National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Atypical Rett syndrome


Other Names:
Rett like syndrome; Rett syndrome variant
Categories:
Atypical Rett syndrome is a neurodevelopmental disorder that is diagnosed when a child has some of the symptoms of Rett syndrome but does not meet all the diagnostic criteria. Like the classic form of Rett syndrome, atypical Rett syndrome mostly affects girls. Children with atypical Rett syndrome can have symptoms that are either milder or more severe than those seen in Rett syndrome. Several subtypes of atypical Rett syndrome have been defined:[1]

  • The early-onset seizure type is characterized by seizures in the first months of life with later development of Rett features (including developmental problems, loss of language skills, and repeated hand wringing or hand washing movements). It is frequently caused by mutations in the X-linked CDKL5 gene (Xp22).
  • The congenital variant is the most severe form of atypical Rett syndrome, with onset of classic Rett features during the first three months of life. This variant is generally caused by mutations in the FOXG1 gene (14q11-q13).
  • The forme fruste is a milder variant with onset in early childhood and an incomplete and prolonged course.
  • The late childhood regression form is characterized by a normal head circumference and by a more gradual and later onset (late childhood) regression of language and motor skills.
  • The preserved speech variant is marked by recovery of some verbal and manual skills and is caused in at least some cases by mutations in the MECP2 (Xq28) gene, which is also responsible for the majority of cases of classic Rett syndrome.

Diagnosis relies on clinical evaluation using the diagnostic criteria for atypical Rett syndrome which was defined by Hagberg in 1994. Molecular genetic testing may confirm the diagnosis.[1]

Last updated: 2/12/2013

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Abnormal fingernail morphology
Abnormal fingernails
Abnormality of the fingernails
[ more ] 		0001231
Abnormality of movement
Movement disorder
Unusual movement
[ more ] 		0100022
Abnormality of the antitragus 0009896
Abnormality of the metacarpal bones
Abnormality of the long bone of hand
0001163
Aplasia/Hypoplasia of the cerebellum
Absent/small cerebellum
Absent/underdeveloped cerebellum
[ more ] 		0007360
Camptodactyly of finger
Permanent flexion of the finger
0100490
Cerebral cortical atrophy
Decrease in size of the outer layer of the brain due to loss of brain cells
0002120
Clinodactyly of the 5th finger
Permanent curving of the pinkie finger
0004209
Developmental regression
Loss of developmental milestones
Mental deterioration in childhood
[ more ] 		0002376
EEG abnormality 0002353
Fine hair
Fine hair shaft
Fine hair texture
Thin hair shaft
Thin hair texture
[ more ] 		0002213
Gastroesophageal reflux
Acid reflux
Acid reflux disease
Heartburn
[ more ] 		0002020
Hearing impairment
Deafness
Hearing defect
[ more ] 		0000365
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation
[ more ] 		0001249
Long philtrum 0000343
Microcephaly
Abnormally small skull
Decreased circumference of cranium
Decreased size of skull
Reduced head circumference
Small head circumference
[ more ] 		0000252
Nephrolithiasis
Kidney stones
0000787
Seizure 0001250
Spasticity
Involuntary muscle stiffness, contraction, or spasm
0001257
Thick vermilion border
Full lips
Increased volume of lip
Plump lips
Prominent lips
Thick lips
[ more ] 		0012471
Underdeveloped nasal alae
Underdeveloped tissue around nostril
0000430
Ventriculomegaly 0002119
Wide mouth
Broad mouth
Large mouth
[ more ] 		0000154
Wide nose
Broad nose
Increased breadth of nose
Increased nasal breadth
Increased nasal width
Increased width of nose
[ more ] 		0000445
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Last updated: 7/1/2020
Treatment is symptomatic and supportive. Medication may be needed for breathing irregularities, sleep disturbances (melatonin), agitation (risperidone), rigidity and motor difficulties (levodopa and carbidopa), and to control seizures (antiepileptic drugs). Anti-reflux agents may also be required.[1]
Last updated: 4/5/2011

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

  • The International Rett Syndrome Foundation provides a list of specialty clinics for Rett syndrome.

Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
Differential diagnoses include Angelman syndrome, autism, cerebral palsy, inborn errors of metabolism and severe intellectual deficit (see these terms).
Visit the Orphanet disease page for more information.

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • The Rett Syndrome, MECP2 Duplications, & Rett-related Disorders Consortium is an integrated group of academic medical centers, patient support organizations, and clinical research resources dedicated to conducting clinical research into three disorders of the nervous system: Rett syndrome (RTT), MECP2 duplication disorder and RTT-related disorders. Major goals of the Consortium are to identify and understand the core clinical features of each disorder; identify factors that can modify the severity of the disorders; and understand the relationship between patients’ symptoms and their brain imaging and electroencephalography alterations. Click on the name of the study for more information.

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.

Education Resources

  • The Genetics Education Materials for School Success (GEMSS) aims to assure that all children with genetic health conditions succeed in school-life. Their Web site offers general and condition-specific education resources to help teachers and parents better understand the needs of students who have genetic conditions.

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know. Submit a new question

  • My daughter has been diagnosed with atypical Rett syndrome. How might this condition be treated? See answer


  1. Bienvenu T. Atypical Rett syndrome. Orphanet. 2009; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=3095. Accessed 4/5/2011.