The rare condition affects his muscles which will continue to weaken over time.
"It's hard to tell with my condition because there's a lot of things that I can do that others can't," Mr Tessmann said.
"So doctors are a little bit baffled at the moment.
"I've been able to live independently on my own for two years now, that's a pretty big achievement for myself with the condition that I have."
The 26 year old relies on a customised van to get to doctor appointments, gigs and to keep active.
Mr Tessmann and his mother have been saving for a new car, launching a GoFundMe in a bid to lighten the financial load.