The essential criteria for a medical diagnosis of Rett syndrome were redefined in 2010 and are as follows:
- A period of regression during the first 5 years of life followed by a relatively stable period
- Partial or complete loss of acquired purposeful hand skills
- Partial or complete loss of acquired spoken language
- An impaired ability to coordinate walking or an absence of the ability to walk
- Repetitive non-purposeful hand movements such as wringing/squeezing, clapping/tapping, mouthing, weashing/rubbing.
If all of these symptoms exist or existed, a label of ‘classic‘ or ‘typical‘ Rett syndrome is used.
In addition to all or some of the above, other symptoms that may be present or may have been experienced, can include:
- Breathing disturbances while awake
- Inappropriate laughing and/or screaming spells
- Teeth grinding
- Diminished response to pain
- Disturbed sleep pattern
- Intense eye contact, use of the eyes to communicate
- Abnormal muscle tone
- Small cold hands and feet
- Curvature of the spine or neck.
The presence of these additional symptoms support a diagnosis of Rett syndrome.
Where an individual has or had an early period of regression and at least two but not all of the above essential criteria, a label of ‘classic‘ or ‘typical‘ Rett syndrome does not apply. However, if this individual has or had at least five of the additional symptoms, a label of ‘variant‘ or ‘atypical‘ Rett syndrome is used.
A diagnosis of ‘typical’ or ‘classic’ Rett syndrome cannot be given if one or more of the following apply:
- Brain injury subsequent to trauma around or soon after birth;
- A neurometabolic disease;
- A severe infection that caused problems of the nervous system;
- The child’s attainment over time of skills that involve both mental and muscular activity, such as the ability to roll over, sit, crawl, walk, talk, is grossly abnormal (grossly abnormal to the point that normal milestones such as acquiring head control, swallowing, or developing a social smile are not reached within the first 6 months of life).
Please note that a genetic test which reveals a mutation in the MECP2 gene, confirms the diagnosis already determined or suspected by a medical or other health professional.