New Zealand Organisation for Rare Disorders chief executive Dr Collette Bromhead, a molecular biologist, said studies had shown an association between exposure to silica, found in many types of rock, and scleroderma although there was not yet any conclusive proof it was a cause of the disease.
"I certainly think that this man, given that he was a stonemason, he potentially has industrial exposure," he said.
Fabian confirmed he too had been told there was a possibility his years working with rock could have caused the disease.
Bromhead said if a person had a genetic pre-disposition to the disease, exposure to a mineral like silica could be all that was needed for it to develop.
Massey University senior lecturer in environmental chemistry Dr Nick Kim confirmed stonemasons could be "industrially exposed to significant levels of silica".
Bromhead said scleroderma was a disease routinely tested for in auto-immune screenings but Fabian had the nastiest and rarest form.
Some people just developed patches of it and could lead a very normal life, she said.
"His is a case in a million really," she said. "It's devastating."
Since the Herald reported on Fabian's plight last night, more than $15,000 had been donated via a Give a Little page set up for him by Scleroderma Auckland.
Fabian said he was amazed by the generosity.
"I can't believe that's happened. No one's ever given me anything," he said. "Thank you very, very much. Getting the word out on scleroderma is very important for me. I want people to understand it. There are people suffering out there who don't realise they've got it."
RSA district support adviser for the Auckland region Ray Farrell, who visits Fabian every day, said he too was blown away by the amount of support he had received since the story was published.
"We've been amazed with the amount of calls coming in this morning," he said.
Other divisions of the RSA had also offered to help wherever they could.