Question

Prader-­‐Willi Syndrome occurs when a region of chromosome 15 is deleted from the paternal copy; whereas Angelman Syndrome occurs when this region is deleted from the maternal chromosome. The difference in effect is due to both maternally and paternally imprinted genes being present in this chromosomal region.

1.) Are the maternally imprinted genes associated with Prader-­‐Willi or Angelman? What about the paternally imprinted genes? How do you know?

2. A couple produces two children with Angelman Syndrome. Although people with these syndromes do not usually reproduce, let’s suppose that the oldest child (Pat) grows up and has two children with Prader-­‐Willi Syndrome and the second child (Lynn) grows up and has two children with Angelman Syndrome.

i) Are Pat and Lynn’s parents normal or do they have Prader-­‐Willi or Angelman syndrome? If one of them has a disorder, explain why it is the mother or the father.

Answer 1

The maternally imprinted genes are associated with prader and paternally imprinted genes are associated with angelman In first although every child inherits 2 copies of gene (material , paternal)only paternal copy is in second case although every child inherits 2 copies of gene (material , paternal) only material copy is expressed