Genetic gamble

A cruel disease that follows a family from generation to generation now poses an agonizing question for its youngest members.


It was just a twitch - a muscle that danced wildly on the side of her left thigh while she sat in front of the television one afternoon.

But, as Toi Mason recalls, the tiny shudder struck her with a fear so intense that she prayed for it to be still.

"I was sitting on the couch when I started to feel it move," said Toi, 21, a senior at Temple University in Philadelphia. "All I could think of was, `Oh no, please, God, don't let this be it. Please don't let this happen to me now.' "

Ever since she was a teenager, Toi has been living with the terrifying possibility that she will succumb to Huntington's disease: a rare, neurodegenerative illness that wages a slow and gruesome assault on the body and mind. The disease is fatal, and there is no cure.

Huntington's has stricken members of at least eight generations of Toi's family, which is deeply rooted in Anne Arundel County. The latest victim is her father, Troy, who was diagnosed with it at age 21. Since then, he has lost his ability to control movements, speak, eat and walk.

Because she has a parent who has Huntington's, Toi faces frightening odds: There is a 50-50 chance that she carries the gene that causes the disease. If she does carry the gene, it is statistically certain that she will develop Huntington's.

Toi could take a fairly simple test to determine if she has the gene, but she has chosen not to. Though that might seem surprising, many of the hundreds of thousands of people haunted by the specter of hereditary diseases choose not to know the future.

The number of people who face this choice is growing as scientists unravel the genetic basis of more diseases. Not all tests provide certainty. For some hereditary cancers, for example, a test can give only a percentage chance of developing the disease.

Knowing what lies ahead can help people plan their health care and make major life decisions, including whether to marry and have children. But it also can be psychologically crushing.

Nancy Wexler, who heads the Hereditary Disease Foundation, has said genetic testing can deprive people of the hope that they will beat the odds.

"Denial and hope," she said in a medical paper, "are the twin mainstays of survival in impossible circumstances."

Toi agonized over whether to be tested before deciding against it. If she learned she has the gene, she said, that knowledge would put the brakes on her life.

"The thing is, I've got this life plan that I want to live, and I don't want Huntington's to hinder it," said Toi, who aspires to be an attorney. "Right now, I'm too young to have Huntington's - I'm too young to even have a cold."

Subtle start

Huntington's is rare: About 30,000 have it, according to the foundation, and 150,000 are at risk. The disease begins with shadowy symptoms - a slight tic, the tapping of fingers or moderate depression. Over time, it causes more pronounced movements called "chorea," which make the body jolt and shudder like a puppet on a string.

Among the Masons' early ancestors, Huntington's was called the "Suffer Dance" for the involuntary movements it caused.

Some of their relatives were sent to Crownsville Hospital Center, where they were misdiagnosed as schizophrenic. Others lived at home, among family members accustomed to the symptoms.

It was the Masons' extended family, most of whom still reside outside Annapolis, together with a large family in Western Maryland, who provided Johns Hopkins Medical Institutions with the family tree needed to search for the gene.

Enlisting the help of two sleuthing social workers, Hopkins researchers traced Huntington's back through eight generations in the Masons. That medical family tree, along with blood samples from both afflicted and non-afflicted family members, helped researchers at Massachusetts General Hospital narrow in on the location of the gene that causes Huntington's. The final discovery was made in 1993, and with it came a predictive test.

As the Huntington's researchers were nearing their breakthrough, the future parents of Toi Mason were concluding a courtship that began on a double date arranged by a mutual friend.

"It was definitely his looks that got me at first," said Rosemary of her husband, a star football player at Annapolis High School. "But he was also just such a sweet young man and such a charming person."

When they married three years later, in 1984, Rosemary and Troy didn't give any thought to their family history, even though it had claimed lives in both their families.

"I knew my mother had what we called the Suffer Dance, but she died young of cancer," said Rosemary. "And I suspected that Troy's mother might have had it, but the doctors said she had Parkinson's disease."

The couple had two children and lived in a rowhouse in East Baltimore. They enjoyed barbecues, going to the movies, and hosting huge parties for relatives and friends.

But in 1988, the same year Troy's mother died, he developed a noticeable twitch in his left arm. Something inside Rosemary clicked.

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