1
|
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.
Collapse
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
| |
Collapse
|
2
|
Arif N, Shafiq Z, Mahmood K, Rafiq M, Naz S, Shahzad SA, Farooq U, Bahkali AH, Elgorban AM, Yaqub M, El-Gokha A. Synthesis, Biological Evaluation, and In Silico Studies of Novel Coumarin-Based 4 H,5 H-pyrano[3,2- c]chromenes as Potent β-Glucuronidase and Carbonic Anhydrase Inhibitors. ACS OMEGA 2022; 7:28605-28617. [PMID: 35990487 PMCID: PMC9386806 DOI: 10.1021/acsomega.2c03528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 07/26/2022] [Indexed: 06/15/2023]
Abstract
The search for novel heterocyclic compounds with a natural product skeleton as potent enzyme inhibitors against clinical hits is our prime concern in this study. Here, a simple and facile two-step strategy has been designed to synthesize a series of novel coumarin-based dihydropyranochromenes (12a-12m) in a basic moiety. The synthesized compounds were thus characterized through spectroscopic techniques and screened for inhibition potency against the cytosolic hCA II isoform and β-glucuronidase. Few of these compounds were potent inhibitors of hCA II and β-glucuronidase with varying IC50 values ranging from 4.55 ± 0.22 to 21.77 ± 3.32 μM and 440.1 ± 1.17 to 971.3 ± 0.05 μM, respectively. Among the stream of synthesized compounds, 12e and 12i were the most potent inhibitors of β-glucuronidase, while 12h, 12i, and 12j showed greater potency against hCA II. In silico docking studies illustrated the significance of substituted groups on the pyranochromene skeleton and binding pattern of these highly potent compounds inside enzyme pockets.
Collapse
Affiliation(s)
- Nadia Arif
- Institute
of Chemical Sciences, Organic Chemistry Division, Bahauddin Zakariya University, Multan 60800, Pakistan
| | - Zahid Shafiq
- Institute
of Chemical Sciences, Organic Chemistry Division, Bahauddin Zakariya University, Multan 60800, Pakistan
- Department
of Pharmaceutical & Medicinal Chemistry, University of Bonn, An der Immenburg 4, D-53121 Bonn, Germany
| | - Khalid Mahmood
- Institute
of Chemical Sciences, Organic Chemistry Division, Bahauddin Zakariya University, Multan 60800, Pakistan
| | - Muhammad Rafiq
- Institute
of Chemical Sciences, Organic Chemistry Division, Bahauddin Zakariya University, Multan 60800, Pakistan
| | - Sadia Naz
- Department
of Chemistry, COMSATS University Islamabad,
Abbottabad Campus, Abbottabad 22060, Pakistan
| | - Sohail Anjum Shahzad
- Department
of Chemistry, COMSATS University Islamabad,
Abbottabad Campus, Abbottabad 22060, Pakistan
| | - Umar Farooq
- Department
of Chemistry, COMSATS University Islamabad,
Abbottabad Campus, Abbottabad 22060, Pakistan
| | - Ali H. Bahkali
- Department
of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Abdallah M. Elgorban
- Department
of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Muhammad Yaqub
- Institute
of Chemical Sciences, Organic Chemistry Division, Bahauddin Zakariya University, Multan 60800, Pakistan
| | - Ahmed El-Gokha
- Department
of Pharmaceutical & Medicinal Chemistry, University of Bonn, An der Immenburg 4, D-53121 Bonn, Germany
- Chemistry
Department, Faculty of Science, Menoufia
University, Shebin El-Kom 32512, Egypt
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
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.
Collapse
|
6
|
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.
Collapse
|
7
|
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.
Collapse
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
| |
Collapse
|
8
|
β-glucuronidase use as a single internal control gene may confound analysis in FMR1 mRNA toxicity studies. PLoS One 2018; 13:e0192151. [PMID: 29474364 PMCID: PMC5825026 DOI: 10.1371/journal.pone.0192151] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 01/17/2018] [Indexed: 12/02/2022] Open
Abstract
Relationships between Fragile X Mental Retardation 1 (FMR1) mRNA levels in blood and intragenic FMR1 CGG triplet expansions support the pathogenic role of RNA gain of function toxicity in premutation (PM: 55–199 CGGs) related disorders. Real-time PCR (RT-PCR) studies reporting these findings normalised FMR1 mRNA level to a single internal control gene called β-glucuronidase (GUS). This study evaluated FMR1 mRNA-CGG correlations in 33 PM and 33 age- and IQ-matched control females using three normalisation strategies in peripheral blood mononuclear cells (PBMCs): (i) GUS as a single internal control; (ii) the mean of GUS, Eukaryotic Translation Initiation Factor 4A2 (EIF4A2) and succinate dehydrogenase complex flavoprotein subunit A (SDHA); and (iii) the mean of EIF4A2 and SDHA (with no contribution from GUS). GUS mRNA levels normalised to the mean of EIF4A2 and SDHA mRNA levels and EIF4A2/SDHA ratio were also evaluated. FMR1mRNA level normalised to the mean of EIF4A2 and SDHA mRNA levels, with no contribution from GUS, showed the most significant correlation with CGG size and the greatest difference between PM and control groups (p = 10−11). Only 15% of FMR1 mRNA PM results exceeded the maximum control value when normalised to GUS, compared with over 42% when normalised to the mean of EIF4A2 and SDHA mRNA levels. Neither GUS mRNA level normalised to the mean RNA levels of EIF4A2 and SDHA, nor to the EIF4A2/SDHA ratio were correlated with CGG size. However, greater variability in GUS mRNA levels were observed for both PM and control females across the full range of CGG repeat as compared to the EIF4A2/SDHA ratio. In conclusion, normalisation with multiple control genes, excluding GUS, can improve assessment of the biological significance of FMR1 mRNA-CGG size relationships.
Collapse
|
9
|
Shelton AL, Cornish KM, Godler D, Bui QM, Kolbe S, Fielding J. White matter microstructure, cognition, and molecular markers in fragile X premutation females. Neurology 2017; 88:2080-2088. [DOI: 10.1212/wnl.0000000000003979] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 02/14/2017] [Indexed: 01/06/2023] Open
Abstract
Objective:To examine the interrelationships between fragile X mental retardation 1 (FMR1) mRNA and the FMR1 exon 1/intron 1 boundary methylation, white matter microstructure, and executive function, in women with a FMR1 premutation expansion (PM; 55–199 CGG repeats) and controls (CGG < 44).Methods:Twenty women with PM without fragile X-associated tremor/ataxia syndrome (FXTAS) and 20 control women between 22 and 54 years of age completed this study. FMR1 mRNA and methylation levels for 9 CpG sites within the FMR1 exon 1/intron 1 boundary from peripheral blood samples were analyzed. To measure white matter microstructure, diffusion-weighted imaging was used, from which fractional anisotropy (FA) and mean diffusivity (MD) values from anatomic regions within the corpus callosum and cerebellar peduncles were extracted. Executive function was assessed across a range of tasks.Results:No differences were revealed in white matter microstructure between women with PM and controls. However, we reveal that for women with PM (but not controls), higher FMR1 mRNA correlated with lower MD values within the middle cerebellar peduncle and Paced Auditory Serial Addition Test scores, higher methylation of the FMR1 exon 1/intron 1 boundary correlated with lower MD within the inferior and middle cerebellar peduncles and longer prosaccade latencies, and higher FA values within the corpus callosum and cerebellar peduncle regions corresponded to superior executive function.Conclusions:We provide evidence linking white matter microstructure to executive dysfunction and elevated FMR1 mRNA and FMR1 exon 1/intron 1 boundary methylation in women with PM without FXTAS. This suggests that the FXTAS phenotype may not be distinct but may form part of a spectrum of PM involvement.
Collapse
|
10
|
Brain structure and intragenic DNA methylation are correlated, and predict executive dysfunction in fragile X premutation females. Transl Psychiatry 2016; 6:e984. [PMID: 27959330 PMCID: PMC5290342 DOI: 10.1038/tp.2016.250] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 09/28/2016] [Indexed: 02/07/2023] Open
Abstract
DNA methylation of the Fragile X mental retardation 1 (FMR1) exon 1/intron 1 boundary has been associated with executive dysfunction in female carriers of a FMR1 premutation (PM: 55-199 CGG repeats), whereas neuroanatomical changes have been associated with executive dysfunction in PM males. To our knowledge, this study for the first time examined the inter-relationships between executive function, neuroanatomical structure and molecular measures (DNA methylation and FMR1 mRNA levels in blood) in PM and control (<44 CGG repeats) females. In the PM group, FMR1 intron 1 methylation was positively associated with executive function and cortical thickness in middle and superior frontal gyri, and left inferior parietal gyrus. By contrast, in the control group, FMR1 intron 1 methylation was negatively associated with cortical thickness of the left middle frontal gyrus and superior frontal gyri. No significant associations were revealed for either group between FMR1 mRNA and neuroanatomical structure or executive function. In the PM group, the lack of any significant association between FMR1 mRNA levels and phenotypic measures found in this study suggests that either FMR1 expression is not well conserved between tissues, or that FMR1 intron 1 methylation is linked to neuroanatomical and cognitive phenotype in PM females via a different mechanism.
Collapse
|