralia
| | - Michael J. Field
- Genetics of Learning Disability ServiceHunter GeneticsWaratahNew South WalesAustralia
| | - Lorena Santa María
- Molecular and Cytogenetics LaboratoryINTA University of ChileSantiagoChile
| | - Víctor Faundes
- Molecular and Cytogenetics LaboratoryINTA University of ChileSantiagoChile
| | - Bianca Curotto
- Molecular and Cytogenetics LaboratoryINTA University of ChileSantiagoChile
| | - Paulina Morales
- Molecular and Cytogenetics LaboratoryINTA University of ChileSantiagoChile
| | - Cesar Trigo
- Molecular and Cytogenetics LaboratoryINTA University of ChileSantiagoChile
| | - Isabel Salas
- Molecular and Cytogenetics LaboratoryINTA University of ChileSantiagoChile
| | | | - David J. Amor
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health SciencesUniversity of MelbourneParkvilleVictoriaAustralia
- Neurodisability and Rehabilitation, Murdoch Children's Research InstituteRoyal Children's HospitalMelbourneVictoriaAustralia
| | - David E. Godler
- Diagnosis and Development, Murdoch Children's Research InstituteRoyal Children's HospitalMelbourneVictoriaAustralia
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health SciencesUniversity of MelbourneParkvilleVictoriaAustralia
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2
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Arpone M, Bretherton L, Amor DJ, Hearps SJC, Rogers C, Field MJ, Hunter MF, Santa Maria L, Alliende AM, Slee J, Godler DE, Baker EK. Agreement between parents' and clinical researchers' ratings of behavioral problems in children with fragile X syndrome and chromosome 15 imprinting disorders. RESEARCH IN DEVELOPMENTAL DISABILITIES 2022; 131:104338. [PMID: 36179574 DOI: 10.1016/j.ridd.2022.104338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 08/04/2022] [Accepted: 09/12/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Despite the increasing number of clinical trials involving children with neurodevelopmental disorders, appropriate and objective outcome measures for behavioral symptoms are still required. AIM This study assessed the agreement between parents' and clinical researchers' ratings of behavioral problem severity in children with fragile X syndrome (FXS) and chromosome 15 imprinting disorders. METHODS AND PROCEDURES The cohort comprised 123 children (64% males), aged 3-17 years, with FXS (n = 79), Prader-Willi (PWS; n = 19), Angelman (AS; n = 15), and Chromosome 15q duplication (n = 10) syndromes. Specific items from the Autism Diagnostic Observation Schedule-Second Edition and Aberrant Behavior Checklist-Community Edition mapping to corresponding behavioral domains were selected ad-hoc, to assess behavioral problems. OUTCOMES AND RESULTS Inter-rater agreement for the cohort was slight for self-injury (Intraclass Correlation Coefficient (ICC) = 0.12), fair for tantrums/aggression (0.24) and mannerisms/stereotypies (0.25), and moderate for hyperactivity (0.48). When stratified by diagnosis, ICC ranged from poor (0; self-injury, AS and PWS) to substantial (0.48; hyperactivity, females with FXS). CONCLUSIONS AND IMPLICATIONS The high level of inter-rater disagreement across most domains suggests that parents' and researchers' assessments led to discrepant appraisal of behavioral problem severity. These findings have implications for treatment targets and outcome measure selection in clinical trials, supporting a multi-informant approach.
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Affiliation(s)
- Marta Arpone
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia; Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia; Brain and Mind, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia
| | - Lesley Bretherton
- Brain and Mind, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia
| | - David J Amor
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia; Neurodisability and Rehabilitation, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia
| | - Stephen J C Hearps
- Brain and Mind, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia; Department of Critical Care, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Carolyn Rogers
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, NSW, Australia
| | - Michael J Field
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, NSW, Australia
| | - Matthew F Hunter
- Monash Genetics, Monash Health, Melbourne, VIC, Australia; Department of Paediatrics, Monash University, Melbourne, VIC, Australia
| | - Lorena Santa Maria
- Laboratory of Molecular Cytogenetics, Department of Genetics and Metabolic Diseases, Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile
| | - Angelica M Alliende
- Laboratory of Molecular Cytogenetics, Department of Genetics and Metabolic Diseases, Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile
| | - Jennie Slee
- Department of Health, Government of Western Australia, Genetic Services of Western Australia, Perth, Australia
| | - David E Godler
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia; Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Emma K Baker
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia; Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia; School of Psychology and Public Health, La Trobe University, Bundoora, VIC, Australia.
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3
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Bartlett E, Archibald AD, Francis D, Ling L, Thomas R, Chandler G, Ward L, O'Farrell G, Pandelache A, Delatycki MB, Bennetts BH, Ho G, Fisk K, Baker EK, Amor DJ, Godler DE. Paternal retraction of a fragile X allele to normal size, showing normal function over two generations. Am J Med Genet A 2021; 188:304-309. [PMID: 34545686 DOI: 10.1002/ajmg.a.62500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 08/09/2021] [Accepted: 08/18/2021] [Indexed: 11/09/2022]
Abstract
The FMR1 premutation (PM:55-199 CGG) is associated with fragile X-associated tremor/ataxia syndrome (FXTAS) and when maternally transmitted is at risk of expansion to a hypermethylated full mutation (FM: ≥ 200 CGG) that causes fragile X syndrome (FXS). We describe a maternally transmitted PM (77 CGG) that was passed to a son (103 CGG), and to a daughter (220-1822 CGG), who were affected with FXTAS and FXS, respectively. The male with the PM showed low-level mosaicism for normal size of 30 and 37 CGG. This male had two offspring: one female mosaic for PM and FM (56, 157, >200 CGG) and another with only a 37 CGG allele detected in multiple tissues, neither with a clinical phenotype. The female with the 37 CGG allele showed normal levels of FMR1 methylation and mRNA and passed this 37 CGG allele to one of her daughters, who was also unaffected. These findings show that post-zygotic paternal retraction can lead to low-level mosaicism for normal size alleles, with these normal alleles being functional when passed over two generations.
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Affiliation(s)
- Essra Bartlett
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Alison D Archibald
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia.,Bruce Lefroy Centre, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - David Francis
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Ling Ling
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Rob Thomas
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Gabrielle Chandler
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Lisa Ward
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Gemma O'Farrell
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Alison Pandelache
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Martin B Delatycki
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia.,Bruce Lefroy Centre, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Bruce H Bennetts
- Sydney Genome Diagnostics-Molecular Genetics, Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Discipline of Genetic Medicine, Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Gladys Ho
- Sydney Genome Diagnostics-Molecular Genetics, Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Discipline of Genetic Medicine, Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Katrina Fisk
- Sydney Genome Diagnostics-Molecular Genetics, Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Emma K Baker
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia.,School of Psychology and Public Health, La Trobe University, Melbourne, Victoria, Australia
| | - David J Amor
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia.,Neurodisability and Rehabilitation, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - David E Godler
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
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Baker EK, Arora S, Amor DJ, Date P, Cross M, O'Brien J, Simons C, Rogers C, Goodall S, Slee J, Cahir C, Godler DE. The Cost of Raising Individuals with Fragile X or Chromosome 15 Imprinting Disorders in Australia. J Autism Dev Disord 2021; 53:1682-1692. [PMID: 34292487 DOI: 10.1007/s10803-021-05193-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/08/2021] [Indexed: 11/29/2022]
Abstract
The study characterised differences in costs associated with raising a child between four rare disorders and examined the associations between these costs with clinical severity. Caregivers of 108 individuals with Prader-Willi, Angelman (AS), Chromosome 15q Duplication and fragile X (FXS) syndromes completed a modified Client Services Receipt Inventory and participants completed intellectual/developmental functioning and autism assessments. AS incurred the highest yearly costs per individual ($AUD96,994), while FXS had the lowest costs ($AUD33,221). Intellectual functioning negatively predicted total costs, after controlling for diagnosis. The effect of intellectual functioning on total costs for those with AS was significantly different to the other syndromes. The study highlights the significant costs associated with these syndromes, particularly AS, linked with severity of intellectual functioning.
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Affiliation(s)
- Emma K Baker
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, 50 Flemington Road, Parkville, VIC, 3052, Australia.,Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia.,School of Psychology and Public Health, La Trobe University, Bundoora, VIC, Australia
| | - Sheena Arora
- Centre for Health Economics Research and Evaluation, University of Technology Sydney, Broadway, NSW, Australia
| | - David J Amor
- Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia.,Neurodisability and Rehabilitation, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia
| | - Perrin Date
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, 50 Flemington Road, Parkville, VIC, 3052, Australia.,Olga Tennison Autism Research Centre, La Trobe University, Melbourne, VIC, Australia
| | - Meagan Cross
- Foundation for Angelman Syndrome Therapeutics (FAST), Salisbury, QLD, Australia
| | - James O'Brien
- Prader-Willi Syndrome Australia Ltd, Melbourne, VIC, Australia
| | - Chloe Simons
- Foundation for Angelman Syndrome Therapeutics (FAST), Salisbury, QLD, Australia
| | - Carolyn Rogers
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, NSW, Australia
| | - Stephen Goodall
- Centre for Health Economics Research and Evaluation, University of Technology Sydney, Broadway, NSW, Australia
| | - Jennie Slee
- Department of Health, Government of Western Australia, Genetic Services of Western Australia, Perth, WA, Australia
| | - Chris Cahir
- Dup15q Australia Ltd, Melbourne, VIC, Australia
| | - David E Godler
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, 50 Flemington Road, Parkville, VIC, 3052, Australia. .,Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia.
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Detection of Cryptic Fragile X Full Mutation Alleles by Southern Blot in a Female and Her Foetal DNA via Chorionic Villus Sampling, Complicated by Mosaicism for 45,X0/46,XX/47,XXX. Genes (Basel) 2021; 12:genes12060798. [PMID: 34073864 PMCID: PMC8225079 DOI: 10.3390/genes12060798] [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: 04/08/2021] [Revised: 05/08/2021] [Accepted: 05/18/2021] [Indexed: 11/23/2022] Open
Abstract
We describe a female with a 72 CGG FMR1 premutation (PM) (CGG 55–199) and family history of fragile X syndrome (FXS), referred for prenatal testing. The proband had a high risk of having an affected pregnancy with a full mutation allele (FM) (CGG > 200), that causes FXS through hypermethylation of the FMR1 promoter. The CGG sizing analysis in this study used AmplideX triplet repeat primed polymerase chain reaction (TP-PCR) and long-range methylation sensitive PCR (mPCR). These methods detected a 73 CGG PM allele in the proband’s blood, and a 164 CGG PM allele in her male cultured chorionic villus sample (CVS). In contrast, the Southern blot analysis showed mosaicism for: (i) a PM (71 CGG) and an FM (285–768 CGG) in the proband’s blood, and (ii) a PM (165 CGG) and an FM (408–625 CGG) in the male CVS. The FMR1 methylation analysis, using an EpiTYPER system in the proband, showed levels in the range observed for mosaic Turner syndrome. This was confirmed by molecular and cytogenetic karyotyping, identifying 45,X0/46,XX/47,XXX lines. In conclusion, this case highlights the importance of Southern blot in pre- and postnatal testing for presence of an FM, which was not detected using AmplideX TP-PCR or mPCR in the proband and her CVS.
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Baker EK, Butler MG, Hartin SN, Ling L, Bui M, Francis D, Rogers C, Field MJ, Slee J, Gamage D, Amor DJ, Godler DE. Relationships between UBE3A and SNORD116 expression and features of autism in chromosome 15 imprinting disorders. Transl Psychiatry 2020; 10:362. [PMID: 33116122 PMCID: PMC7595031 DOI: 10.1038/s41398-020-01034-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 09/20/2020] [Accepted: 10/02/2020] [Indexed: 12/21/2022] Open
Abstract
Chromosome 15 (C15) imprinting disorders including Prader-Willi (PWS), Angelman (AS) and chromosome 15 duplication (Dup15q) syndromes are severe neurodevelopmental disorders caused by abnormal expression of genes from the 15q11-q13 region, associated with abnormal DNA methylation and/or copy number changes. This study compared changes in mRNA levels of UBE3A and SNORD116 located within the 15q11-q13 region between these disorders and their subtypes and related these to the clinical phenotypes. The study cohort included 58 participants affected with a C15 imprinting disorder (PWS = 27, AS = 21, Dup15q = 10) and 20 typically developing controls. Semi-quantitative analysis of mRNA from peripheral blood mononuclear cells (PBMCs) was performed using reverse transcription droplet digital polymerase chain reaction (PCR) for UBE3A and SNORD116 normalised to a panel of internal control genes determined using the geNorm approach. Participants completed an intellectual/developmental functioning assessment and the Autism Diagnostic Observation Schedule-2nd Edition. The Dup15q group was the only condition with significantly increased UBE3A mRNA levels when compared to the control group (p < 0.001). Both the AS and Dup15q groups also had significantly elevated SNORD116 mRNA levels compared to controls (AS: p < 0.0001; Dup15q: p = 0.002). Both UBE3A and SNORD116 mRNA levels were positively correlated with all developmental functioning scores in the deletion AS group (p < 0.001), and autism features (p < 0.001) in the non-deletion PWS group. The findings suggest presence of novel interactions between expression of UBE3A and SNORD116 in PBMCs and brain specific processes underlying motor and language impairments and autism features in these disorders.
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Affiliation(s)
- Emma K Baker
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
- Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia
- School of Psychology and Public Health, La Trobe University, Melbourne, Victoria, Australia
| | - Merlin G Butler
- Department of Psychiatry, Behavioral Sciences and Pediatrics, University of Kansas Medical Centre, Kansas City, Kansas, USA
| | - Samantha N Hartin
- Department of Psychiatry, Behavioral Sciences and Pediatrics, University of Kansas Medical Centre, Kansas City, Kansas, USA
| | - Ling Ling
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Minh Bui
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
| | - David Francis
- Victorian Clinical Genetics Services and Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Carolyn Rogers
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, New South Wales, Australia
| | - Michael J Field
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, New South Wales, Australia
| | - Jennie Slee
- Department of Health, Government of Western Australia, Genetic Services of Western Australia, Perth, Western Australia, Australia
| | - Dinusha Gamage
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - David J Amor
- Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia
- Neurodisability and Rehabilitation, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - David E Godler
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.
- Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia.
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Kraan CM, Baker EK, Arpone M, Bui M, Ling L, Gamage D, Bretherton L, Rogers C, Field MJ, Wotton TL, Francis D, Hunter MF, Cohen J, Amor DJ, Godler DE. DNA Methylation at Birth Predicts Intellectual Functioning and Autism Features in Children with Fragile X Syndrome. Int J Mol Sci 2020; 21:ijms21207735. [PMID: 33086711 PMCID: PMC7589848 DOI: 10.3390/ijms21207735] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/15/2020] [Accepted: 10/16/2020] [Indexed: 12/12/2022] Open
Abstract
Fragile X syndrome (FXS) is a leading single-gene cause of intellectual disability (ID) with autism features. This study analysed diagnostic and prognostic utility of the Fragile X-Related Epigenetic Element 2 DNA methylation (FREE2m) assessed by Methylation Specific-Quantitative Melt Analysis and the EpiTYPER system, in retrospectively retrieved newborn blood spots (NBS) and newly created dried blood spots (DBS) from 65 children with FXS (~2–17 years). A further 168 NBS from infants from the general population were used to establish control reference ranges, in both sexes. FREE2m analysis showed sensitivity and specificity approaching 100%. In FXS males, NBS FREE2m strongly correlated with intellectual functioning and autism features, however associations were not as strong for FXS females. Fragile X mental retardation 1 gene (FMR1) mRNA levels in blood were correlated with FREE2m in both NBS and DBS, for both sexes. In females, DNAm was significantly increased at birth with a decrease in childhood. The findings support the use of FREE2m analysis in newborns for screening, diagnostic and prognostic testing in FXS.
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Affiliation(s)
- Claudine M Kraan
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne VIC 3052, Australia; (C.M.K.); (E.K.B.); (M.A.); (L.L.); (D.G.); (L.B.); (D.J.A.)
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville VIC 3052, Australia
| | - Emma K Baker
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne VIC 3052, Australia; (C.M.K.); (E.K.B.); (M.A.); (L.L.); (D.G.); (L.B.); (D.J.A.)
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville VIC 3052, Australia
- School of Psychology and Public Health, La Trobe University, Bundoora VIC 3086, Australia
| | - Marta Arpone
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne VIC 3052, Australia; (C.M.K.); (E.K.B.); (M.A.); (L.L.); (D.G.); (L.B.); (D.J.A.)
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville VIC 3052, Australia
- Brain and Mind, Murdoch Children’s Research Institute, Royal Children’s Hospital, Parkville VIC 3052, Australia
| | - Minh Bui
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne VIC 3052, Australia;
| | - Ling Ling
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne VIC 3052, Australia; (C.M.K.); (E.K.B.); (M.A.); (L.L.); (D.G.); (L.B.); (D.J.A.)
| | - Dinusha Gamage
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne VIC 3052, Australia; (C.M.K.); (E.K.B.); (M.A.); (L.L.); (D.G.); (L.B.); (D.J.A.)
| | - Lesley Bretherton
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne VIC 3052, Australia; (C.M.K.); (E.K.B.); (M.A.); (L.L.); (D.G.); (L.B.); (D.J.A.)
| | - Carolyn Rogers
- Genetics of Learning Disability Service (GOLD service), Hunter Genetics, Newcastle NSW 2298, Australia; (C.R.); (M.J.F.)
| | - Michael J Field
- Genetics of Learning Disability Service (GOLD service), Hunter Genetics, Newcastle NSW 2298, Australia; (C.R.); (M.J.F.)
| | - Tiffany L Wotton
- New South Wales Newborn Screening Program, Children’s Hospital at Westmead, Sydney NSW 2145, Australia;
| | - David Francis
- Victorian Clinical Genetics Services, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne VIC 3052, Australia;
| | - Matt F Hunter
- Monash Genetics, Monash Health, Clayton, VIC 3168, Australia;
| | - Jonathan Cohen
- Centre for Developmental Disability Health Victoria, Monash University, Doveton VIC 3177, Australia;
- Fragile X Alliance Inc., North Caulfield VIC 3161, Australia
| | - David J Amor
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne VIC 3052, Australia; (C.M.K.); (E.K.B.); (M.A.); (L.L.); (D.G.); (L.B.); (D.J.A.)
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville VIC 3052, Australia
| | - David E Godler
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne VIC 3052, Australia; (C.M.K.); (E.K.B.); (M.A.); (L.L.); (D.G.); (L.B.); (D.J.A.)
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville VIC 3052, Australia
- Correspondence: ; Tel.: +613-8341-6496
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FMR1 mRNA from full mutation alleles is associated with ABC-C FX scores in males with fragile X syndrome. Sci Rep 2020; 10:11701. [PMID: 32678152 PMCID: PMC7367290 DOI: 10.1038/s41598-020-68465-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 06/22/2020] [Indexed: 02/08/2023] Open
Abstract
Fragile X syndrome (FXS) is caused by a hypermethylated full mutation (FM) expansion with ≥ 200 CGG repeats, and a decrease in FMR1 mRNA and its protein. However, incomplete silencing from FM alleles has been associated with more severe autism features in FXS males. This study compared scores on the Aberrant Behavior Checklist-Community-FXS version (ABC-CFX) in 62 males affected with FXS (3 to 32 years) stratified based on presence or absence of mosaicism and/or FMR1 mRNA silencing. Associations between ABC-CFX subscales and FMR1 mRNA levels, assessed using real-time PCR relative standard curve method, were also examined. The FXS group mosaic for premutation (PM: 55–199 CGGs) and FM alleles had lower irritability (p = 0.014) and inappropriate speech (p < 0.001) scores compared to males with only FM alleles and complete loss of FMR1 mRNA. The PM/FM mosaic group also showed lower inappropriate speech scores compared to the incomplete silencing (p = 0.002) group. Increased FMR1 mRNA levels were associated with greater irritability (p < 0.001), and lower health-related quality of life scores (p = 0.004), but only in the incomplete silencing FM-only group. The findings suggest that stratification based on CGG sizing and FMR1 mRNA levels may be warranted in future research and clinical trials utilising ABC-CFX subscales as outcome measures.
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9
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Baker EK, Arpone M, Vera SA, Bretherton L, Ure A, Kraan CM, Bui M, Ling L, Francis D, Hunter MF, Elliott J, Rogers C, Field MJ, Cohen J, Maria LS, Faundes V, Curotto B, Morales P, Trigo C, Salas I, Alliende AM, Amor DJ, Godler DE. Intellectual functioning and behavioural features associated with mosaicism in fragile X syndrome. J Neurodev Disord 2019; 11:41. [PMID: 31878865 PMCID: PMC6933737 DOI: 10.1186/s11689-019-9288-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 11/07/2019] [Indexed: 02/06/2023] Open
Abstract
Background Fragile X syndrome (FXS) is a common cause of intellectual disability and autism spectrum disorder (ASD) usually associated with a CGG expansion, termed full mutation (FM: CGG ≥ 200), increased DNA methylation of the FMR1 promoter and silencing of the gene. Mosaicism for presence of cells with either methylated FM or smaller unmethylated pre-mutation (PM: CGG 55–199) alleles in the same individual have been associated with better cognitive functioning. This study compares age- and sex-matched FM-only and PM/FM mosaic individuals on intellectual functioning, ASD features and maladaptive behaviours. Methods This study comprised a large international cohort of 126 male and female participants with FXS (aged 1.15 to 43.17 years) separated into FM-only and PM/FM mosaic groups (90 males, 77.8% FM-only; 36 females, 77.8% FM-only). Intellectual functioning was assessed with age appropriate developmental or intelligence tests. The Autism Diagnostic Observation Schedule-2nd Edition was used to examine ASD features while the Aberrant Behavior Checklist-Community assessed maladaptive behaviours. Results Comparing males and females (FM-only + PM/FM mosaic), males had poorer intellectual functioning on all domains (p < 0.0001). Although females had less ASD features and less parent-reported maladaptive behaviours, these differences were no longer significant after controlling for intellectual functioning. Participants with PM/FM mosaicism, regardless of sex, presented with better intellectual functioning and less maladaptive behaviours compared with their age- and sex-matched FM-only counterparts (p < 0.05). ASD features were similar between FM-only and PM/FM mosaics within each sex, after controlling for overall intellectual functioning. Conclusions Males with FXS had significantly lower intellectual functioning than females with FXS. However, there were no significant differences in ASD features and maladaptive behaviours, after controlling for intellectual functioning, independent of the presence or absence of mosaicism. This suggests that interventions that primarily target cognitive abilities may in turn reduce the severity of maladaptive behaviours including ASD features in FXS.
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Affiliation(s)
- Emma K Baker
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia. .,Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia. .,School of Psychology and Public Health, La Trobe University, Bundoora, VIC, Australia.
| | - Marta Arpone
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia.,Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia.,Brain and Mind, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia
| | - Solange Aliaga Vera
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia
| | - Lesley Bretherton
- Brain and Mind, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia
| | - Alexandra Ure
- Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia.,Neurodisability and Rehabilitation, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia.,Royal Children's Hospital, Melbourne, VIC, Australia.,Department of Pediatrics, Monash University, Clayton, VIC, Australia
| | - Claudine M Kraan
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia.,Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
| | - Minh Bui
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Carlton, VIC, Australia
| | - Ling Ling
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia
| | - David Francis
- Victorian Clinical Genetics Services and Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia
| | - Matthew F Hunter
- Department of Pediatrics, Monash University, Clayton, VIC, Australia.,Monash Genetics, Monash Health, Melbourne, VIC, Australia
| | - Justine Elliott
- Victorian Clinical Genetics Services and Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia
| | - Carolyn Rogers
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, NSW, Australia
| | - Michael J Field
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, NSW, Australia
| | - Jonathan Cohen
- Fragile X Alliance Inc, Centre for Developmental Disability Health Victoria, Monash University, North Caulfield, Clayton, VIC, Australia
| | - Lorena Santa Maria
- Laboratory of Molecular Cytogenetics, Department of Genetics and Metabolic Diseases, Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile
| | - Victor Faundes
- Laboratory of Molecular Cytogenetics, Department of Genetics and Metabolic Diseases, Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile
| | - Bianca Curotto
- Laboratory of Molecular Cytogenetics, Department of Genetics and Metabolic Diseases, Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile
| | - Paulina Morales
- Laboratory of Molecular Cytogenetics, Department of Genetics and Metabolic Diseases, Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile
| | - Cesar Trigo
- Laboratory of Molecular Cytogenetics, Department of Genetics and Metabolic Diseases, Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile
| | - Isabel Salas
- Laboratory of Molecular Cytogenetics, Department of Genetics and Metabolic Diseases, Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile
| | - Angelica M Alliende
- Laboratory of Molecular Cytogenetics, Department of Genetics and Metabolic Diseases, Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile
| | - David J Amor
- Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia.,Neurodisability and Rehabilitation, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia
| | - David E Godler
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia.,Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
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10
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Hensel CH, Vanzo RJ, Martin MM, Ling L, Aliaga SM, Bui M, Francis DI, Twede H, Field MH, Morison JW, Amor DJ, Godler DE. Abnormally Methylated FMR1 in Absence of a Detectable Full Mutation in a U.S.A Patient Cohort Referred for Fragile X Testing. Sci Rep 2019; 9:15315. [PMID: 31653898 PMCID: PMC6814816 DOI: 10.1038/s41598-019-51618-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 09/30/2019] [Indexed: 12/11/2022] Open
Abstract
In 2016, Methylation-Specific Quantitative Melt Analysis (MS-QMA) on 3,340 male probands increased diagnostic yield from 1.60% to 1.84% for fragile X syndrome (FXS) using a pooling approach. In this study probands from Lineagen (UT, U.S.A.) of both sexes were screened using MS-QMA without sample pooling. The cohorts included: (i) 279 probands with no FXS full mutation (FM: CGG > 200) detected by AmplideX CGG sizing; (ii) 374 negative and 47 positive controls. MS-QMA sensitivity and specificity in controls approached 100% for both sexes. For male probands with no FM detected by standard testing (n = 189), MS-QMA identified abnormal DNA methylation (mDNA) in 4% normal size (NS: < 44 CGGs), 6% grey zone (CGG 45–54) and 12% premutation (CGG 54–199) alleles. The abnormal mDNA was confirmed by AmplideX methylation sensitive (m)PCR and EpiTYPER tests. In contrast, no abnormal mDNA was detected in 89 males with NS alleles from the general population. For females, 11% of 43 probands with NS alleles by the AmplideX sizing assay had abnormal mDNA by MS-QMA, with FM / NS mosaicism confirmed by AmplideX mPCR. FMR1 MS-QMA analysis can cost-effectively screen probands of both sexes for methylation and FM mosaicism that may be missed by standard testing.
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Affiliation(s)
| | - Rena J Vanzo
- Lineagen, Inc., Salt Lake City, UT, United States of America
| | - Megan M Martin
- Lineagen, Inc., Salt Lake City, UT, United States of America
| | - Ling Ling
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia
| | - Solange M Aliaga
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia
| | - Minh Bui
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, VIC, Australia
| | - David I Francis
- Victorian Clinical Genetics Services and Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia
| | - Hope Twede
- Lineagen, Inc., Salt Lake City, UT, United States of America
| | - Michael H Field
- Genetics of Learning Disability Service (GOLD service), Hunter Genetics, Newcastle, NSW, Australia
| | - Jonathon W Morison
- Business Development and Legal Office, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia
| | - David J Amor
- Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia.,Neurodisability and Rehabilitation Research Group, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia
| | - David E Godler
- Diagnosis and Development, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia. .,Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia.
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11
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Significantly Elevated FMR1 mRNA and Mosaicism for Methylated Premutation and Full Mutation Alleles in Two Brothers with Autism Features Referred for Fragile X Testing. Int J Mol Sci 2019; 20:ijms20163907. [PMID: 31405222 PMCID: PMC6721168 DOI: 10.3390/ijms20163907] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/04/2019] [Accepted: 08/07/2019] [Indexed: 11/26/2022] Open
Abstract
Although fragile X syndrome (FXS) is caused by a hypermethylated full mutation (FM) expansion with ≥200 cytosine-guanine-guanine (CGG) repeats, and a decrease in FMR1 mRNA and its protein (FMRP), incomplete silencing has been associated with more severe autism features in FXS males. This study reports on brothers (B1 and B2), aged 5 and 2 years, with autistic features and language delay, but a higher non-verbal IQ in comparison to typical FXS. CGG sizing using AmplideX PCR only identified premutation (PM: 55–199 CGGs) alleles in blood. Similarly, follow-up in B1 only revealed PM alleles in saliva and skin fibroblasts; whereas, an FM expansion was detected in both saliva and buccal DNA of B2. While Southern blot analysis of blood detected an unmethylated FM, methylation analysis with a more sensitive methodology showed that B1 had partially methylated PM alleles in blood and fibroblasts, which were completely unmethylated in buccal and saliva cells. In contrast, B2 was partially methylated in all tested tissues. Moreover, both brothers had FMR1 mRNA ~5 fold higher values than those of controls, FXS and PM cohorts. In conclusion, the presence of unmethylated FM and/or PM in both brothers may lead to an overexpression of toxic expanded mRNA in some cells, which may contribute to neurodevelopmental problems, including elevated autism features.
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12
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Baker EK, Arpone M, Aliaga SM, Bretherton L, Kraan CM, Bui M, Slater HR, Ling L, Francis D, Hunter MF, Elliott J, Rogers C, Field M, Cohen J, Cornish K, Santa Maria L, Faundes V, Curotto B, Morales P, Trigo C, Salas I, Alliende AM, Amor DJ, Godler DE. Incomplete silencing of full mutation alleles in males with fragile X syndrome is associated with autistic features. Mol Autism 2019; 10:21. [PMID: 31073396 PMCID: PMC6499941 DOI: 10.1186/s13229-019-0271-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 04/03/2019] [Indexed: 11/10/2022] Open
Abstract
Background Fragile X syndrome (FXS) is a common monogenic cause of intellectual disability with autism features. While it is caused by loss of the FMR1 product (FMRP), mosaicism for active and inactive FMR1 alleles, including alleles termed premutation (PM: 55-199 CGGs), is not uncommon. Importantly, both PM and active full mutation (FM: ≥ 200 CGGs) alleles often express elevated levels of mRNA that are thought to be toxic. This study determined if complete FMR1 mRNA silencing from FM alleles and/or levels of FMR1 mRNA (if present) in blood are associated with intellectual functioning and autism features in FXS. Methods The study cohort included 98 participants (70.4% male) with FXS (FM-only and PM/FM mosaic) aged 1-43 years. A control group of 14 females were used to establish control FMR1 mRNA reference range. Intellectual functioning and autism features were assessed using the Mullen Scales of Early Learning or an age-appropriate Wechsler Scale and the Autism Diagnostic Observation Schedule-2nd Edition (ADOS-2), respectively. FMR1 mRNA was analysed in venous blood collected at the time of assessments, using the real-time PCR relative standard curve method. Results Females with FXS had significantly higher levels of FMR1 mRNA (p < 0.001) than males. FMR1 mRNA levels were positively associated with age (p < 0.001), but not with intellectual functioning and autistic features in females. FM-only males (aged < 19 years) expressing FM FMR1 mRNA had significantly higher ADOS calibrated severity scores compared to FM-only males with completely silenced FMR1 (p = 0.011). However, there were no significant differences between these subgroups on intellectual functioning. In contrast, decreased levels of FMR1 mRNA were associated with decreased intellectual functioning in FXS males (p = 0.029), but not autism features, when combined with the PM/FM mosaic group. Conclusion Incomplete silencing of toxic FM RNA may be associated with autistic features, but not intellectual functioning in FXS males. While decreased levels of mRNA may be more predictive of intellectual functioning than autism features. If confirmed in future studies, these findings may have implications for patient stratification, outcome measure development, and design of clinical and pre-clinical trials in FXS.
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Affiliation(s)
- Emma K. Baker
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, 50 Flemington Rd, Parkville, VIC 3052 Australia
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Australia
| | - Marta Arpone
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, 50 Flemington Rd, Parkville, VIC 3052 Australia
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Australia
- Brain and Mind, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, Australia
| | - Solange M. Aliaga
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, 50 Flemington Rd, Parkville, VIC 3052 Australia
| | - Lesley Bretherton
- Brain and Mind, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, Australia
| | - Claudine M. Kraan
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, 50 Flemington Rd, Parkville, VIC 3052 Australia
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Australia
| | - Minh Bui
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Carlton, Australia
| | - Howard R. Slater
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, 50 Flemington Rd, Parkville, VIC 3052 Australia
| | - Ling Ling
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, 50 Flemington Rd, Parkville, VIC 3052 Australia
| | - David Francis
- Victorian Clinical Genetics Services and Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC Australia
| | - Matthew F. Hunter
- Monash Genetics, Monash Health, Melbourne, VIC Australia
- Department of Paediatrics, Monash University, Clayton, VIC Australia
| | - Justine Elliott
- Victorian Clinical Genetics Services and Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC Australia
| | - Carolyn Rogers
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, NSW Australia
| | - Michael Field
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, NSW Australia
| | - Jonathan Cohen
- Fragile X Alliance Inc, North Caulfield, VIC and Center for Developmental Disability Health Victoria, Monash University, Clayton, Australia
| | - Kim Cornish
- Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Clayton, VIC Australia
| | - Lorena Santa Maria
- Molecular and Cytogenetics Laboratory, INTA, University of Chile, Santiago, Chile
| | - Victor Faundes
- Molecular and Cytogenetics Laboratory, INTA, University of Chile, Santiago, Chile
| | - Bianca Curotto
- Molecular and Cytogenetics Laboratory, INTA, University of Chile, Santiago, Chile
| | - Paulina Morales
- Molecular and Cytogenetics Laboratory, INTA, University of Chile, Santiago, Chile
| | - Cesar Trigo
- Molecular and Cytogenetics Laboratory, INTA, University of Chile, Santiago, Chile
| | - Isabel Salas
- Molecular and Cytogenetics Laboratory, INTA, University of Chile, Santiago, Chile
| | - Angelica M. Alliende
- Molecular and Cytogenetics Laboratory, INTA, University of Chile, Santiago, Chile
| | - David J. Amor
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Australia
- Neurodisability and Rehabilitation, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, Australia
| | - David E. Godler
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, 50 Flemington Rd, Parkville, VIC 3052 Australia
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Australia
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Clinical and Molecular Differences between 4-Year-Old Monozygous Male Twins Mosaic for Normal, Premutation and Fragile X Full Mutation Alleles. Genes (Basel) 2019; 10:genes10040279. [PMID: 30959842 PMCID: PMC6523498 DOI: 10.3390/genes10040279] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 04/01/2019] [Accepted: 04/01/2019] [Indexed: 01/04/2023] Open
Abstract
This study describes monozygotic (MZ) male twins with fragile X syndrome (FXS), mosaic for normal size (NS: <44 CGGs), premutation (PM: 55–199 CGG) and full mutation (FM alleles ≥ 200) alleles, with autism. At 4 years of age chromosomal microarray confirmed monozygosity with both twins showing an XY sex complement. Normal size (30 CGG), PM (99 CGG) and FM (388–1632 CGGs) alleles were detected in Twin 1 (T1) by standard polymerase chain reaction (PCR) and Southern blot testing, while only PM (99 CGG) and FM (672–1025) alleles were identified in Twin 2 (T2). At ~5 years, T2 had greater intellectual impairments with a full scale IQ (FSIQ) of 55 and verbal IQ (VIQ) of 59, compared to FSIQ of 62 and VIQ of 78 for T1. This was consistent with the quantitative FMR1 methylation testing, revealing 10% higher methylation at 80% for T2; suggesting that less active unmethylated alleles were present in T2 as compared to T1. AmplideX methylation PCR also identified partial methylation, including an unmethylated NS allele in T2, undetected by standard testing. In conclusion, this report demonstrates significant differences in intellectual functioning between the MZ twins mosaic for NS, PM and FM alleles with partial FMR1 promoter methylation.
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14
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Kraan CM, Godler DE, Amor DJ. Epigenetics of fragile X syndrome and fragile X-related disorders. Dev Med Child Neurol 2019; 61:121-127. [PMID: 30084485 DOI: 10.1111/dmcn.13985] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/13/2018] [Indexed: 12/31/2022]
Abstract
The fragile X mental retardation 1 gene (FMR1)-related disorder fragile X syndrome (FXS) is the most common heritable form of cognitive impairment and the second most common cause of comorbid autism. FXS usually results when a premutation trinucleotide CGG repeat in the 5' untranslated region of the FMR1 gene (CGG 55-200) expands over generations to a full mutation allele (CGG >200). This expansion is associated with silencing of the FMR1 promoter via an epigenetic mechanism that involves DNA methylation of the CGG repeat and the surrounding regulatory regions. Decrease in FMR1 transcription is associated with loss of the FMR1 protein that is needed for typical brain development. The past decade has seen major advances in our understanding of the genetic and epigenetic processes that underlie FXS. Here we review these advances and their implications for diagnosis and treatment for individuals who have FMR1-related disorders. WHAT THIS PAPER ADDS: Improved analysis of DNA methylation allows better epigenetic evaluation of the fragile X gene. New testing techniques have unmasked interindividual variation among children with fragile X syndrome. New testing methods have also detected additional cases of fragile X.
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Affiliation(s)
- Claudine M Kraan
- Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia.,Department of Paediatrics, The University of Melbourne, Melbourne, Victoria, Australia
| | - David E Godler
- Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia.,Department of Paediatrics, The University of Melbourne, Melbourne, Victoria, Australia
| | - David J Amor
- Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia.,Department of Paediatrics, The University of Melbourne, Melbourne, Victoria, Australia
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15
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Prenatal Diagnosis of Fragile X Syndrome in a Twin Pregnancy Complicated by a Complete Retraction. Genes (Basel) 2018; 9:genes9060287. [PMID: 29880767 PMCID: PMC6027392 DOI: 10.3390/genes9060287] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 05/31/2018] [Accepted: 06/04/2018] [Indexed: 01/09/2023] Open
Abstract
Fragile X syndrome (FXS) is usually associated with a CGG repeat expansion >200 repeats within the FMR1 gene, known as a full mutation (FM). FM alleles produce abnormal methylation of the FMR1 promoter with reduction or silencing of FMR1 gene expression. Furthermore, premutation (PM: 55–199 CGGs) and full mutation alleles usually expand in size when maternally transmitted to progeny. This study describes a PM allele carried by the mother decreasing to a normal sized allele in a male from a dichorionic diamniotic (DCDA) twin pregnancy, with the female twin inheriting FM (200–790 CGGs), PM (130 CGGs) and normal-sized (39 CGGs) alleles. Further evidence of instability of the maternal PM allele was shown by a male proband (older brother) mosaic for PM (CGG 78 and 150 CGGs) and FM (200–813 CGGs), and a high level of FMR1 promoter methylation, between 50 and 70%, in multiple tissues. The fully-retracted, normal-sized allele was identified by PCR CGG sizing in the male twin, with no evidence of a FM allele identified using Southern blot analysis in multiple tissues collected postnatally and prenatally. Consistent with this, prenatal PCR sizing (35 CGGs) showed inconsistent inheritance of the maternal normal allele (30 CGGs), with single-nucleotide polymorphism (SNP) linkage analysis confirming that the abnormal FMR1 chromosome had been inherited from the mother’s PM chromosome. Importantly, the male twin showed no significant hypermethylation of the FMR1 promoter in all pre and postnatal tissues tested, as well as normal levels of FMR1 mRNA in blood. In summary, this report demonstrates the first postnatal follow up of a prenatal case in which FMR1 mRNA levels were approaching normal, with normal levels of FMR1 promoter methylation and normal CGG size in multiple pre and postnatally collected tissues.
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