Rett syndrome is most often misdiagnosed as autism, cerebral palsy, or non-specific developmental delay. There is a simple blood test to confirm the presence of the MECP2 mutation; however, since we know that the MECP2 mutation is also seen in other disorders, the presence of the MECP2 mutation in itself is not enough for the diagnosis of Rett syndrome. Diagnosis requires either the presence of the mutation (a molecular diagnosis) or fulfillment of the diagnostic criteria (a clinical diagnosis, based on observed signs and symptoms) or both. Below is a list of labs to share with your ordering physician that can do the MECP2 sequencing + deletion analysis, and the list of diagnostic criteria.
Required for typical or classic Rett
A period of regression followed by recovery or stabilization
All main criteria and all exclusion criteria
Supportive criteria are not required, although often present in typical Rett
Exclusion criteria for typical RTT
Brain injury secondary to trauma
Neurometabolic disease
Severe infection that causes neurological problems
Grossly abnormal psychomotor development in first 6 months of life
Required for atypical or variant Rett
A period of regression followed by recovery or stabilization
At least 2 of the 4 main criteria and 5 out of 11 supportive criteria
Main Criteria
Partial or complete loss of acquired purposeful hand skills
Partial or complete loss of acquired spoken language
Gait abnormalities: Impaired (dyspraxic) or absence of ability
Stereotypic hand movements such as hand wringing/squeezing, clapping/tapping, mouthing and washing/rubbing automisms
Supportive Criteria
Breathing disturbances when awake
Bruxism when awake
Impaired sleep pattern
Abnormal muscle tone
Peripheral vasomotor disturbances
Scoliosis/kyphosis
Growth retardation
Small cold hands and feet
Inappropriate laughing/screaming spells
Diminished response to pain
Intense eye communication—eye pointing
www.rettsyndrome.org