LYNNFIELD – Jeff and Lori Gaudet of Lynn, along with their daughters Jennifer and Josilyn and many of their family friends, plan to step off with hundreds of others from Lynnfield Common on Sunday morning for a 5-mile walk in pursuit of a cure for Cystic fibrosis.Now in its 15th year, Lynnfield’s Cystic Fibrosis Great Strides Walk begins at 11 a.m., with registration at 10 a.m.”It doesn’t cost anything to participate, but any donation is welcome,” said Jeff Gaudet, noting that 90 percent of every dollar donated goes directly to fund research toward a cure for the chronic genetic disease.For the Gaudets, the walk is personal, as 16-year-old Josilyn, who is finishing her freshman year at Lynn Classical High School, has battled the debilitating condition most of her life.”She was diagnosed when she was 3,” Gaudet said, noting she was hospitalized for weeks at a time through most of her childhood years.Cystic fibrosis (CF) is a genetic disorder that affects the lungs, pancreas and liver, and results in thick secretions. The name of the condition is derived from characteristic scarring (fibrosis) and cyst formation within the pancreas.Gaudet said when both parents carry the gene that causes CF there is a 1-in-4 chance that each child will develop CF. Their eldest daughter Jennifer, 17, a senior at Lynn Classical, does not have the condition.”Right now the average life expectancy (for those with CF) is 34,” Jeff Gaudet said. But he added recent breakthroughs are encouraging and a new medication, Kalydeco, approved by the FDA in 2012 and which his daughter takes today, has shown promise. “There’s been a lot of headway made the past four years. I’m 100 percent confident there will be a cure for this.” Until there is a cure, Gaudet said, research is extending the lives of those with CF, which is why he said the Great Strides Walk is such an important cause.”Josilyn is doing great today,” he said. “She has the same doctor today at Boston Children’s Hospital who treated her when she was 3 at Mass General. And there are doctors today specializing in treating adults with CF. Not long ago there wasn’t a need for that.”Gaudet said the Lynnfield Great Strides Walk was founded 15 years ago by Jeff Tomei and Sandy Peruffo, whose son, Ben, died earlier this year from CF. The Lynnfield Walk is one of hundreds of Great Strides Walks around the nation, all to benefit the Cystic Fibrosis Foundation.Gaudet said the Lynnfield walk typically has from 400 to 500 participants. This year, he said, there are 16 teams, including his family’s “Team Cheeka,” for Josilyn’s nickname. Show up at Lynnfield Common Sunday morning if you’d like to join the cause, or to donate to Team Cheeka directly online, visit www.cff.org and click the link for Great Strides Walk, Lynnfield.Parking and restrooms will be available at Lynnfield Town Hall, and there will be hot dogs and cold drinks served to participants after the walk, as well as entertainment provided by a disc jockey.Sean Leonard can be reached at [email protected].