What is exon skipping?
If you imagine that the gene is made up of segments (or exons) which ultimately spliced together to make a recipe or message for producing the protein:
A deletion of exon 71 would be considered “in frame” because the 70 and 72 could still joint up and allow transcription. However, a deletion of exons 48 through 50 would be “out of frame” since 47 and 51 do not splice back together to form the message:
The message would become corrupted and the gene product, in this case dystrophin, would be dysfunctional or even totally absent:
The drug Eteplirsen will link 47 and 51 back together again, and in so doing restore the reading frame and facilitate transcription of an altered but hopefully functional gene product:
Does it work?
A clinical study started in August 2011
The preliminary results from this study were very encouraging – the boys who received the drug maintained strength and walking ability and there were no treatment related adverse effects.
What’s the next step?
The device, which is similar to an electric toothbrush, consists of a detachable spoon, a motion-generating platform, a controller/sensor, and a rechargeable battery. It detects the frequency of the patient’s tremor, and then counteracts that motion, to keep the spoon stable.
Patients in the study still had tremor, but they were less likely to spill their food when eating with the spoon.
The device is now commercially available, and costs around $295.