Rett syndrome
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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
Symptoms may stabilize for up to a few decades before complications set in, such as:
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:
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 (http://www.emedicine.com/med/topic3202.htm)
MedicineNet.com (http://www.medterms.com/script/main/art.asp?articlekey=11960)
NIH (http://www.ninds.nih.gov/health_and_medical/disorders/rett_doc.htm)
The International Rett Syndrome Association (http://www.rettsyndrome.org/)fr:Syndrome de Rett nl:Syndroom van Rett