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Targeted Genome Modification of Disease


Andrea M. Henle
Biology Department
Carthage College


This interrupted case study tells the story of a woman with cystic fibrosis and her husband. The couple is presented with an opportunity to potentially fix the woman's disease-causing gene using CRISPR. Students follow the couple as they face decisions about her health and lifespan, as well as the health of any children they might have. The case is used to teach students about the genetics of cystic fibrosis, genome editing using CRISPR, and how to use CRISPR in the clinic or laboratory. The case also provides an opportunity for a discussion of bioethics, specifically pertaining to genome editing, "designer babies," and how genome editing should be paid for when it is used in humans. As such, it is appropriate for use with non-major students although originally designed for undergraduate biology majors in a sophomore-level cell and molecular biology course.  It could be used in introductory biology courses, and it would also be suitable for upper-level biology courses, particularly if the instructor places more emphasis on the final part of the case study, which is focused on CRISPR design.


  • Investigate the molecular cause of a genetic disease.
  • Describe the structural and functional components of the CRISPR technology and how DNA repair mechanisms are employed by this new genome editing technology.
  • Apply scientific knowledge to a discussion of bioethics.
  • Gain practice working with and manipulating gene sequences in order to understand the difference between DNA, mRNA, cDNA, and protein sequences.


CRISPR; Cas9; CRISPR-Cas9; CRISPR-Cas; cystic fibrosis; genetic modification; editing; bioethics; enzymes; DNA; RNA; designer baby

Topical Areas

Ethics, Regulatory issues

Educational Level

High school, Undergraduate lower division, Undergraduate upper division



Type / Methods

Dilemma/Decision, Directed, Discussion, Flipped, Interrupted



Subject Headings

Biology (General)  |   Biochemistry  |   Biotechnology  |   Cell Biology  |   Genetics / Heredity  |   Medicine (General)  |   Molecular Biology  |   Nursing  |  

Date Posted


Teaching Notes

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The following video(s) are recommended for use in association with this case study.

  • Genome Editing with CRISPR-Cas9
    A brief overview of the CRISPR-Cas9 method for genome editing with excellent animations. Running time: 4:12 min. Produced by the McGovern Institute, 2014.
  • How CRISPR Lets You Edit DNA
    This TED-Ed animation by the author of this case study provides an introduction to CRISPR. Running time: 5:29 min. Produced by Andrea M. Henle and Adam Wells, 2019.


J Brown

Laguna Hills, CA
The article by Hwang et al. appears to be for purchase only, so this isn't usable for students who attend an institution which doesn't purchase access. AUTHOR'S REPLY: The case study can still be used without the preparation section. Alternatively, you can assign the preparation section to students with just the open-access Doudna 2013 article that is typically assigned ( In that case, just omit questions 4 and 5 from the homework assignment that are specific to the Hwang et al. article. All of the other homework questions can be answered through reading the Doudna 2013 article.