What Is Angelman Syndrome?
Angelman Syndrome
What is Angelman Syndrome?
Angelman syndrome is a neuro-genetic disorder first described in 1965 by Dr. Harry Angelman. This is where the name of the disorder derived. Dr. Angelman referred to the disorder as ‘Happy Puppet Syndrome’, because the people affected with it generally had a happy, puppet like demeanor, and walked in a stiff, jerky, marionette-like gait. Angelman Syndrome affects about 1 in every 20,000 people. The life span of an individual affected with this syndrome is no different from the average life expectancy. (Angelman Syndrome New Zealand)
How does a person inherit Angelman Syndrome?
The most common cause of Angelman Syndrome is a deletion in chromosome 15. This accounts for about
68% of the occurrences of Angelman Syndrome. As you can see in the picture to the left, section q12 gets deleted from the long arm of chromosome 15. (Angelman Syndrome Foundation Inc)
Though much less common, and only responsible for about 3% of cases, it is possible to have two paternal copies of the chromosome 15 inherited, and no maternal chromosome 15. This is called Paternal Uniparental Disomy. [See picture to the right] Since normally the maternal gene is expressed, and in this case, it is absent, Angelman Syndrome will occur. (Angelman Syndrome Foundation Inc)
If there is a mutation in the gene, and it overlaps with what is called the UBE3A gene and causes a mutationin that as well, Angelman Syndrome will occur if the mutation is on the maternally inheritetd chromosome 15. [See picture to the left] This accounts for about 13% os Angelman Syndrome occurences. (Angelman Syndrome Foundation Inc)
In about 6% of Angelman cases, there is a defect in the imprinting center. The imprinting center is located in the q12 region of chromosome 15, and controls whether the gene for Angelman Syndrome is turned on or off. If the Imprinting Center on the
What is Angelman Syndrome?
Angelman syndrome is a neuro-genetic disorder first described in 1965 by Dr. Harry Angelman. This is where the name of the disorder derived. Dr. Angelman referred to the disorder as ‘Happy Puppet Syndrome’, because the people affected with it generally had a happy, puppet like demeanor, and walked in a stiff, jerky, marionette-like gait. Angelman Syndrome affects about 1 in every 20,000 people. The life span of an individual affected with this syndrome is no different from the average life expectancy. (Angelman Syndrome New Zealand)
How does a person inherit Angelman Syndrome?
The most common cause of Angelman Syndrome is a deletion in chromosome 15. This accounts for about
68% of the occurrences of Angelman Syndrome. As you can see in the picture to the left, section q12 gets deleted from the long arm of chromosome 15. (Angelman Syndrome Foundation Inc)
Though much less common, and only responsible for about 3% of cases, it is possible to have two paternal copies of the chromosome 15 inherited, and no maternal chromosome 15. This is called Paternal Uniparental Disomy. [See picture to the right] Since normally the maternal gene is expressed, and in this case, it is absent, Angelman Syndrome will occur. (Angelman Syndrome Foundation Inc)
If there is a mutation in the gene, and it overlaps with what is called the UBE3A gene and causes a mutationin that as well, Angelman Syndrome will occur if the mutation is on the maternally inheritetd chromosome 15. [See picture to the left] This accounts for about 13% os Angelman Syndrome occurences. (Angelman Syndrome Foundation Inc)
In about 6% of Angelman cases, there is a defect in the imprinting center. The imprinting center is located in the q12 region of chromosome 15, and controls whether the gene for Angelman Syndrome is turned on or off. If the Imprinting Center on the
References: " Foundation for Angelman Syndrome Therapeutics. Foundation for Angelman Syndrome Therapeutics. Web. 17 May 2010. . Images Graph:http://www.angelman.org/media/images/Research%20Cummulative%20Graph%201996-2009.jpg Testing Chart: http://www.angelman.org/media/images/Diagnostic_Testing_For_AS.jpg Kirstie: http://kirstiespage.net/Kirstie98.jpg Chromosome Pictures: http://www.angelman.org/healthcare-professionals/genetic-mechanisms-of-angelman-syndrome/ ----------------------- Kiristie, a patient with Angelman Syndrome Dr. Harry Angelman