WASHINGTON (WUSA) -- You just saw him play Sherlock Holmes on the hit CBS primetime drama Elementary but in real life Jonny Lee Miller is trying to crack a cold case on a deadly childhood disease and there is nothing elementary about that.

His super sleuth skills help him solve crimes. However, it is the mystery behind a rare deadly childhood disease that had Jonny Lee Miller on Capitol Hill Thursday pushing Congress to help fund research for treatment and a cure.

"It's my first time in DC actually, it's a huge honor. It's very humbling as well to sit in a room and listen to people with much more to contribute than I have," Miller said.

Miller made this his mission after a crew members' son about the same age as his own little boy was diagnosed. "Sometimes you've just got to help the person standing next to you, right?," he says.

Five-year-old Jonah Weishaar has San Filippo syndrome. He is missing a key enzyme that essentially can lead to major problems with the Central Nervous System.

Jonah's mother Jill says, "It causes really irregular behavior and brain damage. So, they start losing their speech. Some of these kids don't sleep for nights on end. Then they start getting very aggressive,anxious and agitated." Jonah's mom Jill calls it pediatric Alzheimer's. Most children are not even diagnosed until their preschool years and do not live past their teens. She still remembers the day they found out.

Jill talks about how she gets through the day. "When you're a mom, so you get your child dressed, and fed and ready for school. Your child is what keeps you going and is what gets you out of bed in the morning. So you can't fail your child. You can't right? So, that's how I get through the day. I can't fail, I can't fail Jonah," she says.

That's how Jonah's Just Begun Foundation began. Instead of his usual spot behind the camera, Jonah's dad got out in front and the crew of Elementary followed.

"Right now we have almost spearheaded this with almost no federal dollars. I've been nickel and diming my friends and family to pay for the research," Jill says.

Jill and Jeremy hope clinical trials will lead to a cure. Miller will not stop until there is one.

"I wasn't out, I wasn't out looking for a cause. But there was one right next to me right there. And I think that," Miller says. "And I think that that should happen more in the world if you pay attention to your surroundings, you know. And realize well what's the..I can't personally solve this problem. But I can do a little piece, a little bit."

To learn more about San Filippo Syndrome, you can check out 'Jonah's Just Begun' website.