Nope it's not mutated. I've had this before.
"how much growth you should expect" isn't as important so much as, "has the plant changed in size/shape at all over the last few days?" If the answer to the latter is no then you've got a PH problem.
I would suggest testing the PH. Getting a PH testing kit and making sure I was maintaining the right PH in the medium solved all growth issues I was having with my plants.
If you're worried about it growing slow I would suggest feeding it light nutes, unless you have some really really good soil.
Oh yea I forgot to say that overwatering can also cause deformed leaves.
I have popped like 30+ TGA seeds and there's nothing like this in the genes. A lot of times what people think are mutations are simply caused by issues with their growing environment.
Scroll down to "PH problems"
http://www.icmag.com/ic/showthread.php?t=11688