lunes, 30 de abril de 2012

Genetic testing and disease: Would you want to know? –

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Genetic testing and disease: Would you want to know? –

Genetic testing and disease: Would you want to know?

CHAPEL HILL, N.C – Kristen Powers finishes packing her lunch and opens the kitchen door to leave for high school with her brother, Nate, in tow.

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"I drive but always let him pick the music," she says, smiling.
He gives her a gentle nudge and they set off to the car.
Nothing like having a kid brother behind you, especially when you are embarking on a courageous journey. Kristen, 18, is having blood work done May 18 to find out whether she inherited the defective gene for Huntington's disease, a fatal, neurodegenerative disorder that can debilitate victims as early as their mid-30s. The siblings have a 50-50 chance of developing the rare disease, which claimed their mother's life last year at age 45.
Nate, 16, doesn't know whether he'll follow his sister's lead. Only people 18 or older can be tested, unless they're exhibiting symptoms, because a positive result can be shattering news. There's also no cure. Huntington's is devastating on so many levels: People lose coordination, developing wild jerky movements; they suffer behavioral changes, often becoming depressed and psychotic; and in the end, they develop dementia and require total care. One of their last images of their mother was in a wheelchair in a nursing home.

Cast Your Vote

Nate "has been amazingly supportive of my wanting to get tested," Kristen says. "He is interested in the whole process, but he's been hesitant over the years to commit to testing, while I've known since I was 15 that I wanted to do this."

Sara D. Davis, for USA TODAY

Kristen Powers, 18, with her brother Nate, 15, stepmom Betsy Saul and father, Ed, at their home in Chapel Hill, North Carolina. 

"Know thyself" has taken on a scientific meaning for a growing number of people who, like Kristen, want a crystal ball to look into their DNA. Ever since the Human Genome Project identified the 20,000 to 25,000 genes in 2003, researchers have continued to identify the ones that play roles in diseases, from Alzheimer's to type 2 diabetes to certain types of cancer. Though lifestyle and environment are big pieces of the puzzle, consider this: Genetic tests could become part of standard care for everyone and revolutionize the way medicine is practiced, proponents say.

Gone would be the days of waiting to develop a disease. People would know about diseases they are at risk for and could change their living habits or consider treatments. Opponents warn about the potential for invasion of privacy — threatening employment and insurance — and the possibility that people equipped with the knowledge of their genetic makeup might make risky and unhealthy decisions.

What about insurance?

Ed Powers backs his daughter Kristen’s decision to find out whether she inherited the gene for Huntington’s disease, but he also wonders how a positive result might affect his family’s health insurance.

“I hope ObamaCare takes care of us,” he says. The Supreme Court is expected to rule on the fate of the Affordable Care Act in June.

About 30 million Americans live with rare diseases, many of them chronic. People afflicted with these diseases often have difficulty obtaining coverage, or the policies are cost-prohibitive. The health care law created the pre-existing condition insurance plan (PCIP) for Americans denied coverage by private insurance companies for health reasons. PCIP is currently in effect.

If the law is upheld, all Americans, regardless of health status, will have access to insurance by 2014 through an employer or in the marketplace, says the Department of Health and Human Services. Insurers will be prohibited from charging more or denying coverage to anyone. The law also eliminates annual and lifetime insurance caps. 

Kristen has had counseling at the University of North Carolina to prepare her for dealing with her testing news, and she copes with stress by walking with her rescue dog, Jake. "Walking is critical for me," she says. She will return to the campus at the end of May with her father, Ed Powers, to get the results.

"She's always wanted to take matters into her own hands," her father says. "She's constantly asking what we can do to make things better. I am her biggest backer and want to be there for her every step of the way during this."

Leaning on social media
Kristen leans on her kitchen table and explains in a quiet, clear voice that she is ready to handle the news and has no plans to keep it secret.

"I started out trying to find answers on the Internet about Huntington's disease," she says, "but I quickly became very disappointed. There's not a good video or an advocate for it, like Michael J. Fox is for Parkinson's disease."

She has raised $17,580 on the website and hired a video crew to make a documentary about the emotional and medical aspects of testing on her and her family. "Social media can be a real unifier. There's not much out there yet for young people on Huntington's. I want to change that."

Her mother, Nicola Powers, was diagnosed in 2003 after struggling with symptoms for several years. "I remember watching her stumble and walk like a drunk person at times," Kristen says. "That was before we knew what was wrong with her. She was really struggling. It was very scary."

Nicola Powers didn't know the disease ran in her family. She grew apart from her biological father after her parents divorced. Once she looked into his medical history because of her symptoms, she discovered he had Huntington's. 

Kristen doesn't want the gene to be passed on again. She says she won't have children if she tests positive: "I can be candid with potential partners and be responsible," she says.

Genetic counselors warn about the emotional impact of testing on the person and family.

"Some people like to plan everything out," says Brenda Finucane, president of the National Society of Genetic Counselors. "They think the information is empowering, while some people want to see how life plays out."
Robert Green has found that most people will not seek out risk information about late-onset Alzheimer's disease if they're not psychologically prepared to handle it.

But "it turns out many people handle this kind of information quite well," says Green, associate director for research in genetics at Brigham and Women's Hospital in Boston. "Some changed their wills, and some made lifestyle changes. Taking these tests is all about actionability."

Timing can be tricky, though. Kristen's father and stepmother, Betsy Banks Saul, suggested she hold off until she has a support system at college. "She's a very intelligent, strong young woman and we trust her, but we wish we could be nearby to support her," Betsy says.

After high school graduation in June, she will attend Stanford, in California — far from her farm, family and friends. Kristen listened to her parents' concerns and considered putting off testing, "but I am a type A person who has always craved getting information. I want to know."

Not all tests are equal
Her test will look for the single gene that causes Huntington's, but most diseases have a more complicated genetic profile. A growing number of tests look at multiple genes that might increase or decrease a person's risk for developing thousands of diseases. Companies market the tests for as little as $100 on the Internet and don't require a physician's signature. But those kinds of results are not always reliable, says Ardis Dee Hoven, former chair of the American Medical Association.

"In the absence of a medical professional, a patient might have difficulty interpreting the test and make decisions that are not healthy decisions," Hoven says.

For instance, someone who tests negative for BRCA1 and BRCA2 — genes that put people at a higher risk for developing certain breast and ovarian cancers — might not know there are other risk factors. Unless the patient has a physician guiding her, Hoven says, she might think she's home-free and skip routine screening tests.

David Agus, author of the new book TheEnd of Illness, says that's why the company he co-founded, Navigenics, requires customers to get a signature from their doctors before being tested. Navigenics also offers genetic counseling as part of the $300-$400 fee. 

"Genetics are a small piece of the puzzle, but they're a very important piece," says Agus, head of the Center for Applied Molecular Medicine at the University of Southern California

A cancer specialist, Agus discovered he has an above-average risk for cardiovascular disease and a slightly lower-than-average risk for colon cancer. His doctor put him on a statin to help prevent heart disease, and, he says, "my kids took it upon themselves to keep me away from french fries." He also had a colonoscopy at age 43, earlier than medical standards call for, and had a polyp removed. "Could my polyp have turned into cancer? Who knows? But why should I wait for that to happen? Unless our country can focus on prevention, which testing is all about, our health care costs will be completely out of control." 

A study of 1,200 patients that was presented in March at an American College of Cardiology meeting found that those who were told they had a gene linked to heart disease improved their adherence to statin therapy by 13% compared with those who had not been tested for the gene.

"I could see how testing could become embedded in how we treat our patients," Hoven says. "It's always better to prevent disease than to treat it, and quality of life is so much better for people."

How accessibility could change
Since the human genome was unraveled a dozen years ago, genetic testing has been cost-prohibitive for the average person. The promise was that this breakthrough would lead to a better understanding of myriad diseases and, ultimately, individualized treatments. Whole genome testing studies the interaction of our 20,000 to 25,000 genes with one another and with a person's environment. The $10,000 price tag, though, is expected to drop to $1,000 within the decade. When the tests become mainstream, doctors could face a dilemma. 

A study in March reports that 10 of 16 specialists (62%) favored telling a patient he carried the gene for Huntington's if the finding was incidental to why the test was ordered. The study noted that the specialists unanimously agreed on disclosing 21 of 99 commonly ordered genetic conditions for adults, and "multiple expert panels" might be needed to agree on what to tell patients.

"This is one of the toughest issues facing the rollout of clinical sequencing (whole genome sequencing)," Green says. He adds that after the study, he co-chaired a forum March 28 of the American College of Medical Genetics to discuss how to form a consensus.

That's a non-issue for Kristen. She knows she will get an answer. One of her hardest decisions has been picking who will be in the room when she gets her results. She knows she wants the videographers taping. At first she didn't want her father to be there, but she relented when he asked her to reconsider.

"I know I can take the news," she says, "Knowledge is power. But I didn't think I could get a positive result and then watch my father cry. I've never seen him cry before."

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