1
|
Merritt JK, Fang X, Caylor RC, Skinner SA, Friez MJ, Percy AK, Neul JL. Normalized Clinical Severity Scores Reveal a Correlation between X Chromosome Inactivation and Disease Severity in Rett Syndrome. Genes (Basel) 2024; 15:594. [PMID: 38790223 PMCID: PMC11120815 DOI: 10.3390/genes15050594] [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: 03/29/2024] [Revised: 05/01/2024] [Accepted: 05/05/2024] [Indexed: 05/26/2024] Open
Abstract
Rett Syndrome (RTT) is a severe neurodevelopmental disorder predominately diagnosed in females and primarily caused by pathogenic variants in the X-linked gene Methyl-CpG Binding Protein 2 (MECP2). Most often, the disease causing the MECP2 allele resides on the paternal X chromosome while a healthy copy is maintained on the maternal X chromosome with inactivation (XCI), resulting in mosaic expression of one allele in each cell. Preferential inactivation of the paternal X chromosome is theorized to result in reduced disease severity; however, establishing such a correlation is complicated by known MECP2 genotype effects and an age-dependent increase in severity. To mitigate these confounding factors, we developed an age- and genotype-normalized measure of RTT severity by modeling longitudinal data collected in the US Rett Syndrome Natural History Study. This model accurately reflected individual increase in severity with age and preserved group-level genotype specific differences in severity, allowing for the creation of a normalized clinical severity score. Applying this normalized score to a RTT XCI dataset revealed that XCI influence on disease severity depends on MECP2 genotype with a correlation between XCI and severity observed only in individuals with MECP2 variants associated with increased clinical severity. This normalized measure of RTT severity provides the opportunity for future discovery of additional factors contributing to disease severity that may be masked by age and genotype effects.
Collapse
Affiliation(s)
- Jonathan K. Merritt
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA;
| | - Xiaolan Fang
- Department of Pathology, Henry Ford Health System, Detroit, MI 48202, USA;
- Greenwood Genetic Center, Greenwood, SC 29646, USA; (R.C.C.); (S.A.S.); (M.J.F.)
| | - Raymond C. Caylor
- Greenwood Genetic Center, Greenwood, SC 29646, USA; (R.C.C.); (S.A.S.); (M.J.F.)
| | - Steven A. Skinner
- Greenwood Genetic Center, Greenwood, SC 29646, USA; (R.C.C.); (S.A.S.); (M.J.F.)
| | - Michael J. Friez
- Greenwood Genetic Center, Greenwood, SC 29646, USA; (R.C.C.); (S.A.S.); (M.J.F.)
| | - Alan K. Percy
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL 35294, USA;
| | - Jeffrey L. Neul
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA;
- Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| |
Collapse
|
2
|
Zade K, Campbell C, Bach S, Fernandes H, Tropea D. Rett syndrome in Ireland: a demographic study. Orphanet J Rare Dis 2024; 19:34. [PMID: 38291497 PMCID: PMC10829226 DOI: 10.1186/s13023-024-03046-8] [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: 09/04/2023] [Accepted: 01/19/2024] [Indexed: 02/01/2024] Open
Abstract
BACKGROUND Rett syndrome (RTT) is a rare neurodevelopmental condition associated with mutations in the gene coding for the methyl-CpG-binding protein 2 (MECP2). It is primarily observed in girls and affects individuals globally. The understanding of the neurobiology of RTT and patient management has been improved by studies that describe the demographic and clinical presentation of individuals with RTT. However, in Ireland, there is a scarcity of data regarding individuals with RTT, which impedes the ability to fully characterize the Irish RTT population. Together with the Rett Syndrome Association of Ireland (RSAI), we prepared a questionnaire to determine the characteristics of RTT individuals in Ireland. Twenty-five families have participated in the study to date, providing information about demographics, genetics, familial history, clinical features, and regression. RESULTS The results show that Irish individuals with RTT have comparable presentation with respect to individuals in other countries; however, they had a better response to anti-epileptic drugs, and fewer skeletal deformities were reported. Nonetheless, seizures, involuntary movements and regression were more frequently observed in Irish individuals. One of the main findings of this study is the limited genetic information available to individuals to support the clinical diagnosis of RTT. CONCLUSIONS Despite the limited sample size, this study is the first to characterize the RTT population in Ireland and highlights the importance of having a swift access to genetic testing to sharpen the characterization of the phenotype and increase the visibility of Irish individuals in the international RTT community.
Collapse
Affiliation(s)
- Komal Zade
- Department of Psychiatry, School of Medicine, Trinity Centre for Health Sciences, Trinity College Dublin, St James Hospital, Dublin, D08 W9RT, Ireland
| | - Ciara Campbell
- Department of Psychiatry, School of Medicine, Trinity Centre for Health Sciences, Trinity College Dublin, St James Hospital, Dublin, D08 W9RT, Ireland
| | - Snow Bach
- Department of Psychiatry, School of Medicine, Trinity Centre for Health Sciences, Trinity College Dublin, St James Hospital, Dublin, D08 W9RT, Ireland
| | - Hazel Fernandes
- Consultant Child and Adolescent Psychiatrist, Barnet, Enfield and Haringey Mental Health NHS Trust, London, UK
| | - Daniela Tropea
- Department of Psychiatry, School of Medicine, Trinity Centre for Health Sciences, Trinity College Dublin, St James Hospital, Dublin, D08 W9RT, Ireland.
- Neuropsychiatric Genetics, Department of Psychiatry, School of Medicine, Trinity College Dublin, Trinity Translational Medicine Institute, St James's Hospital, Dublin, Ireland.
- Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland.
- FutureNeuro, The SFI Research Centre for Chronic and Rare Neurological Diseases, Dublin, Ireland.
| |
Collapse
|
3
|
Lopes AG, Loganathan SK, Caliaperumal J. Rett Syndrome and the Role of MECP2: Signaling to Clinical Trials. Brain Sci 2024; 14:120. [PMID: 38391695 PMCID: PMC10886956 DOI: 10.3390/brainsci14020120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/11/2024] [Accepted: 01/17/2024] [Indexed: 02/24/2024] Open
Abstract
Rett syndrome (RTT) is a neurological disorder that mostly affects females, with a frequency of 1 in 10,000 to 20,000 live birth cases. Symptoms include stereotyped hand movements; impaired learning, language, and communication skills; sudden loss of speech; reduced lifespan; retarded growth; disturbance of sleep and breathing; seizures; autism; and gait apraxia. Pneumonia is the most common cause of death for patients with Rett syndrome, with a survival rate of 77.8% at 25 years of age. Survival into the fifth decade is typical in Rett syndrome, and the leading cause of death is cardiorespiratory compromise. Rett syndrome progression has multiple stages; however, most phenotypes are associated with the nervous system and brain. In total, 95% of Rett syndrome cases are due to mutations in the MECP2 gene, an X-linked gene that encodes for the methyl CpG binding protein, a regulator of gene expression. In this review, we summarize the recent developments in the field of Rett syndrome and therapeutics targeting MECP2.
Collapse
Affiliation(s)
- Adele Gaspar Lopes
- Department of Pharmacology, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3G 2M1, Canada
- Cancer Research Program, Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1, Canada
| | - Sampath Kumar Loganathan
- Cancer Research Program, Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1, Canada
- Department of Biochemistry, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H4A 3J1, Canada
- Department of Otolaryngology, Head & Neck Surgery, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H4A 3J1, Canada
- Departments of Experimental Surgery and Experimental Medicine, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H4A 3J1, Canada
| | - Jayalakshmi Caliaperumal
- Ingram School of Nursing, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3A 2M7, Canada
| |
Collapse
|
4
|
Kay C, Leonard H, Smith J, Wong K, Downs J. Genotype and sleep independently predict mental health in Rett syndrome: an observational study. J Med Genet 2023; 60:951-959. [PMID: 37055168 DOI: 10.1136/jmg-2022-108905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 03/26/2023] [Indexed: 04/15/2023]
Abstract
BACKGROUND Rett syndrome is a genetically caused neurodevelopmental disorder associated with severe impairments and complex comorbidities. This study examined predictors of anxiety and depression in Rett syndrome, including genotype. METHODS The International Rett Syndrome Database, InterRett, was the data source for this observational study. Associations between genotype, functional abilities, comorbidities, anxiety and depression were estimated with univariate and multivariate regression models. An additional regression model for anxiety included use of an anxiety medication as a predictor variable. RESULTS The sample included 210 individuals aged 6-51 years of whom 54 (25.7%) were on psychotropic medication for anxiety or depression. Individuals with the p.Arg294* variant had the highest anxiety scores, as did those with insomnia or excessive daytime sleepiness, irrespective of anxiety medication use. Individuals with the p.Arg306Cys variant had the lowest depression scores, as did those with insomnia or excessive daytime sleepiness. CONCLUSION Findings indicated that genotype and sleep have implications for mental health in Rett syndrome, suggesting that anticipatory guidance and proactive management of poor sleep could improve mental health. More research is needed to understand the effects of psychometric medications, which cannot be inferred from this cross-sectional study.
Collapse
Affiliation(s)
- Cayla Kay
- School of Human Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Helen Leonard
- Telethon Kids Institute, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Jeremy Smith
- School of Human Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Kingsley Wong
- Telethon Kids Institute, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Jenny Downs
- Telethon Kids Institute, The University of Western Australia, Nedlands, Western Australia, Australia
- Curtin School of Allied Healt, Curtin University, Perth, Western Australia, Australia
| |
Collapse
|