[tt] Los Angeles Times: The conundrum of genetic testing

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The conundrum of genetic testing
http://www.latimes.com/news/nationworld/nation/la-sci-gaucher19sep19,0,5667596,print.story?coll=la-home-nation
[Thanks to Sarah for this.]
7.9.17

Screenings offer knowledge, not necessarily wisdom, experts say. A
study finds Gaucher disease counseling cut the number of abortions.

By Karen Kaplan
Los Angeles Times Staff Writer

Thirty-five years after genetic screening was first used to identify
babies at risk of being born with debilitating diseases, a new study
of a potentially serious but treatable illness among Ashkenazi Jews
questions whether such testing has gone too far.
One-quarter of fetuses found to have Gaucher disease were aborted
over an eight-year period, even though half of all children with the
metabolic disorder will never experience any symptoms, such as pain,
organ enlargement and anemia. The rest can lead normal lives with
treatment.
Importantly, the researchers found that among couples who met with a
Gaucher expert and learned that the disease was treatable, only 8%
chose to terminate their pregnancies. All of the couples who didn't
have those meetings opted for abortion.
The disparity underscores what some experts say is a flaw in genetic
testing: It provides a bounty of knowledge that is not necessarily
accompanied by wisdom.
The study, published today in the Journal of the American Medical
Assn., tracked nearly 29,000 Israelis who opted to be screened for
mutations in their DNA that could lead to Gaucher disease in their
children if they inherit faulty genes from both parents.
Similar screening tests are offered to other specific ethnic groups
predisposed to disorders, such as albinism and congenital deafness.
Dr. William R. Wilcox, who treats Gaucher patients at the Medical
Genetics Institute at Cedars-Sinai Medical Center in Los Angeles and
was not involved in the study, said that given the ambiguity
inherent in some genetic tests, they should not be given for
diseases that are imminently treatable.
"Personally, that horrifies me," he said. "Why is it there? Because
we can do it. But just because we can doesn't mean we should."
Others say abandoning the genetic test would unfairly deny couples
genetic information about their offspring.
"It's an opportunity to gain information which some people might
want," said Karen Grinzaid, a genetic counselor at Emory University
in Atlanta who coordinates care for Gaucher patients. "It's their
decision about what they want to do with that information."
As gene-hunters find more DNA mutations associated with particular
diseases, the number of people who will be left grappling with
ambiguous results is likely to grow, experts said.
"This is just the tip of the iceberg," Wilcox said. "There will be a
time when we have the ability to screen for thousands of diseases in
one blood spot. What are you going to terminate for?"
First successThe proliferation of screening tests was largely driven
by the success of carrier screening for Tay-Sachs disease, another
condition with high incidence among Ashkenazi Jews, or those of
Eastern European descent.
Children with Tay-Sachs are unable to process a fatty substances,
which builds up in the body and leads to blindness, deafness,
paralysis and death by age 4. Since screening for Tay-Sachs carriers
began in the early 1970s, the number of cases has dropped by 90%.
Other diseases that Ashkenazi Jews are frequently screened for
include Canavan disease and Niemann-Pick disease, which lead to
death in early childhood, and debilitating conditions like cystic
fibrosis.
Dr. Ephrat Levy-Lahad, director of the Medical Genetics Unit at
Shaare Zedek Medical Center in Jerusalem, and colleagues wondered
how screening for a relatively mild condition like Gaucher affected
couples' family planning decisions.
Gaucher disease is the most common genetic disease among Ashkenazi
Jews. Scientists estimate that 6% to 10% of Ashkenazi Jews are
carriers of at least one mutation that can lead to the disorder.
Roughly 60% of eligible couples in Israel take the screening test,
Levy-Lahad said.
But among the eight to 14 Jewish genetic diseases commonly screened
for, it is also the most controversial, Grinzaid said. Even knowing
which mutations are in a fetus' genes, she said, "we're still not
able to predict what's going to be wrong with the child. It can be
anywhere from something that presents in childhood, which is
treatable, to something that can never present. . . What do you do
with that?"
Among children who inherit two faulty genes, the most common result
is Type 1 Gaucher. Half will become symptomatic at some point in
their lives, when harmful amounts of glucocerebroside build up in
the spleen, liver, lungs and bone marrow.
Patients can experience pain and suffer from fatigue, although the
symptoms can be treated with biweekly infusions of the enzyme that
their bodies fail to produce in sufficient quantities. The
intravenous infusions take an hour or two at home and cost $100,000
to $400,000 a year.
The researchers surveyed all 10 centers in Israel that screen for
Gaucher disease mutations. Between 1995 and 2003, the centers tested
about 28,900 people and identified 83 couples where both partners
had a mutation.
The researchers were able to interview 65 of the at-risk couples,
who had a total of 90 pregnancies. In 68 of those pregnancies,
parents opted for an amniocentesis or chorionic villus sampling to
test for Gaucher in their fetuses.
Sixteen of those tests were positive for the disease. In four of the
cases, couples opted to terminate their pregnancies.
The researchers surmise that lack of information about Gaucher may
have played a role in some of those decisions. Among 13 couples who
discussed Gaucher with an expert, one had an abortion. Three couples
did not discuss the disease with an expert, and all of them had
abortions, according to the study.
One couple, which learned that their particular mutations could lead
to one of the most severe -- and untreatable -- forms of the
disease, did not get pregnant. Those types can cause death in early
childhood or severe neurological degeneration, and they are no more
likely among Ashkenazi Jews than members of other ethnic groups.
In an editorial accompanying the study, Dr. Ernest Beutler said the
Gaucher test does little to benefit carriers or their offspring.
Instead, he said, it serves mainly to enrich hospitals, testing
laboratories and pharmaceutical companies.
"Children are likely to be treated when they don't really need
treatment," said Beutler, who chairs the department of molecular and
experimental medicine at the Scripps Research Institute in La Jolla.
"You get a child that's 8 or 10 years old and has a slightly
enlarged spleen and their hemoglobin is a little low. You can watch
a child like that. But once the diagnosis is made, there's pressure
to treat. People tend to say, 'Nothing's too good for our child.' "
Parents' choiceJust knowing that Gaucher is present can shape the
lives of healthy children. "Maybe they won't be allowed to play
soccer with their friends," Beutler said. "Maybe they'll wind up
being checked by a doctor every two months. It can really change
their life and their self-image."
Dr. Robin A. Ely, who raised three children with moderate levels of
the disease, said she had counseled couples in the U.S. who were
advised by their doctors to abort when genetic tests confirmed a
Gaucher diagnosis.
"I tell them, 'This is your choice, but I think it's a mistake,' "
said Ely, medical director of the National Gaucher Foundation based
in Tucker, Ga. "It's almost Nazi-like. It's eugenics."
But what may seem like a mistake to one family may be the right
choice for another.
For instance, the high cost of enzyme replacement therapy may tilt
some couples toward abortion, Levy-Lahad said. Insurance plans in
the United States typically cover the treatment, but patients whose
policies include a lifetime cap may run into trouble.
Cost was probably not a factor for couples in the study because the
treatment is covered by Israel's national health insurance.
One of the couples interviewed by researchers said they were
concerned about how they would pay for treatment if they left the
country. However, they elected to carry their Gaucher baby to term.

karen.kaplan at latimes.com