Q. What exactly is a medical family tree and is it worth doing?

A medical family tree is like the ones genealogists prepare, but it also includes all the maladies suffered by members of the family. A medical tree can reveal patterns and help a family choose medical tests.Many of the causes of our illnesses are inherited from our ancestors. Almost a third of known diseases have family links. These include colon cancer, heart disease, alcoholism and high blood pressure.The following is important information about each family member: living and dead: that should be included in a health history.1. Birth and death dates.2. Cause of death.3. All medical conditions with dates and outcomes. Include anything outside the norm, not just serious diseases. Don't forget problems such as allergies, vision and hearing difficulties.4. Birth defects.5. Mental health problems.6. Lifestyle description. This would include information about smoking, drinking, diet, obesity and exercise.7. Racial and ethnic background. Some medical conditions are more common in certain groups of people.Q. Is genetic testing dangerous?I don't know if I would call it dangerous, but it can be upsetting if you find a medical problem in your DNA.DNA, or deoxyribonucleic acid, is in the genes you get from your parents. DNA guides the cells in your body. If your DNA contains a mutation, you could develop a medical condition.A test can reveal mutations that raise the risk of developing a disease. Positive results for certain diseases can induce people to take preventive action, such as surgical removal of endangered organs.Genetic testing should be viewed as a fallible tool. A positive result for a mutation doesn't mean you'll get a disease. And a negative result doesn't mean you are immune.Multiple mutations can cause a disease. Multiple genes can be responsible for a single disease. There are gene changes that develop without any link to your ancestors; they happen because you smoke or get too much sun or sometimes for no known reason.Q. Can you diagnose disease by looking at someone's nails?The condition of your nails can tell medical professionals a lot about your health. Most doctors include a nail examination during a physical checkup. Common problems that produce symptoms in the nails are the following:• White nails: liver diseases• Thick, pitted nails: psoriasis• Nails that are half pink/half white: kidney diseases• Red nail beds: heart conditions• Thick, yellow nails: lung diseases• Pale or concave nail beds: anemia• Light yellow nails, with a slight blush at the base: diabetesNail growth is affected by disease, hormone imbalance, and the aging process, itself. Many seniors suffer from nail problems because nails thicken as we age. Seniors also have greater circulation difficulties, and we use more medications; both of these impact nails.If you would like to read more columns, you can order a copy of "How to be a Healthy Geezer" at

www.healthygeezer.com.The Times News, Inc., and affiliates (TIMES NEWS) do not endorse or recommend any medical products, processes, or services or provide medical advice. The views of the author do not necessarily state or reflect those of the TIMES NEWS. The article content is not intended as a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician, or other qualified health provider with any questions you may have regarding a medical condition.