People with Parkinson's disease (PD) experience major differences in their symptoms, responses to medications and side effects to treatments. Understanding genetic differences across people with Parkinson's can help uncover important clues about how and why each person's experience with PD differs.

Genetics is the field of science that examines how traits are passed down, or inherited, from parents to children through genes. Genetics has transformed our knowledge of PD and paved the way to many innovations in treatment.

The study of genetics begins with our DNA. Think of our DNA as a cookbook that contains about 23,000 genes, or recipes, that make us who we are. A gene is like a recipe used to build a protein (that help our bodies perform different jobs to function normally). Changes, known as mutations, in our genes can change the recipe — altering the shape and normal function of proteins in our body.

Changes in our genes are mostly harmless, but in some cases, they can affect our risk of getting a disease. Understanding these changes in genes is the basis for the Parkinson's Foundation PD GENEration study, which aims to determine the genetic makeup of 15,000 people with Parkinson's in the U.S.

In addition to genetics, environmental factors and lifestyle choices strongly determine if Parkinson's will develop. Understanding the role of genes and PD can help pave the way to understanding the biological causes of disease and develop novel therapies to treat Parkinson's.