User:Meyersg/Sandbox

Angelman Syndrome

Angelman syndrome is a neuro-genetic disorder characterized by

• intellectual and developmental disability
• sleep disturbance
• seizures
• jerky movements (especially hand-flapping)
• frequent laughter or smiling
• usually a happy demeanor

Angelman syndrome is caused by the loss of the normal maternal contribution to a region of chromosome 15, most commonly by deletion of a segment of that chromosome. Other causes include uniparental disomy, translocation, or single gene mutation in that region. A healthy person receives two copies of chromosome 15, one from the mother, the other from the father. However, in the region of the chromosome that is critical for Angelman syndrome, the maternal and paternal contribution express certain genes very differently. This is due to sex-specific epigenetic imprinting; the biochemical mechanism is DNA methylation. In a normal individual, the maternal allele is expressed and the paternal allele is silenced. If the maternal contribution is lost or mutated, the result is Angelman syndrome. (When the paternal contribution is lost, by similar mechanisms, the result is Prader-Willi syndrome.) It should be noted that the methylation test that is performed for Angelman syndrome (a defect in UBE3A) is actually looking for the gene's neighbour SNRPN (which has the opposite pattern of methylation). The Angelman Syndrome Foundation, an organization for development of awareness and reseach is pleased to announce "a new funding opportunity for The Dr. Joseph E. Wagstaff Postdoctoral Research Fellowship. The fellowship was established to promote Angelman syndrome-related research in young investigators, support novel or innovative research initiatives, and to further support and encourage existing Angelman-related research projects."

Links

http://en.wikipedia.org/wiki/Angelman_syndrome http://www.angelman.org/

References

http://en.wikipedia.org/wiki/Angelman_syndrome