There are two key food allergens found in macadamia nuts, Mac i 1 and Mac i 2.
Mac i 1 is a vicilin like protein used in storage in the plant. This is also sometimes described as a 7S seed storage protein.
Mac i 2 is a legumin like protein, this is similar to the protein casein in milk. This is also often described as an 11S seed storage protein.
Macadamia nut allergy is not currently linked to any allergic syndromes.
Other foods containing vicilin like proteins are cashew, pecan, hazelnuts, buckwheat, soyabean, walnut, lentil, lupin, peas, sesame and mung bean.
There is a lot of crossover between foods containing vicilin and those containing legumin proteins. Foods containing legumin but not vicilin proteins are peanut, almond and mustard.