Origin of a Gene Mutation Causing Early-Onset Alzheimer’s Disease

This activity analyzes a published scientific figure from a study of a family that has a high prevalence of Alzheimer’s disease.

A rare form of familial Alzheimer’s disease, which is caused by a mutation in the presenilin-1 gene (PSEN1), is highly prevalent in some parts of Antioquia, Colombia. To understand the origin of this mutation in these populations, scientists studied the family histories and DNA sequences of people affected by the disease. The figure is a pedigree of a large extended family with a high prevalence of Alzheimer’s. Black circles (female) and black squares (male) indicate individuals affected by the disease. Half-shaded shapes indicate individuals with an uncertain disease status. White shapes indicate unaffected individuals. Shapes with a line through them indicate that the family member is deceased. The “Educator Materials” document includes a captioned figure, background information, graph interpretation, and discussion questions. The “Student Handout” includes a captioned figure and background information.