Well Angelman Syndrome can be difficult to understand as it is a rather rare disorder. Not many people understand it or have even heard of it. (Even medical professionals) Angelman Syndrome occurs once in about every 15,000 babies born. There is currently no cure for this disorder.
When babies are developing, we receive one set of chromosomes from our mother and one set from our father. We get 23 chromosomes from each parent. Angelman Syndrome occurs when there is a change on one of the chromosomes that a person receives from their mother. Scientists have found that in Angelman Syndrome, the change occurs on Chromosome #15.
* The most common form of Angelman Syndrome occurs when there is a section missing or portion deleted on the 15th chromosome received from the mother. This type is called Deletion Positive.
*Another form of Angelman Syndrome occurs when a person gets two Chromosome 15's from their dad and none from mom. (Some speculate that this occurs because mom's is missing and biology tries to fill in the missing pieces) This is a problem because chromosome 15 is the home for a gene named UBE3A. This gene is very important. However the gene is turned off in our father’s copy of chromosome 15, and turned on in our mothers copy. So if you only receive your 15th chromosomes from your dad, you won’t have any UBE3A gene turned on in that area, thus causing Angelman Syndrome. This form of Angelman Syndrome is known as Uniparental Disomy or UPD ( uniparental means deriving from one parent and disomy loosely means getting two of the same copies of a chromosome, so Uniparental Disomy means getting two of the same copies of a chromosome from one parent)
*A third form of Angelman Syndrome is called Imprinting Defect or ID. This form occurs when chromosome 15 is inherited from the father and the mother. However the copy of chromosome 15 inherited from the mother, looks just like the copy received from dad. So it is "imprinted" improperly. This imprinting defect leads to Angelman Syndrome.
*Finally another form of Angelman Syndrome can occur when there is a mutation on the 15th chromosome inherited from the mother. This rearrangement takes many forms, but can ultimately also lead to Angelman Syndrome Disorder.
Angelman syndrome is characterized by;
• Severe learning difficulties
• Characteristic facial features (The facial features are subtle and include a wide, smiling mouth, prominent chin, and deep set eyes)
• A happy, sociable demeanor
• There are usually delays in development
• They do not speak, however some may develop small vocabularies
• They are often characterized as displaying jerky movements
• Frequent and sometimes inappropriate laughter
• A love of water or plastic (crinkly items)
• And sleeping difficulties or disorders
This is of course just a general short explanation of Angelman Syndrome. As the Resource Specialist for the Angelman Syndrome Foundation, I would be happy to answer any further questions you may have. We can be reached at 1-800-432-6435, firstname.lastname@example.org or via our website at www.angelman.org
Williams M.D., C., Peters Ph.D, S., & Calculator Ph.D, S. (2009). Fact about angelman syndrome. Retrieved from http://www.angelman.org/_angelman/assets… about as 2009 3-19-10.pdf