Rett syndrome

Introduction

Rett's syndrome (Rett syndrome, Rett's disorder) is a progressive neurological disorder, one of the leading disorders of mental retardation in females. The symptoms of this disorder are easily confused with those of autism and cerebral palsy.

Etiology

Rett syndrome is an X-linked, dominant disorder, caused by a mutation in the gene encoding methyl-CpG-binding protein-2 (MECP2). The Rett gene (symbolized RTT) is found on the chromosome band Xq28, near the long end of the X chromosome. This disorder affects 1 in every 12,500 live births. The combination of an RTT gene-containing X chromosome with the Y chromosome is lethal gene combination, resulting in spontaneous abortion. Males who have two X chromosomes, one with the Rett gene,follow a similar development to women with Rett syndrome.

Development and Symptoms

Infants typically develop normally up to age 6-18 months. Physioneurological development tends to plateau after this brief period of normal development, and is followed by deterioration of high brain functions. Psychomotor and cognitive abilities rapidly decline within 1-2 years of age. Symptoms that develop are autistic-like, with mental retardation and poor growth. It is, hence, easy for the misdiagnosis of Rett for autism, or cerebral palsy. Autistic-like symptoms in Rett disorder:

screaming fits
panic-like attacks
inconsolable crying
avoids looking into other people's eyes
lack of social/emotional reciprocity
general lack of interest
marked impairment of use of nonverbal behaviors to regulate social interaction
delay of linguistic development
* loss of speech

Symptoms in Rett that are also present in cerebral palsy:

short stature
slight to severe mental retardation
severe dementia
mild learning disability
hypotonia
gait/movement difficulties
ataxia
microencephalopathy - abnormally small head, lack of head growth
some forms of spasticity
* wringling of hands
* chorea - spasmodic movements of hand or facial muscles
* dystonia
* bruxism - grinding of teeth

Symptoms may stabilize for up to a few decades before complications set in, such as:

epilepsy/seizure
spastic paraparesis - spasticity or paralysis of the lower limbs

Treatment & Prognosis

Depending of severity of psychomotor, cognitive impairment, 2-15% of patients may achieve a nonretarded level of cognitive and adaptive functioning through various rehabilitation methods. Marriage, success in achieving employment, independent residence can be achieved during adulthood. There is no current cure for Rett disorder. Treatment of Rett disorder briefly includes:

increasing communication skills
counseling
modifying social difficulties
behavioral interventions

Treatment usually requires consultantions from:

speech and language therapist
psychologist/counselor
neurologist/neuropsychiatrist

Common prescriptions:

antidepressants
* SSRIs
antipsychotics
beta-blockers
opioid antagonists

Mortality

Males born with Rett often die during infancy stage from severe encephalopathy. Females can live up to 40 years or more. Abnormal lab data values on Rett disorder may show:

EEG abnormalities from 2 years of age
atypical glycolipids
elevated levels of beta-endorphins and glutamate
reduction of substance P
decreased levels of nerve growth factors

Mortality rate among children with Rett disorder is approximately at 1.2% per year. High proportion of deaths are abrupt; due to:

heart conduction problem - abnormally prolonged QT interval on ECG
spontaneous brainstem dysfunction
respiratory arrest

External links

eMedicine.com MedicineNet.com NIH The International Rett Syndrome Association Category:Neurology Category:Eponymous diseases fr:Syndrome de Rett nl:Syndroom van Rett