Angelman
SyndromeIntroduction Angelman syndrome is found
in 1 of 10,000 births. It is a micro deletion syndrome affecting
chromosome 15 involves a process of genomic imprinting where a sequence
of genes from the maternal chromosome are silencing the critical corresponding
genes from the fathers chromosome so that the end result is a defective chromosomal
gene sequence in that region. This interferes with the fetal development and results
in a series of changes in the person born with this chromosomal abnormality. The
mirror image micro deletion syndrome of Angelman Syndrome is the Prader Willi
syndrome, where the deletion of 15q11-q13 is paternally derived. Signs
and symptoms
In
the case of Angelman syndrome there is a small head (microcephaly) and the individuals
have mental retardation. Here is an image of a child
with Angelman syndrome. Their movements are puppet-like, but not
truly ataxic. A person with Angelman syndrome will frequently burst out in unprovoked
laughter. Seizures are also common and EEG recordings between seizures will show
a characteristic pattern of bifrontal runs of notched slow waves. Sleep EEG’s
show slow and sharp waves. The brain has normally folded surfaces (normal gyral
development), but a mildly thinned grey matter layer (mild cerebral atrophy).
The cerebellum shows marked atrophy. Treatment As
this is a genetic syndrome, there is no treatment available. These individuals
will need to live in a supportive environment and often end up in a specialized
home that is equipped to deal with these patients.
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