Ricki Lewis

The end-of-year FDA approval of the first CRISPR-based therapy, for sickle cell disease, came a mere dozen years after Jennifer Doudna and Emmanuelle Charpentier introduced the technology. They shared the Nobel Prize in Chemistry in 2020.

 

CRISPR is one of the better abbreviations in genetics. It's certainly more memorable than RFLPs, GWAS, and even SNPs, so euphonious that few reports – technical or otherwise – actually use the term "clustered regularly interspaced short palindromic repeats." CRISPRs are short DNA sequences, peppered with repeats, that latch onto DNA-cutting enzymes, commandeering and directing them to snip certain parts of a chromosome.

 

The genomes of certain bacteria naturally harbor CRISPR sequences. The microbes deploy them to dismantle the genetic material of infecting viruses, a little like an immune response.

 

To continue reading, go to DNA Science, where this post first appeared.

I can't believe it's been a decade since I researched and wrote The Forever Fix: Gene Therapy and the Boy Who Saved It. Since then I've shared stories of other families doing amazing things to help researchers develop treatments for their loved ones' rare diseases. The need is all the more compelling in these days of the pandemic.

 

Now entering its fourth decade, gene therapy continues along what seems at times a never-ending rocky road, riding the waves of fantastic success and plunging setbacks.

 

A Slow Start

 

The US has approved just two gene therapies. Luxturna has provided vision to patients with a form of retinal blindness (the basis of The Forever Fix), while Zolgemsa treats spinal muscular atrophy, a disease typically lethal in young children.

 

The latest in a series of setbacks, beginning in 1999 with the death of 18-year-old Jesse Gelsinger, came just yesterday. The FDA placed a clinical hold on two gene therapy trials for sickle cell disease, following reports of blood cancer in two trial participants. But that's not all.

 

To continue reading, go to DNA Science, where this post first appeared.

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 Stem Cells.

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. Read More 

Today is both DNA Day and World Malaria Day. As I was pondering how to connect the topics, e-mail arrived from my “son,” a medical student in Liberia. He had malaria, again, and this time it had gone to his brain.

I “met” Emmanuel in 2007, when he e-mailed me after finding my contact info at the end of my human genetics textbook, which he was using in his senior year of high school. He is my personal link between DNA Day and World Malaria Day. But the dual commemoration also reminds me of the classic study that revealed, for the first time, how hidden genes can protect us – that carriers of sickle cell disease do not get severe malaria. Read More