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.