Family history can hint at how the future will shape up

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By Carolyn Butler
Tuesday, October 27, 2009

I used to rebel against the idea that we all become our mothers. But lately I find it awfully hard to deny. When four generations sat around my dinner table a few weeks back, I saw not only that am I the spitting image of both my mom and my grandmother, but also that this inheritance has also turned up everywhere from my 3-year-old's hazel eyes to my 6-month-old's dimples. We all have the same body type, sensitive skin and dark circles under our eyes -- even the kids! -- and left-handedness clearly runs in the family as well.

But other links were just as striking: None of the women at the dinner table sleeps well. We like to read. My older son and I have ferocious tempers, while my youngest appears to be more laid-back, like his grandmother. My mom's legacy is also evident in certain parenting tics, such as my completely instinctive, almost involuntary use of her most terrifying threat: "If I have to come in there, you will be sorry."

As charming as most of these shared traits are, what about the less obvious ones? In other words, I wonder how much of my body's future I can see in my grandmother, who is still in excellent health at 91 -- and continues to tool around New York City by bus -- despite her high cholesterol and arthritis and the fact that she recently had a fall and now uses a cane. Am I destined to end up overweight like everyone else in the family, and will it cause other problems? Will I live as long and as well as my grandma has? Can I stave off gray hair well into my 70s, like she did? Do I need to worry about my cholesterol -- and maybe heart disease? And why do my joints hurt on cold mornings, even though I'm only 34?

While it may be impossible to make direct links between my ailments and theirs, knowing what they've been through may help me stay healthier in the years ahead.

Science has clearly shown that there's an underlying genetic susceptibility to many of the most common chronic diseases, including heart disease, diabetes, cancer, obesity and mental illness. And yet very few conditions are caused by a single gene or genetic mutation.

"In most cases, there's not just one gene that controls a particular trait; it's a combination of lots of genes that each have a small effect, and we don't have any good way to predict how that complex mixture of genetics is going to play out, especially when you add in environmental factors," says Mark Boguski, an associate professor of pathology at Harvard Medical School. "There's a saying: 'There's your DNA, and then there's what you do about it.' It's not destiny; it's just a matter of probability."

And it's more complicated than most folks realize, says certified genetic counselor Carrie Zabel, assistant director of the Eisenberg Genomics Education Program at the Mayo Clinic in Rochester, Minn.

"We get a lot of patients who talk about family history in our clinic and say, 'Well, I guess I know what I'm going to die from,' " she says, "but even with some of the single-gene conditions -- the breast cancer gene, for instance -- people who are identified to have it don't always go on to develop the condition. The risk is up to 80 percent, but at least 20 percent of those people don't ever develop breast cancer. We don't know exactly why they don't, if it's environmental or the interactions of other genes. The genetic test or family history gives us some clues, but it's not the whole story."

Still, it's essential to know your family history and to share it with your doctors, in order to raise the right red flags -- and to start modifying your lifestyle choices and behaviors accordingly, whether that means changing your diet, exercising more or getting specific screening tests more often.

Despite the increasing number of technologically advanced genetic tests out there, sitting down and simply interviewing your parents, siblings, grandparents and other relatives remains the best place to start. "Family history is still the cheapest, most accessible, most time-tested way to get a rough estimate of the genetic component of disease risk," says Rear Adm. Robert C. Williams, the acting deputy surgeon general.

Even so, a Centers for Disease Control and Prevention survey found that while 96 percent of Americans believe that family history is important, just one-third have ever attempted to collect and record their own.

If you're looking for an excuse to get started, Thanksgiving is National Family History Day: a great opportunity to hash out the particulars of Aunt Mary's diabetes or Grandpa's prostate cancer while gorging on turkey and stuffing. The surgeon general's office also offers "My Family Health Portrait," a free online tool that allows you to record your family history and put it into a format useful for medical providers. Among the basic questions it asks: What diseases or medical conditions do you, your parents, grandparents, siblings, aunts and uncles have, and at what age they were diagnosed? (The earlier the onset, the more likely there is to be a genetic tie.)

Mayo's Zabel also recommends tracking the number of relatives with the same, or a related, condition; whether people smoked or engaged in other risk factors that may have contributed to the development of a disease such as lung cancer; and whether any condition appears to have been passed on in multiple generations.

I, for one, intend to collect this information as part of an ongoing quest to refocus on health and wellness, which I'll be documenting in this column. The first revelation? I've realized that I'd actually be lucky to turn into my mother, a 62-year-old grandparent with few medical concerns, luminous skin and boundless energy. Now if only I could stop spouting her cliches . . . .

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