A CARING wee sister is about to tackle her first marathon in a bid to raise vital funds for research into her brother's rare illness.

Andrew Macnab from West Linton was diagnosed with the auto-immune condition dermatomyositis last year.

Fewer than one in a million people are affected by the incurable condition which causes skin rashes, muscle weakness, and inflammatory myopathy.

But treatments can control the symptoms and research is ongoing to try to find a cure.

Andrew's sister, Helen Keith, hopes her first attempt at a marathon later this month will boost the research work carried out by Myositis UK.

The former Peebles High pupil, who now lives Stow, told us: "Prior to Andrew's illness, I had occasionally considered running a marathon.

"All three of my brothers have completed marathons in the last few years - Andrew at Cape Wrath in the far north of Scotland, Colin at Nice/Cannes and Copenhagen, and Ross in Stirling.

"Now it's my turn, and as hard as every step will be, it is nothing in comparison to what Andrew has had to deal with in recent months.

"Simple tasks that we take for granted - like eating, drinking, sleeping, walking - have become incredibly tough for Andrew.

"It seems so unfair that someone who has previously completed a marathon now struggles to walk 50 yards due to the muscle-wasting effects this illness has had."

Helen and Andrew's mother, Jean Macnab, will be joined by organisers Pam Stephenson and Ann Southwood for a fundraising 24-hour challenge next month at West Linton Golf Club to also raise money for Myositis UK.

And Helen's fundraising page - www.justgiving.com/fundraising/helen-runs-edinburgh-marathon - has already gathered over £2,000 in sponsorship with more than a fortnight still to go until she reaches the starting line in Edinburgh.

Helen has become a regular jogger at Parkrun in Midlothian and has also completed a five kilometre dog jog in the capital.

But she believes it will be the fundraising mission that will drive her on to complete 26.2 miles later this month.

Helen added: "I found running to be a great stress-reliever during the early days of Andrew's admission to hospital, diagnosis and following treatments, and still do.

"I often think of Andrew when I run - about his own marathon effort in really tough weather conditions near Durness, and about how he'd love to be out running instead of having to struggle with this rare condition.

"I entered the marathon in November and at the turn of the year decided it would be a great opportunity - and positive focus - to raise money for the charity assisting those with myositis.

"Funding raised goes towards research into the illness, as well as support for those suffering from it.

"I have been overwhelmed by the support I have received - much of it a testament to Andrew's popularity and the high regard he is held in by family, friends and local people.

"He is an inspiration to us all and has always been an incredibly supportive big brother.

"Our family would also like to use this opportunity to thank the staff at the Borders General Hospital, in particular the Rheumatology Department, who have been very supportive in dealing with such a rare illness."