What is Becker?
Becker and Duchenne are medical conditions that are the result of gene variations on the same dystrophin gene on the X chromosome.
Becker type muscle wasting symptoms tend to develop more gradually but in some cases can be as severe as some Duchenne. It is thought that some Becker type gene variations are totally benign with people growing up and living into old age unaware of any problems. These are going largely undetected in the general population.
So why are there such differences in the symptoms of a disease that has the same cause?
Much depends on where in the gene the deletion, duplication or single point variation occurs. This will determine if the gene can be read through to produce RNA and then some form of the dystrophin protein.
Generally in Duchenne the gene has a break or stop codon that prevents any protein being made in the muscle cells. The consequences are severe muscle wasting leading to paralysis in late teens.
In Becker the gene break is in frame so that some protein albeit shortened is produced and this appears to give muscle cells some protection against the severe progression of the disease. So Becker patients generally experience slower muscle wasting.
The dystrophin gene is not a linear structure. It folds with hinges. The position of the break could also affect this folding structure that might make some shorter proteins stronger and more stable than others. Hence some Beckers even with large deletions might well be very stable.
Today we have no clear mapping of gene variations on the dystrophin gene with clinical symptoms. But in any case it is important to get your gene variation results from the geneticist logged onto the DMD Registry – www.dmdregistry.org as this will help to identify future treatments for your gene type.