Angelman syndrome is caused by a large deletion of the region of the maternal chromosome that contains UBE3A, or by a DNA sequence change (mutation) in the UBE3A gene inherited from the mother.

For the first time, Colin Farrell has opened up his home and talked in-depth about life with his son James, who has Angelman ...

We each get two copies of every gene - one copy from each of our parents. But what happens when one of these genes has been "turned off", or imprinted, and the remaining gene is defective?