A New York City Marathon runner will be defying the odds this Sunday despite being diagnosed with a disease that makes it hard for him to be active.

Nathan Oertel was diagnosed with the inflammatory disease ankylosing spondylitis, which affects his spine and joints, at just 20 years old.

It wasn't until 10 years later when Oertel went to a clinical trial at NYU Langone Brooklyn that he received treatment that helped him be active again.

Oertel will be running 26.2 miles during the marathon.