A COUPLE whose son died of a rare genetic disorder are facing a race against time to save their other child after he was diagnosed with the same illness.

Alyson and Ian Herbert were shattered when their son Edward, seven, died from the immune deficiency condition XLP.

And now just three weeks later they are facing further heartache after they discovered their four-year-old, Alex, has the same disease.

The couple, from Westwick, near Barnard Castle in County Durham, now face an agonising wait for their son to have a bone marrow transplant which they hope will save his life.

Librarian Alyson, 35, said: "This is one heartache too many. I've lost one son - I can't bare the thought of losing another."

The family's heartache began last year when Edward became ill.

His parents had no idea he had inherited the fatal disorder, which leaves its victim with reduced antibodies leaving them helpless to fight off disease.

Alyson said: "To look at him you would never have known anything was wrong with him and it's the same with Alex."

After seeing several doctors Edward was diagnosed with the condition aplastic anaemia and was given a course of drugs.

But the treatment failed and Edward was forced to have a transplant with bone marrow donated from his dad.

The transplant was unsuccessful, and after undergoing months of painful chemotherapy and radiotherapy Edward underwent a second operation.

It was then that doctors discovered Edward had the antibody deficiency disorder XLP.

Sadly, despite a hard-fought battle, the youngster lost his fight for life.

Alyson said: "Bonfire night was the last night Edward spent at home. After that he spent his life in hospital."

Dad, Ian, 36, a farmer, said: "To see your son die is the worst thing that can possibly happen to a father. But to find out your other son has the same condition leaves me with heartache I can't even begin to describe."

But the couple have been given a glint of hope after discovering that their other son Michael, nine, is a perfect bone marrow match to Alex.

Alex is given antibodies every three weeks to boost his immune system before his transplant in the autumn.