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Pecorelli A, Cordone V, Schiavone ML, Caffarelli C, Cervellati C, Cerbone G, Gonnelli S, Hayek J, Valacchi G. Altered Bone Status in Rett Syndrome. Life (Basel) 2021; 11:life11060521. [PMID: 34205017 PMCID: PMC8230033 DOI: 10.3390/life11060521] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 05/31/2021] [Accepted: 06/02/2021] [Indexed: 11/24/2022] Open
Abstract
Rett syndrome (RTT) is a monogenic neurodevelopmental disorder primarily caused by mutations in X-linked MECP2 gene, encoding for methyl-CpG binding protein 2 (MeCP2), a multifaceted modulator of gene expression and chromatin organization. Based on the type of mutation, RTT patients exhibit a broad spectrum of clinical phenotypes with various degrees of severity. In addition, as a complex multisystem disease, RTT shows several clinical manifestations ranging from neurological to non-neurological symptoms. The most common non-neurological comorbidities include, among others, orthopedic complications, mainly scoliosis but also early osteopenia/osteoporosis and a high frequency of fractures. A characteristic low bone mineral density dependent on a slow rate of bone formation due to dysfunctional osteoblast activity rather than an increase in bone resorption is at the root of these complications. Evidence from human and animal studies supports the idea that MECP2 mutation could be associated with altered epigenetic regulation of bone-related factors and signaling pathways, including SFRP4/WNT/β-catenin axis and RANKL/RANK/OPG system. More research is needed to better understand the role of MeCP2 in bone homeostasis. Indeed, uncovering the molecular mechanisms underlying RTT bone problems could reveal new potential pharmacological targets for the treatment of these complications that adversely affect the quality of life of RTT patients for whom the only therapeutic approaches currently available include bisphosphonates, dietary supplements, and physical activity.
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Affiliation(s)
- Alessandra Pecorelli
- Animal Science Department, Plants for Human Health Institute, North Carolina State University, Kannapolis, NC 28081, USA;
- Correspondence: (A.P.); (G.V.)
| | - Valeria Cordone
- Department of Neuroscience and Rehabilitation, University of Ferrara, 44121 Ferrara, Italy;
| | - Maria Lucia Schiavone
- Animal Science Department, Plants for Human Health Institute, North Carolina State University, Kannapolis, NC 28081, USA;
| | - Carla Caffarelli
- Department of Medicine, Surgery and Neuroscience, University of Siena, Policlinico Le Scotte, 53100 Siena, Italy; (C.C.); (S.G.)
| | - Carlo Cervellati
- Department of Translational Medicine and for Romagna, University of Ferrara, 44121 Ferrara, Italy;
| | - Gaetana Cerbone
- Division of Medical Genetics, “S.G. Moscati” Hospital, 74100 Avellino, Italy;
| | - Stefano Gonnelli
- Department of Medicine, Surgery and Neuroscience, University of Siena, Policlinico Le Scotte, 53100 Siena, Italy; (C.C.); (S.G.)
| | - Joussef Hayek
- Toscana Life Sciences Foundation, 53100 Siena, Italy;
| | - Giuseppe Valacchi
- Animal Science Department, Plants for Human Health Institute, North Carolina State University, Kannapolis, NC 28081, USA;
- Department of Neuroscience and Rehabilitation, University of Ferrara, 44121 Ferrara, Italy;
- Department of Food and Nutrition, Kyung Hee University, Seoul 02447, Korea
- Correspondence: (A.P.); (G.V.)
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2
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Byiers BJ, Payen A, Feyma T, Panoskaltsis-Mortari A, Ehrhardt MJ, Symons FJ. Associations Among Diurnal Salivary Cortisol Patterns, Medication Use, and Behavioral Phenotype Features in a Community Sample of Rett Syndrome. AMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2020; 125:353-368. [PMID: 32936892 PMCID: PMC10699094 DOI: 10.1352/1944-7558-125.5.353] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 02/10/2020] [Indexed: 06/11/2023]
Abstract
Rett syndrome (RTT) is a severe neurodevelopmental disorder resulting from mutations of the MECP2 gene. Hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis and abnormal stress responses have been observed in animal models of RTT, but little is known about HPA axis function among individuals with RTT. Diurnal salivary cortisol patterns from 30 females with RTT were examined in relation to mutation type, medication use, and features of the RTT behavioral phenotype. Cortisol patterns were significantly related to mutation severity, anticonvulsant medication status, and bruxism (tooth grinding). This study provides preliminary support for the hypothesis that RTT may be at risk for outcomes associated with aberrant HPA axis function, and that this risk may be mediated by mutation type.
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Affiliation(s)
| | - Ameante Payen
- Breanne J. Byiers and Ameante Payen, University of Minnesota
| | - Timothy Feyma
- Timothy Feyma, Gillette Children's Specialty Healthcare, St. Paul, Minnesota
| | | | - Michael J Ehrhardt
- Angela Panoskaltsis-Mortari, Michael J. Ehrhardt, and Frank J. Symons, University of Minnesota
| | - Frank J Symons
- Angela Panoskaltsis-Mortari, Michael J. Ehrhardt, and Frank J. Symons, University of Minnesota
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3
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Fu C, Armstrong D, Marsh E, Lieberman D, Motil K, Witt R, Standridge S, Nues P, Lane J, Dinkel T, Coenraads M, von Hehn J, Jones M, Hale K, Suter B, Glaze D, Neul J, Percy A, Benke T. Consensus guidelines on managing Rett syndrome across the lifespan. BMJ Paediatr Open 2020; 4:e000717. [PMID: 32984552 PMCID: PMC7488790 DOI: 10.1136/bmjpo-2020-000717] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/19/2020] [Accepted: 07/21/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Rett syndrome (RTT) is a severe neurodevelopmental disorder with complex medical comorbidities extending beyond the nervous system requiring the attention of health professionals. There is no peer-reviewed, consensus-based therapeutic guidance to care in RTT. The objective was to provide consensus on guidance of best practice for addressing these concerns. METHODS Informed by the literature and using a modified Delphi approach, a consensus process was used to develop guidance for care in RTT by health professionals. RESULTS Typical RTT presents early in childhood in a clinically recognisable fashion. Multisystem comorbidities evolve throughout the lifespan requiring coordination of care between primary care and often multiple subspecialty providers. To assist health professionals and families in seeking best practice, a checklist and detailed references for guidance were developed by consensus. CONCLUSIONS The overall multisystem issues of RTT require primary care providers and other health professionals to manage complex medical comorbidities within the context of the whole individual and family. Given the median life expectancy well into the sixth decade, guidance is provided to health professionals to achieve current best possible outcomes for these special-needs individuals.
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Affiliation(s)
- Cary Fu
- Pediatrics and Neurology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Dallas Armstrong
- Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Eric Marsh
- Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - David Lieberman
- Neurology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Kathleen Motil
- Pediatrics, Baylor College of Medicine, Houston, Texas, USA.,Children's Nutrition Research Center, USDA ARS, Houston, Texas, USA
| | - Rochelle Witt
- Neurology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Shannon Standridge
- Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Paige Nues
- International Rett Syndrome Foundation, Cincinnati, Ohio, USA
| | - Jane Lane
- Civitan International Research Center, The University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, USA
| | - Tristen Dinkel
- Neurology, Children's Hospital Colorado, Aurora, Colorado, USA
| | | | - Jana von Hehn
- Rett Syndrome Research Trust, New York, New York, USA
| | - Mary Jones
- Pediatric Medicine, UCSF Benioff Children's Hospital Oakland, Oakland, California, USA
| | - Katie Hale
- Pediatric Medicine, UCSF Benioff Children's Hospital Oakland, Oakland, California, USA
| | - Bernhard Suter
- Pediatrics and Neurology, Baylor College of Medicine, Houston, Texas, USA.,Neurology, Texas Children's Hospital, Houston, Texas, USA
| | - Daniel Glaze
- Pediatrics and Neurology, Baylor College of Medicine, Houston, Texas, USA.,Neurology, Texas Children's Hospital, Houston, Texas, USA
| | - Jeffrey Neul
- Vanderbilt Kennedy Center, Nashville, Tennessee, USA.,Pediatrics, Pharmacology, and Special Education, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Alan Percy
- Pediatrics, Neurology, Neurobiology, Genetics, and Psychology, The University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, USA
| | - Timothy Benke
- Neurology, Children's Hospital Colorado, Aurora, Colorado, USA.,Pediatrics, Pharmacology, Neurology, Otolaryngology, University of Colorado Denver School of Medicine, Aurora, Colorado, USA
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4
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Wiedemann A, Renard E, Hernandez M, Dousset B, Brezin F, Lambert L, Weryha G, Feillet F. Annual Injection of Zoledronic Acid Improves Bone Status in Children with Cerebral Palsy and Rett Syndrome. Calcif Tissue Int 2019; 104:355-363. [PMID: 30554334 DOI: 10.1007/s00223-018-0505-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Accepted: 12/07/2018] [Indexed: 12/27/2022]
Abstract
Osteoporosis is a common complication of cerebral palsy and Rett's syndrome. It is responsible for multiple fractures, bone pain, and impaired quality of life. In case of Rett's syndrome, a specific dysfunction of osteoblasts causes bone fragility. We observed the effects of annual zoledronic acid (ZA) infusion in a cohort of children with cerebral palsy and Rett's syndrome. 27 children under 18 years (19 with cerebral palsy and 8 girls with Rett syndrome confirmed by MCEP2 mutation) were treated with an annual injection of 0.1 mg/kg (max 4 mg) of ZA. Calcium and vitamin D were combined in all patients from the first injection of ZA. Dental examination was performed before treatment. Data were analyzed retrospectively. Bone mineral density was measured at diagnosis and yearly thereafter. Bone mass density (BMD) is decreased in patient with cerebral palsy and RS. One year after injection of ZA, we observe an increase of Lumbar spine BMD from - 2.99 to - 2.14 SD (p < 0.0001) and femoral BMD from - 4.26 to - 3.32 SD (p < 0.001) In the subgroup of patient with Rett syndrome, we also observe an increase from - 3.27 to 2.50 SD (p = 0.018) of Lumbar spine BMD. No fractures have been observed in our cohort since the first infusion. Side effects (flu-like syndrome and hypocalcemia) were more common in younger patients and after the first infusion. No serious complications were noticed. This study confirms the efficacy and the safety of an annual injection of ZA to improve bone status in children with cerebral palsy and Rett syndrome. No severe adverse effects were observed.
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Affiliation(s)
- Arnaud Wiedemann
- Centre de référence des erreurs innées du métabolisme, Hôpital d'Enfants, CHRU Nancy, Nancy, France.
- Réanimation pédiatrique spécialisée, Hôpital d'enfants, CHRU Nancy, Nancy, France.
- Faculté de médecine, INSERM U-1256, Vandoeuvre les Nancy, France.
| | - Emeline Renard
- Service de Médecine Infantile, Hôpital d'enfants, CHRU Nancy, Nancy, France
- Faculté de médecine, INSERM U-1256, Vandoeuvre les Nancy, France
| | | | | | - François Brezin
- Service de Médecine Infantile, Hôpital d'enfants, CHRU Nancy, Nancy, France
| | | | | | - François Feillet
- Centre de référence des erreurs innées du métabolisme, Hôpital d'Enfants, CHRU Nancy, Nancy, France
- Service de Médecine Infantile, Hôpital d'enfants, CHRU Nancy, Nancy, France
- Faculté de médecine, INSERM U-1256, Vandoeuvre les Nancy, France
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5
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Abstract
Elucidating the functions of a particular gene is paramount to the understanding of how its dysfunction contributes to disease. This is especially important when the gene is implicated in multiple different disorders. One such gene is methyl-CpG-binding protein 2 (MECP2), which has been most prominently associated with the neurodevelopmental disorder Rett syndrome, as well as major neuropsychiatric disorders such as autism and schizophrenia. Being initially identified as a transcriptional regulator that modulates gene expression and subsequently also shown to be involved in other molecular events, dysfunction of the MeCP2 protein has the potential to affect many cellular processes. In this chapter, we will briefly review the functions of the MeCP2 protein and how its mutations are implicated in Rett syndrome and other neuropsychiatric disorders. We will further discuss about the mouse models that have been generated to specifically dissect the function of MeCP2 in different cell types and brain regions. It is envisioned that such thorough and targeted examination of MeCP2 functions can aid in enlightening the role that it plays in normal and dysfunctional physiological systems.
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Affiliation(s)
- Eunice W M Chin
- Neuroscience and Mental Health Faculty, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Eyleen L K Goh
- Neuroscience and Mental Health Faculty, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
- Department of Research, National Neuroscience Institute, Singapore, Singapore.
- Neuroscience Academic Clinical Programme, Singhealth Duke-NUS Academic Medical Center, Singapore, Singapore.
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6
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Lai YYL, Wong K, King NM, Downs J, Leonard H. Oral health experiences of individuals with Rett syndrome: a retrospective study. BMC Oral Health 2018; 18:195. [PMID: 30497449 PMCID: PMC6267076 DOI: 10.1186/s12903-018-0651-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Accepted: 10/23/2018] [Indexed: 12/24/2022] Open
Abstract
Background There is relatively little literature on the oral health experiences of individuals with Rett syndrome. This study described the incidence of dental extractions and restorations in a population-based cohort, according to a range of demographic and clinical factors. The association between bruxism and age was also investigated. Methods Existing questionnaire data in the population-based Australian Rett Syndrome Database for the years 2004, 2006, 2009 or 2011 on genetically confirmed female cases (n = 242) were analysed. Results The incidence rate of restorations and extractions were 6.8 per 100 person years (py) and 9.3 per 100 py respectively. The incidence of extractions decreased with increasing levels of income. Compared to those with a C-terminal mutation, the incidence rate of extraction was higher for those with large deletions (Incidence Rate Ratio (IRR) 4.93; 95% CI 1.46–16.7, p = 0.01). There was a 5% decrease in the risk of frequent bruxism for every one-year increase in age (Risk Ratio 0.95; 95% CI 0.94–0.97). Conclusions Social advantage may provide some protection for dental health in individuals with Rett syndrome. Those with more severe genotypes seemed to have poorer oral health outcomes.
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Affiliation(s)
- Y Y L Lai
- Department of Paediatric Dentistry, School of Dentistry, The University of Western Australia, Perth, WA, Australia.,Telethon Kids Institute, The University of Western Australia, Perth, WA, Australia
| | - K Wong
- Telethon Kids Institute, The University of Western Australia, Perth, WA, Australia
| | - N M King
- Department of Paediatric Dentistry, School of Dentistry, The University of Western Australia, Perth, WA, Australia
| | - J Downs
- Telethon Kids Institute, The University of Western Australia, Perth, WA, Australia.,School of Physiotherapy and Exercise Science, Curtin University, Perth, Australia
| | - H Leonard
- Telethon Kids Institute, The University of Western Australia, Perth, WA, Australia.
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7
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Kondo MA, Gray LJ, Pelka GJ, Leang SK, Christodoulou J, Tam PPL, Hannan AJ. Affective dysfunction in a mouse model of Rett syndrome: Therapeutic effects of environmental stimulation and physical activity. Dev Neurobiol 2015; 76:209-24. [DOI: 10.1002/dneu.22308] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 03/24/2015] [Accepted: 05/22/2015] [Indexed: 01/06/2023]
Affiliation(s)
- Mari A. Kondo
- Florey Institute of Neuroscience and Mental Health; University of Melbourne; Parkville Victoria 3010 Australia
- Department of Anatomy and Neuroscience; University of Melbourne; Parkville Victoria 3010 Australia
| | - Laura J. Gray
- Florey Institute of Neuroscience and Mental Health; University of Melbourne; Parkville Victoria 3010 Australia
| | - Gregory J. Pelka
- Embryology Unit; Children's Medical Research Institute; Westmead New South Wales 2145 Australia
| | - Sook-Kwan Leang
- Florey Institute of Neuroscience and Mental Health; University of Melbourne; Parkville Victoria 3010 Australia
| | - John Christodoulou
- Western Sydney Genetics Program; Children's Hospital at Westmead; Westmead, New South Wales 2145 Australia
- Disciplines of Paediatrics and Child Health and Genetic Medicine; University of Sydney; Sydney New South Wales 2006 Australia
| | - Patrick P. L. Tam
- Embryology Unit; Children's Medical Research Institute; Westmead New South Wales 2145 Australia
- Sydney Medical School; University of Sydney; Sydney New South Wales 2006 Australia
| | - Anthony J. Hannan
- Florey Institute of Neuroscience and Mental Health; University of Melbourne; Parkville Victoria 3010 Australia
- Department of Anatomy and Neuroscience; University of Melbourne; Parkville Victoria 3010 Australia
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8
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Kamal B, Russell D, Payne A, Constante D, Tanner KE, Isaksson H, Mathavan N, Cobb SR. Biomechanical properties of bone in a mouse model of Rett syndrome. Bone 2015; 71:106-14. [PMID: 25445449 PMCID: PMC4289916 DOI: 10.1016/j.bone.2014.10.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 10/09/2014] [Accepted: 10/15/2014] [Indexed: 12/22/2022]
Abstract
Rett syndrome (RTT) is an X-linked genetic disorder and a major cause of intellectual disability in girls. Mutations in the methyl-CpG binding protein 2 (MECP2) gene are the primary cause of the disorder. Despite the dominant neurological phenotypes, MECP2 is expressed ubiquitously throughout the body and a number of peripheral phenotypes such as scoliosis, reduced bone mineral density and skeletal fractures are also common and important clinical features of the disorder. In order to explore whether MeCP2 protein deficiency results in altered structural and functional properties of bone and to test the potential reversibility of any defects, we have conducted a series of histological, imaging and biomechanical tests of bone in a functional knockout mouse model of RTT. Both hemizygous Mecp2(stop/y) male mice in which Mecp2 is silenced in all cells and female Mecp2(stop/+) mice in which Mecp2 is silenced in ~50% of cells as a consequence of random X-chromosome inactivation, revealed significant reductions in cortical bone stiffness, microhardness and tensile modulus. Microstructural analysis also revealed alterations in both cortical and cancellous femoral bone between wild-type and MeCP2-deficient mice. Furthermore, unsilencing of Mecp2 in adult mice cre-mediated stop cassette deletion resulted in a restoration of biomechanical properties (stiffness, microhardness) towards wild-type levels. These results show that MeCP2-deficiency results in overt, but potentially reversible, alterations in the biomechanical integrity of bone and highlights the importance of targeting skeletal phenotypes in considering the development of pharmacological and gene-based therapies.
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Affiliation(s)
- Bushra Kamal
- Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, UK; Laboratory of Human Anatomy, School of Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK; Department of Anatomy, Khyber Medical University, Khyber Pakhtunkhwa, Pakistan
| | - David Russell
- Laboratory of Human Anatomy, School of Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Anthony Payne
- Laboratory of Human Anatomy, School of Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Diogo Constante
- School of Engineering, University of Glasgow, Glasgow G12 8QQ, UK; Faculadade de Engenharia da Universidade do Porto, Porto, Portugal
| | - K Elizabeth Tanner
- School of Engineering, University of Glasgow, Glasgow G12 8QQ, UK; Department of Orthopaedics, Clinical Sciences, Lund University, Lund, S-22185, Sweden
| | - Hanna Isaksson
- Department of Biomedical Engineering, Lund University, Lund, Sweden
| | - Neashan Mathavan
- Department of Biomedical Engineering, Lund University, Lund, Sweden
| | - Stuart R Cobb
- Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, UK.
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9
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Motil KJ, Barrish JO, Neul JL, Glaze DG. Low bone mineral mass is associated with decreased bone formation and diet in girls with Rett syndrome. J Pediatr Gastroenterol Nutr 2014; 59:386-92. [PMID: 25144778 PMCID: PMC4144049 DOI: 10.1097/mpg.0000000000000440] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVE The aim of the present study was to characterize biomarkers of bone turnover and their relation with bone mineral mass in a cross-sectional cohort of girls with Rett syndrome (RTT) and to examine the role of dietary, biochemical, hormonal, and inflammatory factors on bone mineral mass and bone biomarkers in this disorder. METHODS Total body bone mineral content (BMC) and bone mineral density (BMD) were determined by dual-energy x-ray absorptiometry. Dietary nutrient intakes were determined from 3-day food records. Biomarkers of bone turnover, bone metabolites, vitamin D metabolites, hormones, and inflammatory markers were measured by standard clinical laboratory methods. RESULTS Serum osteocalcin, bone alkaline phosphatase, and C-telopeptide showed significant inverse relations with age in the RTT cohort. Mean osteocalcin concentrations were significantly lower and mean bone alkaline phosphatase concentrations were significantly higher for individual age groups in the RTT cohort than mean values for their respective age ranges in the reference population. Significant inverse associations were identified between urinary calcium losses, expressed as calcium:creatinine ratios, and total body BMC and BMD z scores. Dietary protein, calcium, and phosphorus intakes, expressed as a proportion of Dietary Reference Intakes for age and sex, showed significant positive associations with total body BMD z scores. CONCLUSIONS The present study suggests decreased bone formation instead of increased bone resorption may explain in part the deficits in bone mineral mass in RTT and that attention to the adequacy of dietary protein, calcium, and phosphorus intakes may offer an opportunity to improve bone health in RTT.
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Affiliation(s)
- Kathleen J. Motil
- USDA/ARS Children's Nutrition Research Center, Houston, TX 77030
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030
| | - Judy O. Barrish
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030
- The Blue Bird Circle Rett Center, Houston, TX 77030
| | - Jeffrey L. Neul
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030
- The Blue Bird Circle Rett Center, Houston, TX 77030
| | - Daniel G. Glaze
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030
- The Blue Bird Circle Rett Center, Houston, TX 77030
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10
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Roende G, Petersen J, Ravn K, Fuglsang K, Andersen H, Nielsen JB, Brøndum-Nielsen K, Jensen JEB. Low bone turnover phenotype in Rett syndrome: results of biochemical bone marker analysis. Pediatr Res 2014; 75:551-8. [PMID: 24375084 DOI: 10.1038/pr.2013.252] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 09/19/2013] [Indexed: 11/09/2022]
Abstract
BACKGROUND Patients with Rett syndrome (RTT) are at risk of having low bone mass and low-energy fractures. METHODS We characterized bone metabolism by both bone formation and resorption markers in blood in a RTT population of 61 girls and women and 122 well-matched healthy controls. Levels of N-terminal propeptides of collagen type 1 (P1NP), C-terminal telopeptide cross links (CTX), osteocalcin (OC), and bone-specific alkaline phosphatase (B-ALP) were compared between RTT patients and controls in regression models adjusted for BMI, vitamin D status, volumetric bone mineral apparent density of the lumbar spine (vBMAD spine), and femoral neck (vBMAD neck). We examined biochemical bone marker levels overall and stratified to persons younger than age 25 y or equal to or older than age 25 y. RESULTS The RTT patients had reduced levels of all biochemical bone markers (P < 0.05), which remained significant in persons younger than 25 y (P ≤ 0.001) regarding P1NP, CTX, and OC. Bone marker levels were not significantly associated to methyl-CpG-binding protein 2 (MECP2) mutation group, walking ability, or previous low-energy fractures. CONCLUSION Our findings of a low bone turnover state in girls with RTT suggest critical attention to medical treatment of low bone mass in young RTT patients.
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Affiliation(s)
- Gitte Roende
- Center for Rett Syndrome, Kennedy Center, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
| | - Janne Petersen
- Clinical Research Centre, Copenhagen University Hospital, Hvidovre Hospital, Hvidovre, Denmark
| | - Kirstine Ravn
- Center for Rett Syndrome, Kennedy Center, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
| | - Kathrine Fuglsang
- Center for Rett Syndrome, Kennedy Center, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
| | - Henrik Andersen
- Department of Exercise and Sports Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jytte B Nielsen
- Center for Rett Syndrome, Kennedy Center, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
| | - Karen Brøndum-Nielsen
- Genetic Counseling Clinic, Kennedy Center, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
| | - Jens-Erik B Jensen
- Department of Endocrinology, Copenhagen University Hospital, Hvidovre Hospital, Hvidovre, Denmark
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11
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Lotan M, Reves-Siesel R, Eliav-Shalev RS, Merrick J. Osteoporosis in Rett syndrome: a case study presenting a novel management intervention for severe osteoporosis. Osteoporos Int 2013; 24:3059-63. [PMID: 23828127 DOI: 10.1007/s00198-013-2423-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Accepted: 05/31/2013] [Indexed: 10/26/2022]
Abstract
The present article describes a successful novel therapeutic intervention with Aredia with one child with Rett syndrome, after suffering from six pathological fractures within less than 3 years due to severe osteoporosis. Since the initiation of the treatment (3 years ago), the child has not suffered any fractures. Patients with chronic diseases and those with disabilities or on anticonvulsant medications are at risk for low bone density and possibly for the resultant pathologic fractures that define osteoporosis in children. Individuals with Rett syndrome (RS) have been shown to have low bone mineral density (or osteopenia) at a young age. If osteoporosis occurs in a girl with RS, it can inflict pain and seriously impair the child's mobility and quality of life. The present article describes a case study of a child with RS (showing an average of 1.75 fractures annually for the 4 years preceding the treatment) before and after a treatment with Aredia. Patient received 30 mg/day for 3 days on a once every 3-month cycle. There was a 45 % improvement in bone mass density (BMD) values from pre-post-intervention. The child had no fractures in the 3 years posttreatment. This finding is significant (p < 0.03). The BMD Z-scores of the child showed severe osteoporosis (Z-score of -3.8) at pre-intervention and are elevated to osteopenia levels (Z-score of -1.3) at post-intervention measurements. All measurements suggest that the treatment successfully reversed the osteoporotic process and prevented further fractures. This change caused great relief to the child and her family and an improvement in their quality of life. The findings support the ability (in one case) to reverse the progression of osteoporosis in individuals with Rett syndrome showing severe osteoporosis with multiple fractures.
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Affiliation(s)
- M Lotan
- Israeli Rett Center, National Rett Syndrome Evaluation Team, Chaim Sheba Medical Center, Tel HaShomer, Ramat Gan, Israel,
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Motil KJ, Caeg E, Barrish JO, Geerts S, Lane JB, Percy AK, Annese F, McNair L, Skinner SA, Lee HS, Neul JL, Glaze DG. Gastrointestinal and nutritional problems occur frequently throughout life in girls and women with Rett syndrome. J Pediatr Gastroenterol Nutr 2012; 55:292-8. [PMID: 22331013 PMCID: PMC3393805 DOI: 10.1097/mpg.0b013e31824b6159] [Citation(s) in RCA: 128] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
OBJECTIVE We conducted a nationwide survey to determine the prevalence of common gastrointestinal and nutritional disorders in Rett syndrome (RTT) based on parental reporting and related the occurrence of these problems to age and methyl-CpG-binding protein 2 (MECP2) gene status. METHODS We designed a questionnaire that probed symptoms, diagnoses, diagnostic tests, and treatment interventions related to gastrointestinal and nutritional problems in RTT. The International Rett Syndrome Foundation distributed the questionnaire to 1666 family-based members and forwarded their responses for our review. We interrogated the Rare Disease Clinical Research Network database to supplement findings related to medications used to treat gastrointestinal problems in RTT. RESULTS Parents of 983 female patients with RTT (59%) responded and identified symptoms and diagnoses associated with gastrointestinal dysmotility (92%), chewing and swallowing difficulties (81%), weight deficits or excess (47%), growth deficits (45%), low bone mineral content or fractures (37%), and biliary tract disorders (3%). Height-for-age, weight-for-age, and body mass index z scores decreased significantly with age; height- and weight-, but not body mass index-for-age z scores were significantly lower in female subjects with MECP2 mutations than in those without. Vomiting, nighttime awakening, gastroesophageal reflux, chewing difficulty, and choking with feeding were significantly less likely to occur with increasing age. Short stature, low bone mineral content, fractures, and gastrostomy placement were significantly more likely to occur with increasing age. Chewing difficulty, choking with feeding, and nighttime awakening were significantly less likely to occur, whereas short stature was significantly more likely to occur, in female subjects with MECP2 mutations than in those without. Diagnostic evaluations and therapeutic interventions were used less frequently than the occurrence of symptoms or diagnoses in the RTT cohort. CONCLUSIONS Gastrointestinal and nutritional problems perceived by parents are prevalent throughout life in girls and women with RTT and may pose a substantial medical burden for their caregivers. Physician awareness of these features of RTT may improve the health and quality of life of individuals affected with this disorder.
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Affiliation(s)
- Kathleen J Motil
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA.
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Caffarelli C, Gonnelli S, Tanzilli L, Hayek J, Vichi V, Franci MB, Lucani B, Nuti R. The relationship between serum ghrelin and body composition with bone mineral density and QUS parameters in subjects with Rett syndrome. Bone 2012; 50:830-5. [PMID: 22306927 DOI: 10.1016/j.bone.2012.01.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 01/16/2012] [Accepted: 01/20/2012] [Indexed: 10/14/2022]
Abstract
Several studies have reported that females with Rett's syndrome frequently have marked decreases in bone mineral density (BMD). However, the pathogenesis of impaired bone status in RTT girls remains controversial. This study aimed to investigate whether ghrelin, an orexigenic peptide secreted by the stomach, was associated with body composition parameters, bone mineral density and quantitative ultrasound (QUS) in girls with Rett's syndrome. In 123 Rett girls (13.6±8.2 years) and in 55 similar age range controls we evaluated ghrelin serum levels, 25OHD, quantitative ultrasound parameters at phalanxes by Bone Profiler-IGEA (amplitude dependent speed of sound: AD-SoS and bone transmission time: BTT), total body bone mineral density (BMD-WB) by Hologic QDR 4500. Whole body mineral content (BMC-WB), BMC-WB/height, fat mass (FM), fat percentage and lean mass (LM) were determined by using the same DXA device. We found that serum ghrelin levels were significantly higher in the Rett patients with respect to the control group (p<0.05). In Rett girls ghrelin serum levels were inversely correlated with both age (R(2)=0.17, p<0.001) and BMI (R(2)=0.14, p<0.001). Moreover, in Rett subjects the values of BMD-WB, BMC-WB, BMC-WB/height and QUS parameters were significantly lower than in control subjects. Fat mass and lean mass were lower in Rett subjects than in controls, but the difference reached the statistical significance only for lean mass. In Rett girls ghrelin serum levels were not predictors of bone status. Instead, we found that in Rett subjects, lean mass, age and 25OHD were significant independent predictors of BMC-WB/h, whereas both age and height were independent predictors of BMD-WB. Moreover, AD-SoS was predicted by age, fat percentage and height; while BTT was predicted only by height. In conclusion, our findings indicate that ghrelin levels were higher in Rett girls with respect to healthy controls, and negatively associated with both DXA and QUS parameters. However, in our study ghrelin was not found to be an independent predictor of bone mass, so supporting the hypothesis that ghrelin is elevated in Rett subjects in a compensatory manner.
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Affiliation(s)
- C Caffarelli
- Department of Internal Medicine, Endocrine-Metabolic Science and Biochemistry, University of Siena, Italy.
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Abstract
OBJECTIVES The aim of the study was to determine the prevalence of vitamin D deficiency and identify the relation between 25-hydroxyvitamin D (25-(OH)D) levels and the consumption of dietary sources of vitamin D or exposure to anticonvulsants in girls and women with Rett syndrome (RTT). SUBJECTS AND METHODS Retrospective review of the medical records of 284 girls and women with RTT to determine serum 25-(OH)D and parathyroid hormone levels, nutritional status, dietary sources of vitamin D, exposure to anticonvulsants, degree of mobility, and MECP2 status. RESULTS Twenty percent of girls and women who were tested (n = 157) had 25-(OH)D levels <50 nmol/L. Multivitamin supplements, vitamin D-fortified milk, and commercial formulas were consumed by 40%, 52%, and 54%, respectively. Anticonvulsants were used by 57%, and 39% ambulated independently. Median 25-(OH)D levels were lower in individuals who did not receive multivitamin supplements (P < 0.05) or commercial formulas (P < 0.001) than in those who did. Median 25-(OH)D levels differed (P < 0.01) among racial and ethnic groups, but the number in some groups was small. Nutritional status, use of anticonvulsants, degree of mobility, and MECP2 status did not influence 25-(OH)D levels. CONCLUSIONS Vitamin D deficiency is prevalent in girls and women with RTT. The use of multivitamin supplements or commercial formulas is associated with improved vitamin D levels. Attention to vitamin D may enhance bone mineral deposition and reduce the frequency of bone fractures in these individuals.
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Roende G, Ravn K, Fuglsang K, Andersen H, Nielsen JB, Brøndum-Nielsen K, Jensen JEB. DXA measurements in Rett syndrome reveal small bones with low bone mass. J Bone Miner Res 2011; 26:2280-6. [PMID: 21590733 DOI: 10.1002/jbmr.423] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Low bone mass is reported in growth-retarded patients harboring mutations in the X-linked methyl-CpG-binding protein 2 (MECP2) gene causing Rett syndrome (RTT). We present the first study addressing both bone mineral density (BMD) and bone size in RTT. Our object was to determine whether patients with RTT do have low BMD when correcting for smaller bones by examination with dual-energy X-ray absorptiometry (DXA). We compared areal BMD (aBMD(spine) and aBMD(total hip) ) and volumetric bone mineral apparent density (vBMAD(spine) and vBMAD(neck) ) in 61 patients and 122 matched healthy controls. Further, spine and hip aBMD and vBMAD of patients were associated with clinical risk factors of low BMD, low-energy fractures, MECP2 mutation groups, and X chromosome inactivation (XCI). Patients with RTT had reduced bone size on the order of 10% and showed lower values of spine and hip aBMD and vBMAD (p < .001) adjusted for age, pubertal status, and body mass index (BMI). aBMD(spine) , vBMAD(spine) , and aBMD(total hip) were associated with low-energy fractures (p < .05). Walking was significantly associated to aBMD(total hip) and vBMAD(neck) adjusted for age and body mass index (BMI). Further, vBMAD(neck) was significantly associated to a diagnosis of epilepsy, antiepileptic treatment, and MECP2 mutation group, but none of the associations with vBMAD(neck) remained clinically significant in a multiple adjusted model including age and BMI. Neither aBMD(spine) , vBMAD(spine) , nor aBMD(total hip) were significantly associated with epilepsy, antiepileptic treatment, MECP2 mutation group, XCI, or vitamin D status. Low bone mass and small bones are evident in RTT, indicating an apparent low-bone-formation phenotype.
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Affiliation(s)
- Gitte Roende
- Center for Rett Syndrome, Kennedy Center, Glostrup, Denmark.
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16
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Jefferson AL, Woodhead HJ, Fyfe S, Briody J, Bebbington A, Strauss BJ, Jacoby P, Leonard H. Bone mineral content and density in Rett syndrome and their contributing factors. Pediatr Res 2011; 69:293-8. [PMID: 21178825 PMCID: PMC3906210 DOI: 10.1203/pdr.0b013e31820b937d] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This study used densitometry to investigate the areal bone mineral density (aBMD) and bone mineral content (BMC) in an Australian Rett syndrome cohort and to assess how factors such as genotype, epilepsy, BMI, and mobility affect these parameters. The influence of lean tissue mass (LTM) and bone area (BA) on total body BMC (TBBMC) was also investigated. Participants, recruited from the Australian Rett Syndrome Database (ARSD), had TBBMC and lumbar spine (LS) and femoral neck (FN) aBMD measured using Dual energy x-ray absorptiometry. Mean height standardized Z scores and CIs for the bone outcomes were obtained from multiple regression models. The mean height Z score for the FN aBMD was low at -2.20, while the LS aBMD was -0.72. The TBBMC mean height Z score was -0.62, although once adjusted for BA and LTM, the mean was above zero, suggesting that low BMC can be explained by narrow bones and decreased muscle mass, likely secondary to decreased mobility. Multiple linear regression identified the p.R168× and p.T158M mutations as the strongest predictors of low aBMC and BMD for all bone outcomes. The strong relationship between genotype, BMC, and aBMD is likely underpinned by the strong relationship between LTM, mobility, and bone outcome measures.
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Affiliation(s)
- Amanda L Jefferson
- School of Biomedical Sciences, Curtin University of Technology, Perth, Western Australia 6845, Australia
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17
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Roende G, Ravn K, Fuglsang K, Andersen H, Vestergaard A, Brøndum-Nielsen K, Jensen JEB, Nielsen JB. Patients with Rett syndrome sustain low-energy fractures. Pediatr Res 2011; 69:359-64. [PMID: 21178819 DOI: 10.1203/pdr.0b013e31820bc6d3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We present the first case-control study addressing both fracture occurrence and fracture mechanisms in Rett syndrome (RTT). Two previous studies have shown increased fracture risk in RTT. This was also our hypothesis regarding the Danish RTT population. Therefore, we investigated risk factors associated with low-energy trauma and the association to methyl-CpG-binding protein 2 (MECP2) mutations. A total of 61 female patients with RTT and 122 healthy controls matched according to age and pubertal/menopause status were examined by questionnaires, bone biochemical markers in blood, and clinical and x-ray evaluations. National register search on fracture diagnoses was done to obtain complete fracture histories. Our results showed that patients with RTT sustained significantly more low-energy fractures from early age compared with controls, even though overall fracture occurrence apparently was not increased. Low-energy fractures were significantly associated with less mobility and lack of ambulation. Associations with MECP2 mutations or epilepsy were not demonstrated, contrary to previous findings. Blood biochemistry indicated a possible need for D vitamin supplementation in RTT. Our study casts light on fracture occurrence in RTT and points to a need for future research in bone development and fracture risk to establish directions for improved prevention and treatment of low-energy fractures in RTT.
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Affiliation(s)
- Gitte Roende
- Center for Rett Syndrome, Kennedy Center, Glostrup 2600, Denmark.
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18
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Hofstaetter JG, Roetzer KM, Krepler P, Nawrot-Wawrzyniak K, Schwarzbraun T, Klaushofer K, Roschger P. Altered bone matrix mineralization in a patient with Rett syndrome. Bone 2010; 47:701-5. [PMID: 20601296 DOI: 10.1016/j.bone.2010.06.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Revised: 05/31/2010] [Accepted: 06/09/2010] [Indexed: 10/19/2022]
Abstract
Rett syndrome (RTT) is a common X-linked neurodevelopmental disorder caused by mutations in the coding region of methyl-CpG-binding 2 (MECP2) gene. Patients with RTT have a low bone mineral density and increased risk of fracture. However, very little is known if bone matrix mineralization is altered in RTT. A 17-year-old girl with a classical form of RTT with a heterozygous nonsense mutation in exon 3 in the MECP2-gene was treated in our hospital. Her femoral neck BMD is 43.3% below the 3rd percentile when compared to age and sex-matched controls. She underwent surgery for correction of her scoliosis, which provided a unique opportunity to obtain bone tissue to study bone matrix mineralization (Bone Mineralization Density Distribution-BMDD) using quantitative backscattered electron imaging (qBEI) and histomorphometry. BMDD outcomes were compared to recently published normative reference data for young individuals. qBEI analysis showed a significant shift to lower matrix mineralization despite histomorphometric indices indicate a low bone turnover. There was a reduction in CaMean (-7.92%) and CaPeak (-3.97%), which describe the degree of mineralization. Furthermore the fraction of low mineralized matrix (CaLow: +261.84%) was dramatically increased, which was accompanied with an increase in the heterogeneity of mineralization (CaWidth: +86.34%). Our findings show a significantly altered bone matrix mineralization of a typical patient with RTT. This may partly explain the low bone density seen in these patients. These results also warrant further studies on the molecular role of MECP2 in bone matrix mineralization.
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Affiliation(s)
- Jochen G Hofstaetter
- Department of Orthopaedic Surgery, Vienna General Hospital, Medical University of Vienna, Vienna, Austria.
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19
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Prior C, Nunes A, Rios M, Sequeiros J, Maciel P, Gomes L, Temudo T. Trastornos nutricionales y gastrointestinales en el síndrome de Rett: importancia de la intervención temprana. An Pediatr (Barc) 2010; 72:191-8. [DOI: 10.1016/j.anpedi.2009.02.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2008] [Revised: 01/22/2009] [Accepted: 02/03/2009] [Indexed: 12/11/2022] Open
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20
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O'Connor RD, Zayzafoon M, Farach-Carson MC, Schanen NC. Mecp2 deficiency decreases bone formation and reduces bone volume in a rodent model of Rett syndrome. Bone 2009; 45:346-56. [PMID: 19414073 PMCID: PMC2739100 DOI: 10.1016/j.bone.2009.04.251] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Revised: 03/25/2009] [Accepted: 04/24/2009] [Indexed: 01/03/2023]
Abstract
Rett syndrome (RTT), a neurological disorder characterized by neurological impairment and a high frequency of osteopenia which often manifests early in childhood, most often is caused by inactivating mutations in the X-linked gene encoding a regulator of epigenetic gene expression, methyl CpG binding protein, MeCP2. Clinical data show that, along with neurological defects, females with RTT frequently have marked decreases in bone mineral density (BMD) beyond that expected from disuse atrophy. To investigate the relationship between loss of Mecp2 and reduced BMD, we used a Mecp2 null mouse model, Mecp2 (-/yBIRD), for our histological and biochemical studies. Mecp2 (-/yBIRD) mice have significantly shorter femurs and an overall reduced skeletal size compared to wild-type mice by post-natal day 60 (P60). Histological and histomorphometric studies identified growth plate abnormalities as well as decreased cortical and trabecular bone in P21 and especially in P60 Mecp2 (-/yBIRD) mice. Dynamic histomorphometry revealed decreased mineral apposition rates (MAR) in Mecp2 null femoral trabecular bone as well as in calvarial bone samples. While changes in MAR of cortical bone were not significant, loss of Mecp2 significantly reduced cortical, trabecular and calvarial bone volume compared with age-matched wild-type animals. These differences indicate that Mecp2 deficiency leads to osteoblast dysfunction, which translates into reduced osteoid deposition accounting for the reduced bone volume phenotype. While individual variations were observed in OPG and Rankl concentrations, molar ratios of OPG:Rankl at P21 and P60 were comparable between wild-type and Mecp2 (-/yBIRD) mice and showed a consistent excess of OPG. In tibial sections, TRAP staining demonstrated equivalent osteoclast number per bone surface measurements between wild-type and null animals. Our work with a Mecp2 null mouse model suggests epigenetic regulation of bone in the Mecp2 (-/yBIRD) mice which is associated with decreased osteoblast activity rather than increased osteoclastic bone loss.
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Affiliation(s)
- R D O'Connor
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
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21
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Fyffe SL, Neul JL, Samaco RC, Chao HT, Ben-Shachar S, Moretti P, McGill BE, Goulding EH, Sullivan E, Tecott LH, Zoghbi HY. Deletion of Mecp2 in Sim1-expressing neurons reveals a critical role for MeCP2 in feeding behavior, aggression, and the response to stress. Neuron 2008; 59:947-58. [PMID: 18817733 PMCID: PMC2597031 DOI: 10.1016/j.neuron.2008.07.030] [Citation(s) in RCA: 194] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 06/05/2008] [Accepted: 07/21/2008] [Indexed: 11/17/2022]
Abstract
Rett Syndrome (RTT) is an autism spectrum disorder caused by mutations in the X-linked gene encoding methyl-CpG binding protein 2 (MeCP2). In order to map the neuroanatomic origins of the complex neuropsychiatric behaviors observed in patients with RTT and to uncover endogenous functions of MeCP2 in the hypothalamus, we removed Mecp2 from Sim1-expressing neurons in the hypothalamus using Cre-loxP technology. Loss of MeCP2 in Sim1-expressing neurons resulted in mice that recapitulated the abnormal physiological stress response that is seen upon MeCP2 dysfunction in the entire brain. Surprisingly, we also uncovered a role for MeCP2 in the regulation of social and feeding behaviors since the Mecp2 conditional knockout (CKO) mice were aggressive, hyperphagic, and obese. This study demonstrates that deleting Mecp2 in a defined brain region is an excellent approach to map the neuronal origins of complex behaviors and provides new insight about the function of MeCP2 in specific neurons.
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Affiliation(s)
- Sharyl L Fyffe
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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22
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Motil KJ, Ellis KJ, Barrish JO, Caeg E, Glaze DG. Bone mineral content and bone mineral density are lower in older than in younger females with Rett syndrome. Pediatr Res 2008; 64:435-9. [PMID: 18535484 PMCID: PMC2663405 DOI: 10.1203/pdr.0b013e318180ebcd] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Although bone mineral deficits have been identified in Rett syndrome (RTT), the prevalence of low bone mineral density (BMD) and its association with skeletal fractures and scoliosis has not been characterized fully in girls and women with RTT. Accordingly, we measured total body bone mineral content (BMC) and BMD using dual energy x-ray absorptiometry in a cross-sectional group of 50 females, aged 2-38 y, with RTT. Methyl-CpG-binding 2 (MECP2) mutations, skeletal fractures, and scoliosis were documented. The prevalence of BMC and BMD z scores < or-2 SD was 59 and 45%, respectively. Although absolute BMC and BMD increased significantly with increasing age, BMC, and BMD z scores were significantly lower in older than in younger females. The prevalence of fractures and scoliosis was 28 and 64%, respectively. Low BMD z scores were positively associated with fractures and scoliosis. Deficits in BMD were identified across a broad range of MECP2 mutations. This study identified associations among low BMD, fractures, and scoliosis, and underscored the need for better understanding of the molecular mechanisms of MECP2 in the regulation of bone mineral metabolism.
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Affiliation(s)
- Kathleen J Motil
- USDA/ARS Children's Nutrition Research Center, Departments of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA.
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Abstract
Rett syndrome is a relatively rare neurodevelopmental disorder (incidence: approximately one out of 10,000 female births) that reached worldwide prominence in the early 1980s. Owing to its overwhelming predominance in females, Rett syndrome was regarded as a genetic disorder. However, its occurrence is sporadic, with a recurrence risk well below 0.5%. In 1999, confirmation was provided by the demonstration of mutations in the MECP2 gene. At present, more than 95% of females who fulfill consensus criteria for Rett syndrome have a mutation in this gene. Over the past 25 years, understanding of the clinical features and natural history of this unique neurodevelopmental disorder has evolved dramatically. However, large segments of healthcare professionals and the general public still remain relatively uninformed. This review details the clinical picture of Rett syndrome and the diagnostic strategies required, explores the critical medical issues and recent advances in molecular neurobiology, provides an overview of intervention strategies that have been developed to date and sets the stage for future treatment trials as novel, and potentially effective, pharmacologic or molecular interventions become available.
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Affiliation(s)
- Alan K Percy
- a 1530 3rd Avenue South, Civitan International Research Center, Birmingham, AL 35294, USA.
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Abstract
Recent progress in our understanding of Rett syndrome has been dramatic. Against the background that the clinical features of Rett syndrome may be reversible, in part or in whole, substantial optimism has emerged regarding possible therapies. As such, it is timely to update recent research progress. This update summarizes research advances during the past 18 to 24 months in terms of clinical and translational research, as well as basic research.
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Affiliation(s)
- Alan K Percy
- Department of Pediatrics, University of Alabama at Birmingham, AL 35294-0021, USA.
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Gonnelli S, Caffarelli C, Hayek J, Montagnani A, Cadirni A, Franci B, Lucani B, Rossi S, Nuti R. Bone ultrasonography at phalanxes in patients with Rett syndrome: a 3-year longitudinal study. Bone 2008; 42:737-42. [PMID: 18242156 DOI: 10.1016/j.bone.2007.12.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Revised: 11/21/2007] [Accepted: 12/11/2007] [Indexed: 01/24/2023]
Abstract
Osteopenia is a frequent and early complication of Rett syndrome. This study aimed to evaluate the usefulness of Quantitative Ultrasonography (QUS) at phalanxes in the assessment and monitoring of bone status in Rett patients. We studied 109 girls (10.1+/-6.1 years; range 3-25 years) and 101 age-matched controls. Serum calcium (Ca), bone alkaline phosphatase (B-ALP), parathyroid hormone (PTH), 25-hydroxyvitamin D (25OHD) and QUS parameters at phalanxes by Bone Profiler-IGEA (amplitude dependent speed of sound: AD-SoS and bone transmission time: BTT) were measured. At baseline both QUS parameters and 25OHD levels were significantly lower in Rett patients than in controls. Serum 25OHD was inversely correlated with serum PTH and BTT Z-score and BTT Z-score was significantly lower (p<0.05) in the girls with a 25OHD serum levels<or=9 ng/ml. Moreover, multiple regression analysis showed that BTT was significantly influenced by 25OHD levels. The design of the study was to carry out a twelve monthly evaluation of QUS and biochemical parameters for 3-years. 82 Rett patients completed the 36 month longitudinal study. During the study period in the patients, who at baseline were non ambulatory, BTT and AD-SoS Z-score presented the tendency to markedly decrease; in contrast, mild changes of the QUS parameters were observed in patients with severe or mild-moderate ambulatory impairment. Significant difference of BTT Z-score and AD-SoS Z-score among the 3 groups of patients categorized on the basis of ambulatory performance were observed at years 2 and 3. The AD-SoS Z-score at the end of the study period were significantly influenced by the changes in ambulatory performance and the use of anticonvulsant therapy. In conclusion our results suggest the usefulness of QUS parameters at phalanxes in the monitoring of bone status in Rett patients. Low levels of 25OHD and ambulatory impairment play a key role in the skeletal deterioration in Rett girls.
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Affiliation(s)
- S Gonnelli
- Department of Internal Medicine, Endocrine-Metabolic Science and Biochemistry, University of Siena, Policlinico Le Scotte, Viale Bracci 2, 53100 Siena, Italy.
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26
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Downs J, Bebbington A, Woodhead H, Jacoby P, Jian L, Jefferson A, Leonard H. Early determinants of fractures in Rett syndrome. Pediatrics 2008; 121:540-6. [PMID: 18310203 DOI: 10.1542/peds.2007-1641] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES The goals were to compare the fracture incidence in Rett syndrome with that in the general population and to investigate the impact of genotype, epilepsy, and early motor skills on subsequent fracture incidence in girls and young women with Rett syndrome. METHODS The Australian Rett syndrome study, a population-based study operating since 1993, investigated Australian subjects with Rett syndrome born since 1976. The 234 (81.2%) of 288 verified cases in the Australian Rett syndrome database in 2004 whose families had completed follow-up questionnaires and provided information about fracture history were included in the analyses. The main outcomes were fracture incidence in the Rett syndrome population and fracture risk according to genotype, presence of epilepsy, and early motor profile. RESULTS Fracture incidence in this cohort was 43.3 episodes per 1000 person-years, nearly 4 times greater than the population rate. Risk was increased specifically in cases with p.R270X mutations and in cases with p.R168X mutations. Having epilepsy also increased fracture risk, even after adjustment for genotype. CONCLUSIONS Girls and young women with Rett syndrome are at increased risk of fracture. Those with mutations found previously to be more severe and those with epilepsy have an increased propensity toward fractures. Improved understanding of the risk factors for fracture could contribute to better targeting of interventions to decrease fracture incidence in this vulnerable population.
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Affiliation(s)
- Jennepher Downs
- Centre for Child Health Research, University of Western Australia, Telethon Institute for Child Health Research, Perth, Western Australia, 6872
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27
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McGill BE, Bundle SF, Yaylaoglu MB, Carson JP, Thaller C, Zoghbi HY. Enhanced anxiety and stress-induced corticosterone release are associated with increased Crh expression in a mouse model of Rett syndrome. Proc Natl Acad Sci U S A 2006; 103:18267-72. [PMID: 17108082 PMCID: PMC1636379 DOI: 10.1073/pnas.0608702103] [Citation(s) in RCA: 182] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Rett syndrome (RTT), a postnatal neurodevelopmental disorder, is caused by mutations in the methyl-CpG-binding protein 2 (MECP2) gene. Children with RTT display cognitive and motor abnormalities as well as autistic features. We studied mice bearing a truncated Mecp2 allele (Mecp2(308/Y) mice) and found evidence of increased anxiety-like behavior and an abnormal stress response as evidenced by elevated serum corticosterone levels. We found increased corticotropin-releasing hormone (Crh) gene expression in the paraventricular nucleus of the hypothalamus, the central amygdala, and the bed nucleus of the stria terminalis. Finally, we discovered that MeCP2 binds the Crh promoter, which is enriched for methylated CpG dinucleotides. In contrast, the MeCP2(308) protein was not detected at the Crh promoter. This study identifies Crh as a target of MeCP2 and implicates Crh overexpression in the development of specific features of the Mecp2(308/Y) mouse, thereby providing opportunities for clinical investigation and therapeutic intervention in RTT.
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Affiliation(s)
- Bryan E. McGill
- *Department of Neuroscience
- Medical Scientist Training Program
| | | | | | - James P. Carson
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology
- National Center for Macromolecular Imaging
| | - Christina Thaller
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology
| | - Huda Y. Zoghbi
- *Department of Neuroscience
- Department of Molecular and Human Genetics
- Department of Neurology
- **Department of Pediatrics, and
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030
- To whom correspondence should be addressed. E-mail:
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