Rett
SyndromeIntroduction This syndrome is rare and
occurs only 1 in 15,000 to 20,000 girls aged 1 to 18 years (based on studies in
Sweden, the US and Japan). Although this is a genetic abnormality, less than
1% of the cases are inherited conventionally as most occur spontaneously in the
last stages of pregnancy. It is confined almost exclusively to girls. There is
a mutation in the MECP2
gene on the X chromosome, but this in not necessarily immediately obvious.
Course Of Illness It takes usually until the age
of 6 to 18 months to express itself by developmental delay (problems crawling
or late in walking). There is a progressive loss of purposeful use of her hands
and the ability to speak. There are 4 stages that have been defined in the more
severe expression of the disease (see more details under Ref. 2 below). Some of
the symptoms are repetitive movements (moving repeatedly to the mouth) or clapping,
wringing, washing motions. There is muscle weakness causing gait problems. Some
features are similar to autism, but it is a different neurological entity. Diagnosis A child neurologist needs to
be involved in the diagnosis of this condition. The specialist will go over the
symptoms in detail and rule out other conditions. A genetic test will help to
diagnose about 70% to 80% of the cases (MECP2 gene assay), but 20% to 30% will
be due to other genetic abnormalities. At this point there is no reliable therapy
for this rare condition. More research is needed to possibly develop a genetic
vaccine in the future.
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