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Ricki Lewis

Genetic Linkage

Gene Therapy for Canavan Disease: Max’s Story

December 19, 2012
Tags: gene therapy, Canavan disease
Max celebrated his 15th birthday on October 13, 2012. His best friend is his brother Alex, a future neuroscientist.
I’m thrilled about the encouraging gene therapy results just published in Science Translational Medicine from Paola Leone, PhD and R. Jude Samulski, PhD, and colleagues. “Long-term follow-up after gene therapy for Canavan Disease” updates a project that has its origins in the mid 1990s. Canavan disease is a brain disorder present from birth.

I’ve been following some of the kids who’ve had the gene therapy. One patient in particular – Max Randell – has been in my human genetics textbook since age three, his progress updated with each edition.  Read More 
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Excerpt about Canavan disease from "The Forever Fix: Gene Therapy and the Boy Who Saved It"

December 19, 2012
Tags: gene therapy, Canavan disease
Max Randell smiles at his middle school graduation.
The excerpt below supplements the blog entry that is beneath it and also at Public Library of Science. It is from The Forever Fix: Gene Therapy and the Boy Who Saved It, (St. Martin's Press, 2012).


I sat at a table with Paola, Mike, Max and Max’s charming little brother Alex, who was eight going on twenty-eight. While the adults ate chicken alfredo (except for vegetarian Paola) and the kids downed chicken fingers and fries, Mike leaned over Max, pulled up his shirt, and deftly attached a bag of cream-colored stuff to the feeding tube coming from his son’s stomach, holding it aloft for the food to go in. At the front of the ballroom, Ilyce, svelte in a shimmering blue gown, was getting ready for her annual thank-you. Read More 
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When An Arm Is Really A Leg

December 14, 2012
Tags: homeotic
The hands of a person with Liebenberg syndrome may actually be feet. (Credit: Dr. Malte Spielmann)
Flipping the X-ray showed Stefan Mundlos, MD, that his hunch was right – the patient’s arms were so odd and stiff because the elbows were actually knees.

The recent report from Dr. Mundlos’ group at the Max Planck Institute for Molecular Genetics, complete with a genetic explanation for the condition, flew under the radar of the press-release-driven science news aggregators. But I noticed it because I worked on this sort of thing in grad school – flies with legs growing out of their heads. Read More 
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The Battle of the Prenatal Tests

December 9, 2012
Tags: chromosomal microarray, DNA chip, genome sequencing, translocation, prenatal testing, amniocentesis, ultrasound, genetic counseling
(credit: NHGRI)
The young couple looked at me expectantly as I re-read the amnio report and tried to decide what to tell them.

“The ultrasound from 15 weeks looks fine,” I stalled, trying to present the good news first.

“What about the amnio?”

“Well, there is something unusual. It’s the Y chromosome. Part of it appears to be flipped. What we call an inversion. It’s a little like if the exits on a highway turned around,” I explained.

The couple looked at each other, puzzled, then back at me, and he reached for her hand.

“What does that mean?” they both asked. Read More 
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Cialis Comes Full Circle – Help for Muscular Dystrophy

November 29, 2012
Tags: Cialis, muscular dystrophy, erectile dysfunction, Viagra, Science Translational Medicine, repurposed drugs
One symptom of Becker muscular dystrophy is fatigue and injury of exercising muscles, such as in gripping a weight.
Becker muscular dystrophy is a muscle-wasting disease that is rarer and less severe than the more familiar Duchenne type. Both conditions are basically untreatable. But according to a study published today in Science Translational Medicine, Cialis may alleviate the associated muscle fatigue and damage.

Yes, Cialis. The erectile dysfunction drug.

To anyone who’s followed the Viagra story, use of its cousin Cialis to treat muscle disease is not so much repurposing as it is a logical extension, based on regulating blood flow.

Viagra, developed in 1989, began its ascent three years later, when participants in a clinical trial to treat angina, which is chest pain due to blocked blood flow, reported strikingly improved erections. Taking a pill to treat what was about to evolve from “impotence” to “erectile dysfunction” trumped penile implants and injections, or older approaches of ingesting camel hump fat, jackal bile, or various herbs. Pfizer introduced Viagra to the world in 1998. Read More 
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JIM: More Compelling Than GATTACA

November 24, 2012
Tags: GATTACA, dystopia, genetic engineering, Eugenics, science fiction
"Jim" the film is the brilliant brainchild of self-taught filmmaker Jeremy Morris-Burke.
For 15 years, the film GATTACA has been synonymous with “genetic dystopian future,” and has become a mainstay of genetics classrooms. But I’ve found a better film. It’s called, simply, JIM.

I never could connect with GATTACA, the dark tale of an assumed genetic identity in a society where the quality of one’s genome dictates all. Perhaps because in 1997, the pre-genome era, the idea of ordering a DNA test over the Internet was still science fiction. But ironically GATTACA’s “not-too-distant” future, in which a genetically inferior “invalid” impersonates a “valid” to achieve a dream, sets up a too-obvious conflict, with the details and resolution contrived. I know this from years of reading fiction and watching soap operas. Read More 
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Mice With Human Liverlets Test New Drugs

November 17, 2012
Tags: drug-drug interactions, drug development, hepatitis C, mouse models
“Scientists at Stanford have produced mice with human brains, pigs with human blood flowing through their veins, and a human born to mice parents and mice with human heads.”

So wrote a student summarizing the “Genetically Modified Organisms” chapter of my human genetics textbook a few years ago. Two of the four comments are true, sort of.
 Read More 
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Why I Don't Want to Know My Genome Sequence

November 2, 2012
Tags: exome, genome, Human Genome Project, Craig Venter, James Watson, Ozzy Osbourne, Francis Collins
Even after writing 10 editions of a human genetics textbook, I don't want to know my genome sequence. Yet.
Famous folk have been writing about their genome sequences for a few years now. But when I received two such reports at once last week – about genetics researcher Ron Crystal, MD, and a hypothetical (I think) story about President Obama, I knew it was time to take action.

Or, in my case, inaction. Read More 
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Male DNA in Female Brains Revisited

October 25, 2012
Tags: microchimerism, prenatal diagnosis, genetic testing, systemic sclerosis, cell-free fetal DNA, non-invasive prenatal testing
Fetal cells remain in moms -- that isn't news. But the discovery of fetal DNA in women's brains is. (credit: Jay Shendure lab)
“Some women actually have men on the brain” beckoned the headline from the LA Times on September 27, echoing an article in PLoS One describing the discovery of male fetal DNA in the brains of pregnant women. It was “an astonishing finding,” according to the newspaper, necessitating “a new paradigm of the biological self” according to lead author J. Lee Nelson of the Fred Hutchinson Cancer Research Center and the University of Washington.

I suspect Dr. Nelson was quoted out of context, for the idea of two genetically distinct populations of cells, or their DNA, residing in one individual isn’t new. It’s called microchimerism. Read More 
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Prenatal Genetic Testing: When is it "Toxic Knowledge"?

October 18, 2012
Tags: prenatal genetic testing, chromosomal microarray, copy number variant, Autism, developmental delay
When I was a fetus, I was left alone. My amniotic fluid and chorionic villi were untouched, and I arrived apparently normal, except for a mark on the part of my anatomy where a bullet “directly bit” Forrest Gump.

Perhaps that’s too much information.  Read More 
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