KATHERINE Drewett is calling on everyone who can to join a bone marrow donor, in the hope of finding a match for her partner, who has a potentially fatal condition.

Jason Knott was diagnosed last year with hypertrophic cardiomyopathy, a thickening around one of the arteries in his heart, and meylodysplasia, which means his bone marrow is producing almost no blood cells or platelets.

Jason now has to have a blood transfusion every two weeks at Southampton General Hospital but doctors say his best long term hope is to find a match for bone marrow donation.

Unfortunately, there is no one currently registered who is a good enough match for Jason, 26, but Katherine hopes that if more people sign up, they could find the person they are looking for.

"Jason can't do much now," she says.

"He tries to do little things round the house, but he gets out of breath and feels weak very quickly. The day after a transfusion he's at his best, but he can only do little things.

"It's all quite traumatic for him and waiting for a donor is stressful.

"He just wants to get the transfusion done and get on with recovering. The longer it takes to find someone, the more difficult it is, both emotionally and financially. We're not sure how long his work can hold his job open for him, and benefits take a long time to come through.

"When you're working, you live to that wage, so now we've only got my income, it's difficult."

Katherine signed up as a potential bone marrow donor a few weeks ago, with the Anthony Nolan Trust, and was surprised at how simple it was to do.

After filling in a form, potential donors are taken a swap kit, which they rub inside their mouths, and return. If they are ever found to be a match for someone in need, they are then contacted.

"I'm appealing for everyone to register," says Katherine.

"People sign up to be organ donors, but I don't think people really think about stem cell or bone marrow donation, but it could save someone's life."

* For more information and to register with the Anthony Nolan Trust, visit www.anthonynolan.org. If you are over 30, there are other registers you can join, including DKMS, www.dkms.org.uk. Katherine and Jason have set up a fundraising page to ask for help to pay for some things for Jason to look forward to. For more information, visit www.gofundme.com/rh3m35-light-at-the-end-of-the-tunnel