Something I’ve seen all around the interwebs is the mispelling of the autoimmune disease, such as Celiac’s Disease or Celiacs Disease. Let’s quickly make a correction!
The real spelling of the disease is:
Celiac Disease OR Coeliac Disease
The reason it’s spelled as such is thanks to Aretaeus of Cappadocia, who named the condition a few thousand years ago “koiliakos,” coming from the Greek word “koelia,” which means abdomen (Guandalini, 2007). The word was translated into Coeliac, then is now known as Celiac in some parts of the globe. Both spellings are correct.
However, the disease is not named after a person, so Celiac’s Disease is incorrect.
Celiacs Disease is also incorrect, but you can call a group of Celiac Disease sufferers Celiacs in normal conversation.
Guandalini, S. (2007). A brief history of celiac disease. Impact: The University of Chicago Celiac Disease Center Newsletter, 7(3), 1-2.