Diagnosing Rett syndrome involves careful observation of your child's growth and development and answering questions about medical and family history. The diagnosis is usually considered when slowing of head growth is noticed or loss of skills or developmental milestones occurs.
For a diagnosis of Rett syndrome, other conditions with similar symptoms must be ruled out.
Evaluating other causes for the symptoms
Because Rett syndrome is rare, your child may have certain tests to determine whether other conditions are causing some of the same symptoms as Rett syndrome. Some of these conditions include:
- Other genetic disorders
- Autism spectrum disorder
- Cerebral palsy
- Hearing or vision problems
- Metabolic disorders, such as phenylketonuria (PKU)
- Disorders that cause the brain or body to break down (degenerative disorders)
- Brain disorders caused by trauma or infection
- Brain damage before birth (prenatal)
What tests your child needs depends on specific signs and symptoms. Tests may include:
- Blood tests
- Urine tests
- Imaging tests such as magnetic resonance imaging (MRI) or computerized tomography (CT) scans
- Hearing tests
- Eye and vision exams
- Brain activity tests (electroencephalograms, also called EEGs)
Core symptoms
Diagnosis of classic Rett syndrome includes these core symptoms, which may start to show up anytime from 6 to 18 months of age:
- Partial or complete loss of purposeful hand skills
- Partial or complete loss of spoken language
- Walking problems, such as difficulty walking or not being able to walk
- Repetitive purposeless hand movements, such as hand-wringing, squeezing, clapping or tapping, putting hands in the mouth, or washing and rubbing movements
Additional symptoms that typically occur with Rett syndrome can support the diagnosis.
Guidelines for diagnosis of atypical Rett syndrome may vary slightly, but the symptoms are the same, with varying degrees of severity.
Genetic testing
If your child's health care provider suspects Rett syndrome after evaluation, genetic testing (DNA analysis) may be needed to confirm the diagnosis. The test requires drawing a small amount of blood from a vein in your child's arm. The blood is then sent to a lab, where the DNA is examined for clues about the cause and severity of the disorder. Testing for changes in the MEPC2 gene confirms the diagnosis. Genetic counseling can help you understand gene changes and their effects.