Final answer:
Angelman syndrome is caused by genetic issues related to chromosome 15, including a maternal deletion, uniparental disomy, defects in the imprinting center of chromosome 15q, and mutations in the UBE3A gene.
Step-by-step explanation:
Angelman syndrome can result from several different genetic mechanisms involving chromosome 15. Importantly, these mechanisms can disrupt the normal function of the UBE3A gene, which is essential for healthy neurological development.
- A maternal deletion on chromosome 15q refers to the loss of a piece of the long arm of chromosome 15 from the mother. This is one of the most common causes.
- Uniparental disomy for chromosome 15 occurs when a child receives two copies of chromosome 15 from one parent and none from the other. If both are from the father, it can result in Angelman syndrome because the maternal copy, which is typically active due to imprinting, is missing.
- Defects in the imprinting center at chromosome 15q can cause improper gene expression. The maternal copy of UBE3A must be active, and imprinting center defects can silence it.
- A mutation in the gene for E6-AP ubiquitin protein ligase (also referred to as UBE3A), can directly impact its function, leading to the syndrome.
Each of these potential causes disrupts the normal functions linked to the maternal copy of chromosome 15, which leads to Angelman syndrome. Therefore, the correct answer to the question is E All of the above.