Cover

Sleuthing for Medical Clues

With 3,000 inheritable diseases, science is homing in on culprit genes

John Nicol September 20 1999
Cover

Sleuthing for Medical Clues

With 3,000 inheritable diseases, science is homing in on culprit genes

John Nicol September 20 1999

Sleuthing for Medical Clues

Cover

The diagnosis for Mary Sterling's aunt was schizophrenia. Sterling's uncle thought he had Parkinson's disease and her brother was told he was manic-depressive. Then, eight years ago, Sterling began suffering from depression, and worried she would end up like her aunt, incapacitated in a constantcare hospital. Or worse, like her uncle and brother who both committed suicide. Four years ago, following the discovery of her grandfathers death certificate, doctors came to believe they were all misdiagnosed. Sterlings grandfather had Huntingtons disease, a late-onset degenerative neurological disorder that leads to dementia. Sterling, a homemaker in Peterborough, Ont., was tested for the Huntingtons gene and found she had it. Doctors said she would gradually lose control of her brain over the next 25 years, and die from complications. The news, however, was totally liberating. “I was no longer ashamed,” says Sterling, now 44. “I can’t help the way I am; it’s in my genes.”

Scientists now believe 3,000 diseases are inherited. They have found the direct gene connection for such maladies as cystic fibrosis, a form of muscular dystrophy, epilepsy, early onset Alzheimer’s, diabetes, some cancers, schizophrenia, hemophilia and sickle cell anemia. With advances in gene research occurring almost daily, medical journals are encouraging doctors to have patients—often at their own expense—trace their medical family tree as far back as possible to enhance the accuracy of diagnosis. It is no longer enough, in many cases, to be able to recite the ages at which your parents or grandparents died, not if you want the best treatment—as women with breast cancer are finding out.

Fiona Webster of London, Ont., saw her two sisters die of breast cancer. But she did not want to undergo radical surgery, such as a precautionary mastectomy, unless she knew she had the mutated gene that increases the risk but is not always inherited by all siblings. A blood test at a private lab showed she didn’t—and led the Ontario government to agree to pay for the test if patients show a compelling case history.

Compelling case histories—or medical pedigrees, as they are called—are “incredibly important, not only in learning what kind of diseases you might be susceptible to, but in tailoring drugs to your particular genetic makeup,” says William Hockett, director of corporate communications with Myriad Genetics Inc., the Salt Lake City firm that developed the breast cancer test. “There are drugs that are appropriate for you if you have no risk of heart disease in your family. There will be more drugs like that in the future.” To create a medical pedigree, families need official death certificates, but they should weigh them against other information, says Stanley Diamond, 66, president of the Jewish Genealogical Society of Montreal. “The problem is, families don’t share their genetic history or medical story. You have to ask those questions the right way, so you don’t give the impression you’re a gossip. This is a tool for future generations.”

family want to their genetic makeup. Four of Mary Sterling’s remaining five siblings have chosen not to undergo the test for Huntington’s (her oldest brother tested negative). Sterling wanted to know for the sake of her two grown children. That desire to know should become more widespread when the Human Genome Project, a multibillion-dollar international effort to map all of the estimated 70,000 to 100,000 genes in the human body, produces its preliminary findings next year. The map will spur on a new generation of targeted drugs. It will also embolden more people to search their past to arm themselves for their medical future.

John Nicol

With 3,000 inheritable diseases, science is homing in on culprit genes