Parkinson's Clinical Trial Companion Navigating Clinical Trials - Page 32

Parkinson’s Genetics 101 Genes are the material of heredity, p assed down through the generations from parents to children. T hese inherited bits of DNA make us who we are — visible features such as eye color, as well as ones that can’t be seen, i ncluding an individual’s risk of disease. W hile we all have the same types of genes, s ome people have a change in gene sequence; these are called genetic mutations. Everyone gets two copies of each gene, one from each parent. In some cases, a mutation in just one of those copies is enough to raise the risk of Parkinson’s disease (PD). These are called “dominant” mutations. In other cases, PD only develops if both copies are affected — these are called “recessive” mutations. Some mutations cause PD in younger patients, but others lead to PD at the typical age. And some mutations may affect how a person’s PD progresses or how symptoms respond to medications. The science is complicated, but your doctor and a genetic counselor (see “What is a Genetic Counselor?” pg. 37) can help break it down for you. 30 Scientists long thought Parkinson’s had no genetic connection. Most people with PD do not have a family history of the disease. But in the past two decades, researchers have identified a number of genetic mutations that play a role in Parkinson’s. These discoveries are important because they give us a starting point from which to study disease biology and to design treatments to prevent or stop progression. While we still have much to learn about Parkinson’s genetics, there are some things to know now. Navigating Clinical Trials: A Guide for Parkinson’s Patients and Families