The smiley two-year-old's short life has been filled with anxious hospital appointments and check-ups to monitor a genetically inherited neurological disorder, called Neurofibromatosis Type 1 or NF1, which could mean she develops benign tumours all over her body.

Her mother Carey discovered she carried the gene mutation NF1 gene when she was pregnant with Jessica.

"It causes benign tumours at the end of your nerves," she said. "Anywhere you have a nerve inside and out you can get these tumours.

"Right now we are quite lucky. She has these light brown latte spots on her skin, a big head, and small body but no one can tell us how it is going to play out. There is a big chance of getting tumours behind the eyes, tumours in the brain, down the spine."

Ms Russell said raising Jessica meant a crash course in the condition that medical professionals and nurses often weren't very familiar with.

"It affects one in 2500 people," she said. "No one has really heard of it but it is actually more common than cystic fibrosis and muscular dystrophy combined."

Ms Russell has undergone several surgeries in her lifetime to remove enlarged tumors and is ever hopeful her little girl will be able to get through without going under the knife.

"You hope she won't be affected too badly but you don't know," she said. "I always say you only get given what you can handle. There is no cure. They can remove your tumours but they can't stop them from growing."

The Russells have been instrumental in ensuring Canberra is part of Australia's first Mega Hero March and are proud to see there are more participants registered in the ACT than any other location nationally.

The Sunday event will offer a 2km and 10km walk. Each participant will receive their own golden cape and a sausage sizzle lunch afterward.

Organisers have so far raised $10,000 toward their $90,000 goal and hope to gather more money for their cause through a raffle on the day.

ACT families are so often forced interstate to get clinical support for medical conditions and Ms Russell said it was fantastic to see the wealth of local support.

"With events like these Canberra always gets forgotten," she said. "But look at us. We get together, we get behind causes and support our people. That is what I love about Canberra."