Disability and education - Essay Example

The most eminent AS characteristics include, Seizures, which start showing at the age of 2 to 3 years affecting approximately 80% of all children experiencing AS (Clayton-Smith, 2010). Speech impairment, which ranges from little to no words at advanced stages. Consequently, this forces some victims end up using gestures or picture communication systems while conversing with other people (Clayton-Smith, 2010). In adult stage, people experiencing AS usually develop facial distinct features commonly described as “coarse” Victims of this disorder exhibit hyperactivity and in some cases stiff limbs, which become hindrance to their mobility.

Sleep disorder. Imbalance state especially when one is walking or trying to undertake certain personal tasks. Exuberant behavior coupled with happy demeanor (Dan, 2009). b. Incidence/prevalence Studies so far contacted cite AS is among the rarest diseases not only in US but also globally. Its prevalence is about one person in every population ranging from 12,000 to 20,000 people (Panayiotopoulos, 2010). However, this prevalence only represents estimates because the disorder’s exact data up to date is still unknown. . d.

Etiology Angelman Syndrome (AS) is a disorder normally caused by the anomalous functioning of the UBE3A gene, located on chromosome number 15. A child inherits a copy of the gene from each parent. The two copies are active in nearly all the body tissues but only the gene replica attained from the mother is active in the brain. The disorder occurs due to four major genetic mechanisms, which include chromosome 15q11 –q13 deletion. It involves deletion of a very small piece of DNA missing from the chromosome.

The number of Angelman Disorder due to deletion range from 65% to 75% and the risk of recurrence rate being 1 %(Cassidy & Allanson, 2011). The second mechanism is the paternal uniparental disomy (UPD) whereby the patient posses two copies of the chromosome 15 and no copy of the same chromosome from the mother. The number of AS cases due to UPD accounts for 3 to 5 %of all reported cases where chances of recurrence is below 1 percent. The third mechanism encompasses Imprinting Center (IC) mutations, which account for about 7% to 9% of the reported AS cases and has a significant recurrence of 50%.

The IC works like a switch. It turns on the UBE3A gene copy inherited from the mother while at the same time turns off the copy of the gene inherited from the father in the central nervous system tissues. The fourth mechanism is the UBE3A mutations. It occurs irregularly in patients suffering from it and accounts for an approximately 6% to 20% of the total AS cases. Normally, the risk of recurrence is less than 1% but increases to 50% if the mother of the affected person has the UBE3A mutation on her inherited paternal chromosome 15.

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