The hottest topic in biology this past year has been new methods of slicing and dicing DNA. The new tools, called CRISPER/CAS,https://en.wikipedia.org/wiki/CRISPR are simply enzymes (proteins) borrowed and then modified from bacteria- the bacteria use them as a rudimentary immune system. While DNA clipping tools have been around since the 1970s, the new tools are guided by a strand of RNA to be directed specifically- and programmably- to the site of interest. Since DNA contains billions of sites, this is rather important. If you want to debug a computer program, you had better get to the right line of code. Same thing.
In spite of recent success with a muscle disease in mice, actually doing this in a human is a ways off. First of all, there is the question of slicing and dicing the DNA ONLY in the right place. Secondly, it is a lot easier to cut something out (like in the mouse model) than it is to insert a a corrective sequence. And thirdly, getting the tools to the DNA requires use of a virus as a vector, and these tools can be quite bulky. Improvements will need to be made in all of these areas before a human trial is possible, and the disease will have to be chosen carefully- I assume, pick something relatively easy first. One step at a time.
None of these caveats detract from the excitement that we can now guide an enzyme to the correct site of its work. Look for Nobels in this area real soon, Dr. Doudna and Charpentier, now both competitors in different biotech companies, and then Dr. Zhang’s group from MIT, all squabbling over the intellectual property rights.
As regards arthritis and cartilage loss, one possible approach with such technology would be to disable the enzymes which degrade cartilage…