Pontfract auntie Lyndsey Clayton hopes to run up cash for the hospital where her nephew had a liver transplant.
She will take part in the London Marathon on April 21 to raise money for St James’ Hospital in Leeds where her nephew James Hodgson was treated four years ago.
James, now six, was diagnosed with genetic disorder Alpha-1 antitrypsin deficiency –where the body does not make enough of a protein that protects the lungs and liver from damage – and had to have a liver transplant when he was two.
Miss Clayton, 36, of Millbeck View, said: “James is doing amazingly well and studying hard at school.
“We all remain positive that he will have a long, healthy and happy future, like any other boy his age.
“He is an inspiration to everyone. He has been so brave when faced with all the medication, regular check ups involving scans and countless blood taking.”
Miss Clayton has tackled the Great North Run and several 10k events, but said next month’s marathon will be her toughest challenge so far.
She added: “Running the London Marathon will be the hardest thing I will ever do, but it is all for James and all the other children that suffer from the disease.
“We cannot thank the healthcare professionals enough for their care and support.”
To sponsor Miss Clayton visit www.virginmoneygiving.com/Lyndsey4James