Question

2.   A family brings their eight year old child in to your medical clinic because they are extremely obese. The family, rather distraught, reports that they have done everything they can to get the child to eat right and exercise, but to no avail. They say that the child has an insatiable appetite and low energy that overwhelms their attempts to manage them – this has been true since birth. With their permission, you take blood samples from the child. These reveal that circulating levels of glucose, free fatty acids, cholesterol, insulin, ghrelin, PYY and leptin are all are at approximately the levels you would might expect for someone of that age and weight. When you interview the child, they verify that they are always hungry.

A.   (6 pts) You suspect that the child has a genetic condition. Suggest which gene you expect might be mutated, and explain in molecular detail why it would lead to the phenotypes shown (excessive appetite, low energy and weight gain).

B.   (4 pts) What experiment would you do next to try to verify your hypothesis? Describe in detail, and explain how this would tell you whether or not you are right.   

Answer 1

Since all the tested parameters like glucose and all are as expected as, the child may be have the genetic condition called Prader- Willi syndrome.

Prader-Willi syndrome is a severe rare genetic disorder which occurs because certain paternal genes that should be expressed are not for one of these reasons:

• Paternal genes on chromosome 15 are missing.
• The child inherited two copies of chromosome 15 from the mother and no chromosome 15 from the father.
• There's some error or defect in paternal genes on chromosome 15.