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What's Wrong with Our Son?

An Integrative Case Study in Genetics, Molecular and Cell Biology


Julia A. Emerson
Department of Biology
Amherst College
Andrew E. Emerson

Five Foot Studios


In this interrupted case study, students examine the fundamental connections between genotype, 3-D protein structure and phenotype by exploring possible underlying causes of the human genetic disorder, spondyloepiphyseal dysplasia congenita (SEDC), a type of dwarfism. Students integrate their knowledge of concepts in genetics, molecular and cell biology with information specific to SEDC, which they obtain from online biology sites and databases. The affected gene in SEDC encodes the polypeptide chains that make up type II collagen, which functions primarily in the extracellular matrix of cartilage tissue. Students examine the impact of specific gene mutations on the 3-D structure of a protein, the protein secretory pathway of cells, the importance of the extracellular matrix in maintaining tissue integrity and function, and basic aspects of how bones grow longer in mammals. Students also have the opportunity to discuss the pros and cons of genetic counseling for individuals who are living with genetic disorders. The case is designed for a sophomore-level course in genetics, molecular and cell biology. It could also be modified for cell biology or first-year introductory biology courses.


  • Explore on-line biomedical sites and databases to learn about a human genetic disorder (one type of dwarfism).
  • Draw simple family pedigrees and understand how new mutations come about.
  • Learn about collagens and their importance in maintaining integrity of the extracellular matrix of mammals.
  • Increase understanding of the protein synthesis and secretory pathway, using collagen as an example.
  • Apply knowledge of amino acid and protein structure to understand the links between gene mutations, 3-D protein structure and clinical phenotypes.
  • Discuss what it might be like to live with this genetic disorder and the value of genetic counseling.


Spondyloepiphyseal dysplasia congenital; SEDC; SED; SDC; dwarfism; epiphyseal growth plates; gene; allele; genotype; phenotype; autosomal dominant; recessive inheritance; pedigree; mutation; collagen; DNA; protein structure; genetic counseling;

Topical Areas


Educational Level

Undergraduate lower division, Undergraduate upper division



Type / Methods

Dilemma/Decision, Directed, Interrupted



Subject Headings

Cell Biology  |   Genetics / Heredity  |   Medicine (General)  |   Molecular Biology  |   Bioinformatics  |  

Date Posted


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