Knowing your family health history can be life-saving. Gather it this Thanksgiving on National Family Health History Day.

With Thanksgiving around the corner, many of us are starting to plan menus, exchange favorite recipes, and prepare our homes for visiting relatives. This much-anticipated holiday also happens to be National Family Health History Day, purposefully designed to encourage us to share our medical histories with gathering family members because that vital information can save lives. Yet it’s surprising how many people don’t take the time to learn their family history. In fact, many of my patients provide only the sketchiest details of the medical histories of blood relatives, which means potentially helpful clues for a diagnosis are often missing. Because so many neurologic conditions run in families, it’s important to let your doctor know if family members have them, in case you develop any symptoms. And since other neurologic disorders have known genetic patterns of inheritance—muscular dystrophies, Huntington’s disease, hereditary neuropathies, for example—your doctor may run genetic screening tests in order to determine if you are at risk. Primary progressive aphasia is also associated with rare gene mutations, and in about 20 to 30 percent of patients, there is a positive family history. In our cover story, actress Kimberly Williams-Paisley describes life for her family after her mother was diagnosed with the disorder, and she offers helpful advice on conversations families should have with someone in the early stages of dementia. This Thanksgiving, let relatives know why sharing their medical histories matter. In “Self-Diagnose Successfully,” we bring you the remarkable story of Jill Viles, a woman with two rare genetic conditions who found explanations for her symptoms by observing patterns in the physical characteristics of relatives and other clues that eventually led to her diagnosis. For a powerful example of the significance of family history, read her story as well as those of others who played detective and helped their doctors determine what was wrong. This Thanksgiving, let your relatives know why sharing their medical histories matter. Gather as many details as possible, including the ages at which your relatives were diagnosed, especially if they were diagnosed earlier than is typical or if multiple family members are affected. Don’t forget about deceased family members. Find out how old they were when they died, what they died of, and if they had any other health problems. Be sure to write everything down and share it with your doctors—even if they don’t ask. Many tools are available to help you record your findings, including My Family Health Portrait (bit.ly/NN-FHP) from the Office of the Surgeon General, an online form that allows you to enter, print, and update your family health history; a family history form (bit.ly/ NN-FHForm) you can download from the March of Dimes; and a downloadable chart from the American Society of Human Genetics (bit.ly/NN-FHQ) . This Thanksgiving, I want to express my appreciation to those who have taken time to write letters. We include a selection of them in this month’s issue, and reading them makes those of us involved in Neurology Now feel so grateful to be part of this publication. Wishing you all a wonderful Thanksgiving!