Glossary & FAQ
Explore our glossary and FAQ section for detailed explanations and answers to common questions about Rett syndrome. This resource is designed to support families, caregivers, and anyone looking to deepen their understanding of Rett syndrome terminology and concepts.
Frequently Asked Questions
Get quick answers to frequently asked questions about Rett syndrome, from symptoms and diagnosis to research and treatments.
What is Rett syndrome (RTT)?
Rett syndrome (RTT) is a rare and devastating neurodevelopmental disorder that impacts nearly every aspect of an individual’s life, including their ability to speak, walk, eat, and even breathe. Any racial or ethnic group can experience Rett syndrome and while it most commonly occurs in females (approximately 1 in 10,000 births worldwide), males can have Rett too, often experiencing earlier and more severe symptoms.
What causes Rett? Is it genetic?
Rett syndrome is a genetic disorder. It is caused by a spontaneous pathogenic variant—or mutation—on a gene called MECP2 that is located on the X chromosome in >96% of clinically diagnosed individuals. This gene is important for brain development and for activating and deactivating other gene functions. When the MECP2 gene does not function properly, it can cause issues throughout the entire body.
Percy, A.K., Ananth, A. & Neul, J.L. Rett Syndrome: The Emerging Landscape of Treatment Strategies. CNS Drugs (2024). https://doi.org/10.1007/s40263-024-01106-y
Is Rett syndrome inherited?
Rett syndrome is not considered to be inherited. The MECP2 variant is currently believed to be de novo, passed from parent to child in less than 1% of recorded cases.
NIH (https://www.ninds.nih.gov/health-information/disorders/rett-syndrome)
Is there a treatment or cure for Rett syndrome?
There is currently no cure for Rett syndrome, but in March 2023, the U.S. Food and Drug Administration (FDA) approved trofinetide for the treatment of Rett syndrome. Now marketed under the name DAYBUE™ by Acadia Pharmaceuticals, this first-ever drug treatment is available in the United States and approved for all individuals with Rett syndrome – male and female – aged two and older with no upper limit, and was recently approved by Health Canada for expansion. You can find more information at daybue.com.
Acadia Pharmaceuticals Inc. owns the rights to trofinetide in North America and acquired the rights in the rest of the world in July 2023. Initially prioritizing the regulatory activities in Europe and Japan, they are assessing potential regulatory pathways and market dynamics, and are evaluating a variety of pathways to make trofinetide available worldwide. We recommend reaching out to Acadia directly for more information.
How will Rett syndrome affect our family’s daily life?
Living with Rett syndrome can bring a range of challenges, but it can also be a journey full of resilience and support. The impact on your daily life will vary depending on your loved one’s unique needs, age, and symptoms, but issues like communication, mobility, feeding and nutrition, and sleep disruptions may shape your daily routine. Additionally, doctor’s visits and therapies like occupational, physical, and speech therapy may become regular parts of your life.
Are there any clinical trials or studies that I can participate in?
There are many clinical trials actively recruiting patients. You can find information about current clinical trial opportunities in Rett syndrome through our myRett Trial Finder tool. The tool provides clear and easy-to-search information related to all Rett syndrome clinical trials listed on clinicaltrials.gov and additional research opportunities from around the world, such as neuro-habilitative and observational studies and surveys.
How can I meet other families living with Rett?
IRSF offers many ways to connect with the Rett community, both in-person and virtually. We host events across the U.S. for families like our Strollathons, RettEd Days, and ASCEND National Summit, and offer group forums on Facebook for open discussion. We also offer a list of regional and international Rett syndrome associations to make it easy to connect with families near you.
How can I donate to IRSF?
CLICK HERE to make a one-time donation or set up a recurring gift. You can choose to give to a specific program or to where support is needed most. You can also donate by phone at (800) 818-7388 or mail a check payable to International Rett Syndrome Foundation to 4500 Cooper Road, Ste 204, Cincinnati, OH 45242.
What events are happening in my area?
Our events calendar features educational opportunities, fundraisers, and more. Visit our event calendar to find an event near you.
I'm a Rett researcher. Where can I learn about your funding opportunities?
Visit our Funding Opportunities page to learn more about current funding offered through IRSF and to sign up for our quarterly newsletter that features a comprehensive list of funding opportunities outside the Foundation.
I work in biopharma or industry. How can I partner with IRSF?
Visit our Industry Partners page to learn more about the resources we offer and ways to contact us.
What are the symptoms of Rett Syndrome?
Every individual with Rett is unique and so are their symptoms and severity. These can include near-constant repetitive hand movements, seizures, scoliosis, digestive problems, and breathing issues. Symptoms most often begin with a period of regression as early as 6 months old when parents begin to see their child miss development milestones and lose abilities they had already gained. Rett syndrome is not a degenerative disorder. Barring illness or complications, individuals with Rett can live into adulthood and beyond, but require lifelong care.
How is Rett syndrome diagnosed?
Rett syndrome is considered a clinical diagnosis. Unfortunately, individuals often receive incorrect or delayed diagnosis because in its early stages, RTT shares many clinical symptoms with other, more common neurological and developmental disorders like autism, cerebral palsy, and epilepsy.
To confirm a Rett syndrome diagnosis, a doctor will evaluate an individual based on a list of diagnostic criteria created by Rett clinical experts. The diagnosis will be either typical RTT where all clinical criteria are met or atypical RTT where only some of the criteria are met. Genetic testing can confirm the clinical diagnosis; however, the presence of a MECP2 mutation without the clinical features is not sufficient for a diagnosis of RTT.
Neul JL, Kaufmann WE, Glaze DG, Christodoulou J, Clarke AJ, Bahi-Buisson N, Leonard H, Bailey ME, Schanen NC, Zappella M, Renieri A, Huppke P, Percy AK; RettSearch Consortium. Rett syndrome: revised diagnostic criteria and nomenclature. Ann Neurol. 2010 Dec;68(6):944-50. doi: 10.1002/ana.22124. PMID: 21154482; PMCID: PMC3058521. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3058521/
My child was just diagnosed with Rett. What happens now?
Receiving a Rett syndrome diagnosis can be overwhelming, and you might not know where to begin. But know that you are not alone. Visit our Newly Diagnosed page to learn about recommendations for next steps, including registering with IRSF. This is often the first step in receiving the support and resources you need to empower your family.
How do I find a doctor who specializes in Rett syndrome?
IRSF is committed to ensuring that families have easy access to a clinic with Rett syndrome expertise. We recognize a network of 21 clinics across the United States as Centers of Excellence for best-in-class Rett syndrome care.
We also make resources available to help your local clinician learn about treating a patient with Rett syndrome and gain mentoring from experts in the field in our Clinics & Providers section.
What research is being done right now to advance treatments and cures for Rett syndrome?
Hundreds of scientists and researchers around the world are studying Rett syndrome, many with the support of IRSF funding. They are exploring deepening our understanding of MeCP2 and advancing promising strategies to treat and cure Rett, including gene therapy, RNA-based therapies, small molecules, X-reactivation, and more.
IRSF currently funds 25 research projects through our highly comprehensive scientific program. These projects cover Rett research at all levels, including the advancement of genetic approaches and developing drugs that improve quality of life, as well as the development of a clinical research network to bring treatments to families.
What resources does IRSF offer for to help families living with a loved one with Rett syndrome?
IRSF empowers families with the tools, resources, and connections needed for every step of the Rett journey. Explore our “For Families” section for care guidelines, community connection opportunities, and more.
How can I learn more about Rett syndrome and how to better care for my child?
Explore our website to learn about Rett syndrome and register with IRSF to receive the most up-to-date resources to care for your loved one with Rett. Additionally, IRSF hosts educational webinars, in-person RettEd Days at COE clinics, and a national conference that allows families to directly connect with experts and other families.
How can I plan an event to support IRSF?
There are many types of events you can host to support IRSF’s mission, from independent fundraisers using our giving platform to partnered events and Strollathons. Our team makes planning easy and can provide resources to help your event succeed. Contact our Events Manager to learn more and get started!
What is the ASCEND Rett Syndrome National Summit?
The ASCEND National Summit is a premier event hosted by IRSF, bringing together families, clinicians, researchers, and Rett organizations from around the world. This biennial gathering features expert-led sessions, interactive breakouts, and keynote presentations on the latest in Rett syndrome research, treatments, and care. Attendees can also connect through engaging social activities and explore an exhibitor hall showcasing innovative products, services, and treatments tailored for individuals with Rett syndrome.
I'm a healthcare provider looking for information. Where should I start?
Visit our Clinics & Providers page to learn more about CME opportunities, treatment options, and how to connect with experts in Rett syndrome.
Glossary
Get familiar with key terms related to Rett syndrome to navigate the complex language of genetics, neurology, and care practices.
A
Adverse Event (AE)
Any undesirable experience associated with a medical treatment.
Antisense Oligonucleotides (ASOs)
A therapeutic approach under research for genetic disorders like Rett.
Apraxia
Inability to perform coordinated movements, common in Rett syndrome.
Atypical Rett Syndrome
Variants of Rett syndrome that don’t meet the classic criteria.
Autosomal Dominant
The inheritance pattern of Rett syndrome.
B
Biomarker
Biological markers used to track disease progression or treatment response.
Breathing Irregularities
Common in Rett syndrome, includes hyperventilation and breath-holding.
C
Caregiver Burnout
Emotional and physical exhaustion from long-term caregiving responsibilities.
Clinical Trial
A research study to evaluate medical treatments, relevant for Rett therapies.
Constipation
A common condition that occurs when you have infrequent bowel movements or have difficulty passing stools; very common for those with Rett syndrome.
CPT Coding for Rett Syndrome
Medical billing codes relevant to Rett syndrome treatments.
CRISPR
A gene-editing technology with potential applications for Rett syndrome.
Cure
The complete and permanent reversal or elimination of a disease and its symptoms. In the case of Rett syndrome, a cure would involve fully restoring the individual’s neurodevelopmental function by addressing the root genetic cause, though this remains an area of ongoing research. Cures differ from treatments, which aim to manage symptoms rather than completely eliminate the disease.ure generations.
D
Daybue (trofinetide)
The first FDA-approved treatment for Rett syndrome.
Double-Blind Study
A clinical study in which neither participants nor researchers know who receives the treatment.
Dysautonomia
Dysfunction of the autonomic nervous system, affecting heart rate, breathing, etc.
Dystonia
Involuntary muscle contractions causing repetitive movements or abnormal postures. Common in Rett syndrome, it may affect comfort and mobility and can be managed with therapies or medications.
E
Enzyme Replacement Therapy
A treatment approach explored in some genetic disorders, not yet used for Rett.
Epigenetics
The study of how genes like MECP2 are regulated and expressed.
Eye-Gaze Communication
A method of communication, using eye movement in combination with special technology, often useful for individuals with Rett who have limited verbal skills.
G
Gait Abnormalities
Difficulties with walking or balance often seen in Rett syndrome.
Gene
A segment of DNA that contains instructions for building proteins, which carry out essential functions in the body. In Rett syndrome, mutations in the MECP2 gene disrupt normal brain development, leading to the condition’s symptoms.
Gene Therapy
A treatment approach that aims to correct or replace faulty genes responsible for a disease. In Rett syndrome, gene therapy research focuses on restoring or compensating for the function of the MECP2 gene, with the goal of reducing symptoms or reversing the condition’s effects.
I
Informed Consent
The process by which participants understand and agree to participate in clinical research.
L
Loss of Purposeful Hand Use
A hallmark of Rett syndrome, often involving difficulty in using hands for tasks.
M
MECP2
The gene most commonly associated with Rett syndrome.
Microcephaly
Smaller-than-average head size, often seen in Rett syndrome.
Mitochondrial Dysfunction
A common issue in Rett syndrome, affecting energy production in cells.
Multidisciplinary Care
A healthcare approach involving various specialists, common in Rett treatment.
N
Neurodevelopmental Disorder
A disorder affecting brain development, like Rett syndrome.
O
Orphan Drug
A drug developed to treat rare diseases like Rett syndrome.
P
Palliative Care
Supportive care focusing on relieving symptoms and improving quality of life.
Patient Advocacy
Efforts by individuals and organizations to influence health policy or research.
Pharmacokinetics
The study of how drugs are absorbed, distributed, and metabolized in the body.
Placebo
A substance with no therapeutic effect, often used in clinical trials.
Principal Investigator (PI)
The lead researcher in a clinical trial.
Q
Quality of Life (QoL)
A measurement of a patient’s well-being and life satisfaction.
R
Randomized Controlled Trial (RCT)
A clinical trial design used to assess the efficacy of treatments.
Rare Disease
A condition affecting fewer than 200,000 people in the U.S.
Regression
A phase in Rett syndrome where a child loses previously acquired skills.
S
Safety Profile
A description of the side effects and risks associated with a treatment.
Scoliosis
A common spinal curvature disorder seen in Rett syndrome patients.
Seizures
A temporary episode of abnormal electrical activity in the brain that can cause a person to experience a sudden change in behavior, movement, or consciousness; very common symptom in Rett syndrome.
Supportive Therapies
Therapies like physical therapy, occupational therapy, and speech therapy.
T
Treatment
The chromosome where the MECP2 gene is located.
X
X-Chromosome
The chromosome where the MECP2 gene is located.
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