Showing posts with label muscular dystrophy. Show all posts
Showing posts with label muscular dystrophy. Show all posts

Thursday, November 15, 2007

Myostatin Man

One of my receptionists at work is dog-crazy and breeds whippets. Recently i came across an amazing photo of a so-called "Bully" Whippet- the Schwarzenegger of Whippets!
This dog is homozygous for a loss-of-function mutation in it's myostatin gene. Heterozygote whippets are faster runners than wild-type.
Belgian Blue cattle have been bred to have a similar genetic mutation. These "double muscled" cows produce 20% more meat but are so bulky they need to be delivered by caesarian!
The absence of myostatin in laboratory mice reduces the severity of obesity and diabetes , as well as helping muscle strength in the mouse model of Duchenne muscular dystrophy. (There is currently a trial testing a monoclonal antibody to myostatin in patients who have a form of muscular dystrophy known as fascio-scapulo-humeral dystrophy).
There have been several cases of myostatin mutations in humans including a case report in NEJM in 2004 of a baby boy born with enlarged muscles, and stimulus induced myoclonus (muscle twitching). The latter settled in 2 months, and other than being incredibly strong and 'muscly' is otherwise well with no cardiac dysfunction. Interestingly, his mother was a professional athlete, and his pedigree contains a number of relatives with exceptional strength. I suppose they could buy him a bully whippet for christmas.
I wonder if the presence of a myostatin mutation invalidates the mother's athletic achievements?