Hi ThumbsUP,
Human genetic disorders are a really interesting field for research but a little difficult to study at the high school level for a science fair project. Fortunately, the extensive DNA databases available on the Internet allow students to ask a lot of good questions that only require their brains and a computer.
Check out this project idea from scibuddies focusing on mutations in the cystic fibrosis gene:
https://www.sciencebuddies.org/science- ... #procedure
For general information about defining the hypothesis and variables in a research project you can read all you need here:
https://www.sciencebuddies.org/science- ... ndex.shtml
There are other respiratory diseases such as asthma that have genetic components. Asthma is a complex and still not completely understood, respiratory ailment with many potential genetic factors. This might offer even more possibilities for research than CF which results from a mutation in a single gene.
I'm sure you will have more questions as you plan and choose a project, and we are here to help and guide you, so keep posting!
Have a great summer,
SciB