Hollie Murray, who lives in Fagg's Road, will join a stampede of runners on the 26-mile track in aid of the Down's Syndrome Association, a condition her uncle, 51-year-old Lawrence Murray, was born with.
Her participation in the charity run will also complete her 30th birthday wish to do something for a worthy cause and she hopes her uncle will be able to cheer her on from the sidelines in April.
Ms Murray, who is the director at Lifestyle Training Ltd in Wembley, said: "This is the year of my 30th birthday and I want to do something to help a charity that is close to Lawrence and my family's heart.
"My grandmother who is 92-years-old is so happy that I'm doing this marathon for the Down's Syndrome Association as it will help other people like her son."
To help drum up more funds she will be running bootcamps at the Wembley site on some Sunday's.
She hopes to raise £1,800 for the charity which will help towards supporting survivors like her uncle Lawrence.
She describes her uncle who is in a wheelchair and suffers from many other medical problems as a "brave and strong man".
Ms Murray added: "He is 51 and has been through so much, 16 years ago he was on a life support machine from a random epileptic fit.
"Prior to this he went to college, swam, played football and loved it all, now he can't do any except watch his favourite team Manchester United on TV.
"He is now fully disabled in a wheelchair, when he was taken off life support he had to re-learn everything, from walking to feeding himself.
"With his disability it made it harder, he was also left with a permanent tracheostomy tube (to help with breathing), on a ventilator at night and has many other illnesses.
"Lawrence has gone through so much but still fighting strong."