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The Face of a Rare Genetic Disease


Karobi Moitra
Department of Biology
Trinity Washington University


This case study is designed to teach basic concepts of genetics by focusing on a rare disease, pseudoxanthoma elasticum (PXE).  Chromosome 16 is the narrator at the beginning of the case and introduces students to genes, chromosomes and mutations. The focus then shifts to the patient and his mother as she finds out about her son’s disease and her subsequent efforts to connect with patient advocacy groups for support. The case concludes with students watching a TED talk given by Sharon Terry, the real-life mother on whom this story is loosely based, so that students can connect on an emotional and human level with someone who has intimate experience as a parent of children with a rare genetic disease. The case is suitable for high school general biology classes, but it can also be used by biology major or non-major undergraduates in a lower-division biology class, or in any lower-division non-major class focused on human disease.


  • Explain the basic structure and function of chromosomes.
  • Explain the relationship between genes, chromosomes, nucleus and the cell.
  • Describe the genetic disease PXE.
  • Explain the basic concepts of genetics.
  • Understand mutations and their role in disease.
  • Learn how to locate information about a particular disease or gene.
  • Read and understand scientific articles and resources.
  • Understand patient advocacy.
  • Connect with the human face of genetic diseases.


Genetics; pseudoxanthoma elasticum; PXE; Sharon Terry; disease; advocacy; genetics; chromosomes; genes; mutation

Topical Areas

Social issues

Educational Level

High school, Undergraduate lower division



Type / Methods

Flipped, Interrupted



Subject Headings

Biology (General)  |  

Date Posted


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

  • Science Didn’t Understand My Kid’s Rare Disease Until I Decided to Study It
    Sharon Terry talks about her children's rare disease PXE and how she decided to study it. This is a personal and true story of a mother who decided to do something to help her kids and other kids suffering from the rare disease PXE. Running time: 14:54 min. Produced by TEDMED, 2016.
  • Mutation
    This video explains the concept of genetic mutations and how they relate to the central dogma of molecular biology. Running time: 7:02 min. Produced by Bozemanscience, 2012.