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Glenn Nichols, surrounded by his hospice team. The author is in yellow.

Genetic Linkage

The Man Who Ate 25 Eggs a Day

March 6, 2015

Tags: cholesterol, statin, triglyceride, South Beach diet, genetic testing

Cholesterol isn't the enemy -- triglycerides are.
Each morning at the retirement community, the healthy 88-year-old man received a delivery of 25 soft-boiled eggs, which he would consume during his day. This had been his way for many years. He’d had one experience of chest pain that might have been angina, but aside from that, he had a healthy cardiovascular system. He recognized that his only problem was psychological: “Eating these eggs ruins my life, but I can’t help it.”

I think of the Eggman, a brief case report from 1991 in the New England Journal of Medicine, whenever "news" of cholesterol’s unsuitability as a one-size-fits-all biomarker resurfaces, as it does every few years and did again a few weeks ago. (more…)

DNA and Dating: Buyer Beware

September 28, 2014

Tags: DNA, genetic testing, DNA and dating

Is DNA dating destiny?
Last week’s post dealth with three very serious applications of DNA testing. But not all DNA testing is to detect health-threatening conditions.

“Born to Run? Little Ones Get Test for Sports Gene,” ran the headline on the front page of the New York Times, above an arresting image of a preschooler having his mouth swabbed for DNA. It’s from 2008, but remains a classic: I still assign it.

The sports gene company is apparently still around and still testing for variants in just one gene: ACTN3. Two copies of the R577X variant indicate inborn skill at endurance events, and no copies suggest a child stick to sprints. The lucky heterozygotes might excel at both! Never mind that a child has some 20,000 or so other genes affecting physiology.

DISSECTING A DNA DATING WEBSITE
The most damage a sports gene test can do is to keep a child from doing something she loves because of a DNA-obsessed parent. A more questionable application of DNA testing is as part of “relationship science,” something I learned about a few weeks ago when a reporter from healthline.com asked me about it. (more…)

Genetic Testing For All: Is It Eugenics?

September 21, 2014

Tags: genetic testing, eugenics, NIPT, BRCA, carrier testing, DNA

(NHGRI)
In recent weeks, there’s been talk of three types of genetic testing transitioning from targeted populations to the general public: carrier screens for recessive diseases, tests for BRCA cancers, and non-invasive prenatal testing (NIPT) to spot extra chromosomes in fetuses from DNA in the maternal bloodstream.

Are these efforts the leading edge of a new eugenics movement? It might appear that way, but I think not.

When I began providing genetic counseling 30 years ago at CareNet, a large ob/gyn practice in Schenectady, NY, (more…)

New Guidelines on Testing Kids’ DNA – the Cliff’s Notes Version

February 22, 2013

Tags: genetic testing, American Academy of Pediatrics, American College of Medical Genetics and Genomics, direct-to-consumer genetic testing

Should kids have genetic tests? It depends. (NHGRI)
Exomes are big news. Sequencing of the protein-encoding part of the genome is increasingly solving medical mysteries in children. It began with Nicholas Volker and his recovery from a devastating gastrointestinal disease with a stem cell transplant once his exome sequence revealed his problem. And recent Medscape assignments reveal the trend: 7 of 12 kids’ exomes leading to diagnosis at
Duke University
from May 10, 2012; whole genomes of 5 infants from the neonatal intensive care unit at Children’s Mercy Hospital and Clinics in Kansas City, Missouri from October 3, in under 2 days each, focusing on 600 single-gene diseases; and 300 patients at the Whole Genome Laboratory at the Baylor College of Medicine, with 300 more waiting -- 85% of them kids, from November 9, 2012. (You have to sign in to Medscape; it’s free.)

But wait.

Before we all run out to get our exomes and/or genomes sequenced, (more…)

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. (more…)

DNA Science -- My New Blog at Public Library of Science (PLoS)

September 27, 2012

Tags: Public Library of Science, PLoS, gene therapy, genetic testing, stem cells

I have a new blog at Public Library of Science (PLoS), DNA Science. Each Thursday I'll explore stories from real people experiencing opportunities and challenges posed by biotechnology, including genetic testing, gene therapy, exome sequencing, stem cells, and more.

I like to find the stories that no one else tackles, connect topics in unusual ways, dip into bioethics, and wherever possible, bring in the historical perspective that shows that "overnight breakthroughs" are almost always anything but. And the PLoS tag is opening doors -- I spoke with Dr. Francis Collins yesterday!

The first blog is "Human Embryonic Stem Cells Finally Reach Clinical Trials: Maurie's Story."

Join me on this new adventure!

Anticipation

February 25, 2012

Tags: rare diseases, rare disease day, spinocerebellar ataxia type 2, SCA2, SCA1, fragile X syndrome, expanding triplet repeat, genetic testing, ALS, Lou Gehrig's disease, Parkinson's disease, Huntington's disease, myotonic dystrophy, amyotrophic lateral sclerosis, Carly Simon, Anticipation, X chromosome, ALS, mutation, Ricki Lewis, The Forever Fix: Gene Therapy and the Boy Who Saved It

Jordan and Hailey Kohl. Spinocerebellar ataxia type 2 affects several members of their family, including Jordan.
“Anticipation .. is keepin’ me waitin’,” sings Carly Simon in her song made famous in a ketchup commercial. But “anticipation” in the genetic sense is just the opposite of Carly’s croon – it means a disease that begins earlier with each generation.

Doctors once blamed patients for anticipation, as if people with sick older relatives could worry themselves into suffering similarly. Then, in 1991, discovery of a new type of mutation explained the curious worsening of fragile X syndrome: an expanding triplet repeat. (more…)

instruction
Project to engage students in helping families with rare genetic diseases
Book Club Reader's Guide
Many challenging questions to stimulate thought and discussion.
Instructor's Guide
38 discussion questions to get students thinking and talking about gene therapy, including the science, ethical issues, and the drug approval process.
Narrative science
The Forever Fix is the uplifting true story of 8-year-old Corey Haas, who was cured of hereditary blindness just 4 days after gene therapy.
College Textbooks
A spectacularly-illustrated, clearly written human anatomy and physiology textbook, used in pre-health profession programs throughout the U.S.
A highly engaging, clearly written, beautifully illustrated introduction to the science of human genetics for the non-scientist. Now in its 11th edition, 12th to be published in September 2018.
Nonfiction
An ideal starting point for anyone who wants to know more about genes, DNA, genomes, and the genetic ties that bind us all.

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