Atypical Rett syndrome

[MIM 300 672, 312 750, 613 454]

(FOXG1, syndrome Rett-like syndrome)

Prevalence 1/45.000.  X-linked or autosomal dominant transmission. This encephalopathy mostly affects girls.

Several forms:

-        form with early seizures (Hanefeld type): mutation of the CDKL5 gene (Xp22)

-        congenital form (Rolando type); mutation of the FOXG1 gene (14q11-q13); retardation of overall development without regression, hypotonia, abnormal movements (dystonia, myoclonus),  gastroesophageal reflux, microcephaly, abnormal corpus callosum and delayed myelinisation at MRI; in case of 14q12 deletion, a facial dysmorphism is associated.

-        form with preservation of speech (Zappela type): mutation of the MECP2 gene (Xq28) as in the classic form.


The clinical presentation is very variable.



  Diagnostic criteria of Rett-like syndrome

A period of regression followed by a phase of recovery or stabilization is necessary

and the presence of at least 2 of 4 major criterias

                                                  5 of 11 accessory criterias


Major criteria

-        partial or complete loss of voluntary use of hands

-        partial or complete loss of speech

-        walking disorders: unstable or absent walking ability

-        characteristic manual stereotypes : pressure/torsion, applause signs, brushing/cleaning of hands


Accessory criteria

-        respiratory dysfunction: episodes of apnea while awake, of intermittent hyperventilation, of respiratory blockade, of forced expectoration of air or saliva

-        vigil bruxism

-        sleep disorders

-        tonus disorders

-        vasomotor disorders

-        scoliosis/cyphosis

-        growth retardation

-        small hands or feet, hypotrophism

-        inappropriate laughing or screaming or crying

-        decreased pain sensitivity

-        communication through intense gaze


Diagnostic criteria of exclusion:
brain lesions of perinatal or postnatal origin , metabolic disorders, progressive neurologic disease




Anesthetic implications:

epilepsy, variable degree of mental retardation. See Rett syndrome for the respiratory implications. Risk of decreased pain sensitivity.


References :

       


Updated: May 2018