The Fulham parents of a one-year-old boy with an incredibly rare, life-threatening disease need to find a matching donor to save their son's life.

Allesandro Maria Montresor was diagnosed on September 6 with Hemophagocytic Lymphohistiocytosis (HLH), a disease which affects a tiny 0.002% of children and can only be cured by a bone marrow transplant in a short time frame.

Doctors have told Allesandro's parents , Paolo and Cristiana, that he needs a donor as soon as possible but a rare antigen in his bone marrow means he has no matches in the world registry so far.

Now they are campaigning to make more people aware of how to sign up as a donor in the hopes of finding someone who can save their son's life.

Great Ormond Street Hospital main entrance (credit: John Stillwell/PA)

Paolo said: "There are no words to describe how we feel but what I am always telling Cristiana is that though we do not have a healthy boy, at least there is hope.

"There are babies that die because they are never diagnosed or are diagnosed too late and there are babies with even more rare diseases than ours.

"We are definitely not the worst off but it is hard because we are still sitting in uncertainty and do not know what the future will look like for our boy.

"Allesandro is a joyful, happy baby. He never cried, never had a single tear during his months in the hospital. Even with all the needles, he is smiling always.

"That's all we wish for him as his parents, just to have a happy life."

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Allesandro is currently the first UK patient to receive an experimental treatment for HLH, which Paolo reports is "doing great", but the treatment is only predicted to remain effective for a number of weeks.

If a suitable donor cannot be found in time, bone marrow from his parents, each a 50% match, will be used. However, this is far from ideal and means the procedure will have a different and more complex protocol.

Paolo said: "Our campaign to get more people to sign up started as a drop and became a tsunami. Our Facebook page has been seen by hundreds of thousands of people in less than 48 hours.

"We have heard from family, friends and people in the UK and Italy all wanting to know how they can help.

Allesandro, who his father describes as a "joyful, happy baby"

"It's concerning to find people are quite uninformed about the donation of bone marrow. It's no longer a procedure that requires a drill or surgery, now the cells can be taken out of the blood.

"Even if we don't find a match for our son, if we can increase the number of people becoming donors, it will still benefit other sick babies."

Allesandro, who spent two months in St Mary's Hospital after being born at only 30 weeks in March 2017, fell ill on August 23 while on holiday with his parents in Sardinia.

Half the children diagnosed with HLH die within one month of its onset

Doctors in both Italy and the UK said his high fever was caused by a viral infection and would get better with paracetamol.

However, by August 27, his fever was over 40 degrees and spots had appeared on his skin, after which he was admitted to Chelsea and Westminster hospital before being moved to St Mary's.

With the help of Great Ormond's Street Hospital (GOSH), he was quickly diagnosed with HLH and started treatment before the disease was able to spread to his brain and cause irreversible damage.

Paolo said: "He is doing so well that now we have been discharged and only go into GOSH two days a week for the trial.

"We have to keep him at home otherwise because his immune system is shut down but he has all his toys so it is better than being in the hospital.

"There can be a number of complications with the transplant procedure but, if everything goes well, he will be able to conduct a normal life as a normal baby."

You can find more information about how to register to donate bone marrow or stem cells on the NHS website or the DKMS website .