WEDNESDAY, June 15 (HealthDay News) -- Twins with a rare
disorder that left one of them unable to walk are now playing
soccer and running track, thanks in part to cutting-edge technology
known as whole-genome sequencing that enabled physicians to better
treat the disorder.
Soon after Alexis and Noah Beery were born it was obvious to
their parents, Joe and Retta, that the twins were different from
their older brother, Zach. They cried nonstop, vomited frequently,
had poor muscle tone and missed their developmental milestones.
Looking for answers, Retta took them to dozens of specialists
who did blood draws and brain scans. Eventually, physicians
diagnosed the twins with cerebral palsy, which can be caused by a
lack of oxygen in the womb that injures the brain, leading to
movement difficulties, muscle weakness and tight, constricted
muscles or joints.
Despite various therapies, at age 5, Alexis's condition suddenly
worsened, something Retta knew wasn't typical of cerebral palsy
from the countless hours she'd spent researching her children's
condition. Alexis was having difficulty swallowing, could hardly
sit up on her own and was wasting away.
Desperate, Retta again went looking for answers.
During her hunt, she came across an old newspaper article about
a rare disorder, dopa-responsive dystonia, which is caused by a
deficiency of the brain neurotransmitter dopamine and is often
misdiagnosed as cerebral palsy. The symptoms matched her
daughter's: tremors, muscle rigidity and difficulty walking,
especially later in the day.
"Everything in me knew this is what Alexis had," Retta said.
And there was good news: Dopa-responsive dystonia is
The Beerys, who were living in Phoenix, Arizona at the time,
found a physician in Michigan who was looking for people with
dopa-responsive dystonia who had been misdiagnosed. He prescribed
levodopa (L-Dopa), the same medication used to treat people with
Parkinson's, another disease in which dopamine deficiency also
plays a crucial role.
That night, Alexis slept through the night for the first time in
her life. Within 24 hours, Alexis, whose disease had grown more
severe more quickly than her brother's, was able to walk on her own
for the first time in months.
"We knew we were witnessing a miracle," Retta said.
Soon after, Noah's condition also began to worsen and he too saw
marked improvement on L-Dopa.
All was going well until about six years ago when Alexis
developed a severe, nagging cough and breathing difficulties.
Doctors again were stumped. Asthma medications didn't work. After
Alexis passed out from lack of oxygen, she had to give up sports.
The family was giving her epinephrine in a nebulizer multiple times
daily to keep her breathing.
By this point, the family had moved to San Diego and Joe Beery
was working for Life Technologies Corp., based in Carlsbad, Calif.,
which makes gene sequencing technology used by researchers at
Baylor Human Genome Sequencing Center. The Beery's wondered if
whole-gene sequencing, which scans the entire genome for mutations,
would yield answers about what was wrong with Alexis.
When the researchers at Baylor sequenced the twins' genome, they
found that the twins had a particular subtype of dopa-responsive
dystonia that prior research has shown isn't due to just a dopamine
deficiency, but also to a serotonin deficiency, another key
Only about 3 percent of people with dopa-responsive dystonia
have the mutation, said lead study author Matthew Bainbridge, a
post-doctoral fellow at Baylor, whose research was published in the
June 15 issue of
Science Translational Medicine.
When the family got the results in January, physicians put the
twins on a supplement, 5-HTP, to boost their serotonin levels, and
within weeks Alexis's cough subsided. Noah also saw an improvement
in his fine-motor skills and focus at school, something he'd been
Experts say the findings are among the first time that
whole-genome sequencing has revealed information that physicians
could immediately use to improve treatment -- something that may
herald a new era of medicine.
"Up until this point, a lot of gene sequencing is basic science. We can determine which gene is involved, but the next step, developing the drug, isn't there yet," Bainbridge said. "This is what makes this study fairly unique in that it was medically actionable."
Other experts agree there is more to come. It was only in 2003
that the first whole-genome sequencing was completed -- the Human
Genome Project, which was enormously expensive, according to
Stephen Kingsmore, director of the Center for Pediatric Genomic
Medicine at Children's Mercy Hospital in Kansas City.
Subsequent sequencings cost between $1 million and $2 million.
Today, the cost is about $10,000, said Kingsmore, who wrote an
Even newer, more targeted and less expensive technologies have
the potential to bring down the cost to $5,000 or even lower,
Kingsmore said, although as of now, those are not available outside
of research institutions.
But if such lower-cost sequencing became available, it could
lead to more accurate, faster diagnosis of the nearly 3,000
Mendelian diseases, or diseases caused by a mutation on a single
gene, such as sickle cell anemia or cystic fibrosis, for which
research has identified a known genetic cause.
Today, families often spend many stressful months and years
visiting doctors and undergoing tests to figure out what's going on
with their child.
Kingsmore said that for some of these diseases, whole-gene
sequencing might help solve the "bottleneck" in terms of the
inability to make a diagnosis -- or a diagnosis that takes so long
that the child is very late in the disease before physicians figure
out what is wrong. "If we can make an early diagnosis, that will
breathe fresh life into looking for new treatments," Kingsmore
Today, Retta Beery is like many other moms. She spends
afternoons shuttling her now 13-year-old twins to soccer,
volleyball and track practice. But she may have a different take on
"Every time they do anything, we continue to be in awe," she said. We don't take it for granted. We know how incredible it is they are able to function and to do the things that they are doing. We want them to know this is their testimony, and what has really shaped our whole family in so many ways."
Move has more on dopa-responsive dystonia.
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
Copyright © EBSCO Publishing. All rights reserved.