Eliza O’Neill, a four-year-old from South Carolina, as Sanfilippo syndome, which affects just 2,000 children annually worldwide. The disease will have heartbreaking impact on Eliza as she is expected to lose her ability to talk and walk.

The good news is a clinical study of new treatments could help Eliza and other Sanfilippo sufferers, but it would cost $2.5 million to conduct the study.

So the O'Neill family set out to raise the money themselves in the hopes that experimental treatments would save their daughter's life.

As improbable as it may seem, they've raised over $800,000 online thanks to more than 16,000 individual donations. That's enough to begin production of the medicine to be tested in the clinical trial.

The next challenge is to raise another million by October to ensure the study can happen.

"Never before has the power of social media, crowd funding, and primarily the kindness of people around the world had a more direct impact on stopping a deadly childhood disease…and this year in 2014!" Eliza's father Glenn wrote on their Gofundme page. "History in the making and you are the reason. You paid for the medicine to end a disease!"

All donations to help Eliza are tax-deductible through the nonprofit Cure Sanfilippo Syndrome.