Emily Monk, 35, from Telford, who worked as a geo-technical engineer and was a talented gymnast in her youth, suffered from Ehlers-Danlos syndromes, a group of rare inherited disorders that affect connective tissue.
She was diagnosed aged 29, and after struggling with the condition for six years, died last November.
Now her mum Wendy Hillman and her friends Debbie Havard, Natalie Carr, Rachael Dodd and Jane Dodd are walking 26.2 miles around Telford this Saturday to raise money for Ehlers-Danlos UK. They've already raised more than £3,000.
Explaining more about the illness, Wendy said: "There is a broad spectrum of severity. On one end you have celebrities including pop star Sia, actress Jameela Jamil and comedian Russell Kane who, in their public lives, appear to be able to still function strongly.
"But on the other end you had Emily. She struggled every single day with simple tasks that we all take for granted. Unfortunately there is no cure and Emily eventually lost her battle at the young age of 35.
"Please feel free to come out and join us for part of their route on the day. They will be doing part of the Telford T50 route, starting at the Wellington train station at 6am, doing stages 4, 5, 6 and part of 7 of the route, finishing up at The Lion Pub in Priorslee to celebrate.
"Please sponsor anything you can to help support such a worthy cause."
While she was poorly, Emily was instrumental in setting up support groups to help other sufferers talk to one another and boost morale.
To support the fundraising of Wendy and the team, you can donate at justgiving.com/fundraising/our-marathon-needs-you