Daily questions for Session 12

  1. You may need to study next week's topic before you answer this question. Some tumours are heritable whereas others are not. Tumours  are caused by mutations. In what type of cell would a mutation that resulted in a heritable tumour occur? Why are only some tumours heritable?
  2. Daniel is 16 months old who has phenylketonuria (PKU). PKU is caused a a recessive condition that results in a mutated amino acid sequence of an enzyme called phenylalanine hydroxylase. Without this enzyme, the body cannot catabolise phenylalanine in the body, so it accumulates has a toxic effect. In the body, phenylalanine is broken down to another chemical called tyrosine that is used to make several chemicals including adrenaline. If phenylalanine cannot be broken down, there is no tyrosine and therefore no adrenaline. The chance of future children inheriting PKU is of great concern to Daniel’s parents (both unaffected) and they are hesitant to have another child – so they also seek genetic counselling at the clinic.What advice would you give them if you are doing the genetic counselling?
  3. As part of a clinical placement you are visiting a teenager who has had continuing respiratory infections since birth due to cystic fibrosis. The boy’s problems are not limited to his respiratory system. His body weight is very low, and he has a long history of suffering from diarrhea. The boy’s parents meet you at the door with their daughter. The daughter has been tested and found to have cystic fibrosis but her clinical symptoms are far less severe than those of her brother. How could this occur?
  4. Some tumours are heritable whereas others are not. Tumours  are caused by mutations. In what type of cell would a mutation that resulted in a heritable tumour occur? Why are only some tumours heritable?