The Forever Fix: Gene Therapy and the Boy Who Saved It (324.0KB)
flyer / handout
March 26, 2015
Discovery of a new gene behind autism cleverly combines genetic techniques new and classic.
Autism has been difficult to characterize genetically. It is probably a common endpoint for many genotypes, and is a multifactorial (“complex”) trait. That is, hundreds of genes contribute risk to different degrees, as do environmental factors. Research reports implicate either dozens of genes in genomewide sweeps, or focus on a few genes that encode proteins that act at synapses, such as the < href="https://www.autismspeaks.org/science/grants/neuroligins-and-neurexins-autism-candidate-genes-study-their-association-synaptic-con">neuroligins and neurexins. (more…)
March 15, 2015
Stem Cells.Researchers from Johns Hopkins University have teamed two powerful technologies to correct sickle cell disease in a lab dish. Linzhao Cheng and colleagues have deployed CRISPR/Cas-9 on iPS cells to replace the mutant beta globin gene, published in
ACRONYMS AND ABBREVIATIONS
CRISPR conjures up images of fried chicken, but it stands for “clustered regularly interspaced short palindromic repeats” – short repeated DNA sequences interspersed with areas called spacers, like stutters. The pattern of repeats and spaces attracts an enzyme, Cas9, which is like a molecular scissors that cuts wherever short RNA molecules called “guide RNAs” take it. Here’s a fuller description. (more…)
March 6, 2015
December 7, 2014
• More than 7 numbers or letters
• Obvious to me, but not to anyone else
The genetic code popped into my mind, and has remained an endless source of diverse passwords, valuable because they may seem nonsensical to non-biologists. (more…)
November 19, 2014
Balanced polymorphism, aka heterozygote advantage, is a terrific illustration of ongoing evolution. And it pits the human body against all sorts of invaders – prions, viruses, bacteria, protozoa, and fungi. (more…)
November 19, 2014
Eman and I began a very special friendship when he first contacted me when using my human genetics textbook in college. Right now he is in a hospital with a fever, after finally convincing the staff to admit him. It might be a flare-up of his malaria, we don't yet know.
This post picks up in early October, when Ebola suddenly jumped from a topic rarely reported in the U.S. ,to major news when it arrived here. (more…)
October 24, 2014
Eman contacted me in 2007, after using my human genetics textbook in college. My husband Larry and I had been putting him through medical school in Monrovia -- until Ebola happened. Now the funds go for gloves, long sleeve shirts, detergents, food and medicine, to keep Eman and his family, including his almost-one-year-old son, Larry, safe.
This week Eman asked me to share his emails, which began arriving before many people here had heard of Ebola virus disease, or cared much about it if they had. The disease seemed, and was, half a world away.
The world is a small place. (more…)
October 12, 2014
Altered viruses are the vehicles that transfer healthy human genes into the cells of people in whom the genes aren’t working, providing a slew of new “forever fixes.” Nearly 100 gene transfer protocols are now in late-stage clinical trials. (more…)
October 10, 2014
HOW RARE IS RARE?
According to the National Organization for Rare Disorders, “rare disease” in the U.S. means affecting fewer than 200,000 people. These conditions number about 6,800, collectively affecting nearly 30 million Americans or 1 in 10 people. Many are single-gene diseases. That means that the chance of more than one family member being affected is quite high (see Mendel's first law). Unlike those, most (>90%) cases of ALS and breast cancer aren’t inherited as single-gene traits, but are sporadic. Mutations happen during a person’s lifetime in somatic cells, perhaps due to an environmental trigger. A family with one member who has ALS wouldn't have as great a chance as it affecting another as a family with Huntington disease, for example.
With so many causes of rare diseases, comparing statistics is an apples-and-oranges exercise. But I collected a few anyway, for prevalence (the percentage of a population with a particular disease at a given time). (more…)
September 28, 2014
post dealth with three very serious applications of DNA testing. But not all DNA testing is to detect health-threatening conditions.Last week’s
“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…)