RS is a clinical diagnosis based on symptoms.  At this time, approximately 75% of all patients diagnosed with RS also test positive for a MECP2 mutation.  This does not mean that the remaining 25% do not have RS.  Although testing positive for a mutation confirms the diagnosis it is not required for one.  (Laboratories testing for MECP2 Mutations)  The criteria below are used for making a diagnosis of RS.  Please keep in mind that RS is a spectrum disorder.  Not all the symptoms are seen in every patient and the severity of a symptom may vary widely from patient to patient.

Diagnostic Criteria

  • Period of apparent normal development until 6-18 months (some girls have an earlier onset of RS symptoms and therefore have no apparently normal period of development).
  • Normal head circumference at birth followed by slowing of the rate of head growth (there is a subset of girls whose head circumference does not decelerate).
  • Loss of verbal language.
  • Purposeful hand use is replaced by stereotypical hand movements (these can include a multitude of hand movements, some girls have movements unique to them).
  • If able to walk the gait is usually wide-based and stiff legged.
  • Shakiness of torso and/or limbs, especially when upset.
  • Supportive Criteria
  • Breathing pattern irregularities which include hyperventilation, breath holding, apnea, air swallowing
  • EEG abnormalities
  • Seizures
  • Scoliosis
  • Teeth grinding
  • Gastrointestinal issues which may include reflux, constipation, poor nutrient absorption
  • Growth retardation and decreased body fat and muscle mass
  • Biting/Chewing/Swallowing difficulties
  • Poor circulation to legs and feet
  • Decreased mobility with age
  • Muscle rigidity/spasticity/joint contractures
  • Small feet
  • Abnormal sleep patterns
  • Irritability and agitation

Reprinted by permission from the
Rett Syndrome Research Foundation
4600 Devitt Drive
Cincinnati, Ohio 45246
Phone: 513-874-3020
Fax: 513-874-2520

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