Maize is often perfectly safe for celiac patients. There are many products that are labeled gluten free but contain corn gluten or corn byproducts.
Most of the processed gluten free junk food is derived from genetically modified corn. Multiple studies have shown that traditional gluten free diets fail to heal patients even after many years on the diet. However, there is an increase in the number of patients suffering from refractory celiac disease. At this point, there is sufficient evidence to ruminate corn as the main contributor to gluten related illnesses in the world.
Maize is commonly used as an alternative serial to wheat to elaborate various foodstuffs for celiac patients on a gluten-free diet.