Looking at 11-year-old Tessa Lawson, it would be nearly impossible to tell the Bothell sixth-grader, who enjoys Sour Patch Kids, martial arts and soccer, is battling a largely unpublicized and invisible illnesses: linear scleroderma. Or, that her 16-year-old sister Isabel Lawson is fighting idiopathic arthritis, another painful autoimmune disease.

“It’s difficult at times, but I’ve had it since sixth grade,” Isabel Lawson said, who before her diagnosis said she never thought about having a chronic disease.

“I never really though ‘What if that happened,’” she said.

Idiopathic arthritis is a disease which fills the joints with fluids and wears down connective cartilage. Linear scleroderma causes skin to harden in lines along the body, which can cause difficulty moving, particularly if it grows over joints. The Arthritis Foundation is a national advocacy and support organization, and considers both conditions similar enough to address both. A commonly cited figure estimates there are around 300,000 children suffering from juvenile arthritis in America.

Both conditions can cause pain and discomfort, but that hasn’t stopped either of the sisters from following their passions.

Tessa Lawson loves Taekwondo, particularly choreographed routines, where she’s earned her blue belt which is the sixth-highest rank. She recently held a board-breaking demonstration for other children.

Both girls love and play soccer. Isabel Lawson plays for the Northwest Christian Sports League.

“My friend in first-grade asked me if I wanted to be on her soccer team, and I said yes,” she said, even though she thought she wouldn’t like it, she’s stuck with the game.

Aside from sports, Tessa Lawson loves animals, and cracks a huge smile as she describes the family’s two cats, dog, bunny and two fish.

Her sister, like most teenagers, enjoys hanging out with her friends, but also painting, particularly with acrylic paints.

Treating these chronic diseases is a lengthy battle. Charity Lawson, the girls’ mother, carries three homemade necklaces, each full of large beads. These are Beads of Courage necklaces, and Tessa Lawson receives one bead for each treatment she receives.

“Each bead represents a milestone in their journey,” their mother said.

The necklaces are each around a foot long.

“With arthritis and scleroderma, it comes in waves,” Charity Lawson said. “You have a good day, and without any rhyme or reason the next day you have a bad one.”

Treatment often includes a whirlwind of injections, checkups and cocktails of drugs ranging from chemotherapy prescriptions to anti-inflammatory medications.

The ultimate goal of these treatments is to send the diseases into remission, defined as going one year without a flareup. This is where Isabel Lawson is, and her sister Tessa’s condition has stabilized.

Charity Lawson said one of the biggest sources of help in helping her and her daughters fight the disease has been the Arthritis Foundation.

“It’s been such a blessing for us,” she said.

Both Charity Lawson and her daughters said one of the hardest parts of dealing with an invisible disease was people’s misunderstandings.

“You’ll have people who you’ll talk with them about it, and they’ll say ‘At least it’s not cancer,” Charity Lawson said.

The family hopes events the Arthritis Foundation puts on will help raise awareness.

Tessa Lawson was recently named the Youth Honoree for the foundation’s annual Santa Breakfast, a charity event which raises money and awareness for children’s arthritis programs.

Both girls are co-captains of their Jingle Bell Run/Walk team, T-Bell & Crew, which is held every year in Kirkland to raise money for the Arthritis Foundation.

According to the Jingle Bell Run/Walk website, more than $205,000 have been raised towards their goal of $755,800.

Through all their struggle, Charity Lawson said the children’s grandmother is a source of inspiration to them, who she said had multiple sclerosis and brain tumors.

“She would just push through so much pain,” Charity Lawson said.

It seems Charity Lawson may be right in that, as her daughter Isabel had a piece of advice for other children living with similar conditions.

“Don’t become the disease,” she said. “Don’t let it define you.”