RETT SYNDROME (OR RETT'S
Rett syndrome, also known as Rett’s disorder,
is a progressive neurological disorder. It is one of the less common
Autism Spectrum Disorders, also known as Pervasive Developmental
Disorders. The symptoms of this disorder are easily confused with
those of cerebral palsy. The clinical diagnosis specifies a small
head and small hands and feet. Stereotypical repetitive hand movements
such as mouthing or wringing of the hands are also included as diagnostic
signs. Symptoms of the disease include learning disorders and a
total inability to socialize. Girls with Rett syndrome are very
prone to seizures and gastrointestinal disorders. They typically
have no verbal skills, and about 50% of females are ambulatory.
Cause of rett syndrome
Rett syndrome is linked to the X chromosome so
it almost exclusively affects girls. Development is normal until
six to18 months of age, when language and motor milestones regress,
purposeful hand use is lost and acquired microcephaly is seen. Hand-wringing
and sighing are characteristic, and those affected develop autistic
behavior. Rett syndrome is usually caused by a mutation in the gene
encoding methyl-CpG-binding protein-2 (MECP2). Rett syndrome can
also be caused by a mutation to the gene encoding cyclin-dependent
kinase-like 5 (CDKL5). Rett syndrome affects around one in every
12,500 female live births.
gender and rett syndrome
Most individuals with Rett syndrome are female.
One explanation given for this was that the genetic defect that
caused Rett syndrome in females caused embryonic lethality in males
(that is, males with pathogenic MECP2 mutations died before they
were born). While a plausible hypothesis, more recent research has
contradicted this explanation.
Most males with a pathogenic MECP2 mutation suffer from neonatal
encephalopathy and die within a year or so of birth. Males who have
two X chromosomes and a Y chromosome (often called Klinefelter’s
syndrome), one with a mutated MECP2 gene, follow a similar development
path to females with Rett syndrome. Males who have somatic mosaicism
also have symptoms like females with Rett syndrome.
The severity of Rett syndrome in females can vary depending on the
pattern of X-chromosome inactivation. In most cases, 50% of cells
use the maternal X chromosome while the other 50% uses the paternal
X chromosome. However, if most cells in the brain activate the X
chromosome with the functional MECP2 allele, the individual will
have very mild Rett syndrome; likewise, if most neurons activate
the X chromosome with the mutated MECP2 allele, the individual will
have very severe Rett syndrome and most likely die very early, just
as males with MECP2 mutations do, as they only have one X chromosome.
Some researchers have reported cases of males with Rett syndrome
who have a pathogenic MECP2 mutation but do not have a somatic mosaicism
or an extra chromosome.
Unlike most genetic diseases, many cases of Rett syndrome involve
spontaneous mutations in one of the parent’s gonads. It has been
argued that one cause of the majority of Rett syndrome individuals
being female is that mutations to MECP2 are possibly more common
in male gonads than female gonads, and only females can inherit
a mutated MECP2 gene from fathers (males inherit a Y chromosome
from fathers, which does not contain a copy of MECP2).
Development of rett syndrome
Infants with Rett syndrome typically develop normally
until they are six to 18 months old. Physioneurological development
tends to plateau after this brief period of normal development,
and is followed by deterioration of the higher brain functions.
Psychomotor and cognitive abilities rapidly decline between one
to two years of age. Symptoms that develop are similar to those
of Autism, including intellectual disability and poor growth. It is,
hence, easy to mistakenly diagnose Rett syndrome for Autism, or
symptoms of rett syndrome
Symptoms of Rett syndrome that are similar to
• screaming fits
• panic attacks
• inconsolable crying
• avoidance of eye contact
• lack of social/emotional reciprocity
• general lack of interest
• poor use of nonverbal communication
• delay of linguistic development
• loss of speech.
Symptoms of Rett syndrome that are also present
in cerebral palsy include:
• short stature
• severe dementia
• mild learning disability
• delayed or absent ability to walk
• gait/movement difficulties
• ataxia (unsteady walking)
• abnormally small head
• some forms of spasticity
• wringing of hands
• spasmodic movements of hand or facial muscles
• grinding of teeth.
Symptoms may stabilize for up to a few decades
before complications set in, such as epilepsy
or seizure and spastic paraparesis (spasticity or paralysis of the
Treatment and prognosis of rett syndrome
Currently there is no cure for Rett syndrome.
Treatment of Rett disorder briefly includes increasing the patient’s
communication skills, counseling, modifying social difficulties
and behavioral interventions. Treatment may involve consultations
from speech and language therapists, neuropsychologists, psychologists,
counselors, neurologists, and neuropsychiatrists.
Common drug prescriptions include:
• opioid antagonists.
Common assistive technology used may include wheelchairs or a standing
mortality and rett syndrome
Males with pathogenic MECP2 mutations usually
die during infancy stage from severe encephalopathy, unless they
have an extra X chromosome (often described as Klinefelter’s syndrome),
or have somatic mosaicism. 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
• spontaneous brainstem dysfunction
• respiratory arrest.
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