MERCER ISLAND, Wash. – For years it was a mystery. Ann Tootill did not know what was wrong with her daughter Shannon. Doctors eventually diagnosed her with Sanfilippo Syndrome.

“It is sometimes referred to as Pediatric Alzheimer’s. There is no treatment for it, and there is no cure,” said Tootill.

As Shannon grew, the disease gradually took over.

“She lost her memories. She didn't know her family anymore. She couldn't express herself. She lost her ability to walk,” said Tootill. “We were very hopeful that we would get a miracle, but the miracle didn't happen. She went into a steep decline when she was about 18, and died in December 2015 when she was 21.”

Tootill frequents a Facebook page that connects families dealing with the rare and fatal genetic disorder. That’s how she found out about the Rally on Rainier, an effort led by Carl Kapes.

“I have two children with Sanfilippo Syndrome,” said Kapes. “My kids were diagnosed 7 years ago, and there was no FDA treatment in the pipeline or anything. So we climbed Mount Kilimanjaro in 2012, and raised a bunch of money and moved some things forward.”

He says there's now an FDA approved clinical trial underway. The Rally on Rainier is to raise more funds for more research. It's a fight for his family and all the others battling something so big.

“We are doing this for them and we want them to be with us every step of the way,” said Kapes who plans to carry a flag bearing the names of kids with the disease to the summit.

“I don't know how he managed to do it. He is a hero,” said Tootill.

You can track the progress of Rally on Rainier here.

Photographer Dan Salvo is documenting the team’s journey here.