Rett syndrome

[MIM 312 750]

Prevalence: 1/10,000 to 20,000 female births. X-linked dominant transmission of a mutation in the MECP2 gene on Xq28. Progressive encephalopathy. The coded protein is important for the neuronal development and even for regulation of the µ opioid receptors.


Development is normal up to the age of 6-18 months and then one observes an evolution in 4 stages:

-        I: onset of stagnation: arrest of psychomotor development;

-        II: followed by a rather fast (before the age of 1 year) regression with loss of communication, appearance of the stereotyped gestures, autistic behavior, respiratory disorders  (periods of hyperventilation interrupted by apnea); progressive microcephaly following diffuse cerebral atrophy.

-        III: then, a period of relative stabilization (years) with some recovery of communication skills,  preserved wolking, apraxia, convulsions, kyphoscoliosis.

-        IV: late deterioration: spasticity, dystonia, impossible walking, amyotrophy with trophic disorders of the limbs (years).


Frequently: aerophagia, seizures.

There is sometimes a decreased sensitivity to pain, bouts of sinus bradycardia, especially during sleep, long QT secondary to prolonged apnea. Decrease in vagal tone with episodes of tachycardia and hypertension. Risk of sudden death from cardiac causes.


Respiratory disorders  while awake are classified into 3 categories:

*        chronic hyperventilation with lowPaCO2  ("forceful breathers")

*        chronic hypoventilation with high PaCO2  ('feeble breathers")

*        episodes of apnea with accumulation of CO2 (®apneustic breathers")

Sometimes obstructive apnea syndrome during sleep.

Risk of chronic pulmonary inflammation caused by recurrent episodes of aspiration (saliva, gastric content) with progressive appearance of apical bullae.

Palliative treatment (improvement of the behavior disorders): trofinetid (synthetic analog of the aminoterminal tripetide, glycin prolin glutamate of IGF-1 (growth factor 1, analog of insuline) orally 2x/day.


Anesthetic implications:

basal level of endorphins often increased; try to determine the type of respiratory disorders while awake as a  increased sensitivity to morphine and sedatives is observed in the 'feeble breathers" (p ex: with propofol, more respiratory complications despite lower doses ). Postoperative monitoring of respiration and ECG. Management of a polyhandicapped and frequently epileptic child. Recent data show that those girls seem to need less opioids after scoliosis surgery than other polyhandicapped children benefiting of the same surgery.


References : 


Updated: March 2023