AQA Biology A2 Unit 5 - Gene tech question

I noticed that in a lot of the textbooks they mention cystic fibrosis and severe combined immunodeficiency. I'm kinda confused though because in the spec all it says about gene therapy is "the use of gene therapy to supplement defective genes". Are we expected to know about cystic fibrosis because the spec makes literally no mention of it???

They won't directly ask you a question on cystic fibrosis, however if you use cystic fibrosis as an example in the essay at the end you'll receive extra credit