There are two types of mustard plant with defined allergens, Oriental Mustard and Yellow Mustard.
Oriental mustard only contains one allergen, Bra j 1, which is a 2S seed storage protein commonly found in nuts and seeds.
Yellow mustard has 4 food allergens.
Sin a 1 is also a 2S seed storage protein and Sin a 2 is an 11S seed storage protein.
Sin a 3 is a lipid transfer protein (LTP) and Sin a 4 is a profilin protein.
Yellow mustard allergy can be linked to LTP Syndrome, where similarly shaped proteins in other plants resemble those in mustard and elicit an allergic reaction.
Other food containing 2S albumin seed storage proteins are cashews, peanuts, brazil nuts, turnips, rapeseed, pecans, chickpeas, hazelnuts, pistachio, buckwheat, soya, sunflower seeds, walnuts, kiwi, castor beans and sesame seeds.
Other food containing 11S proteins (not already mentioned above) are pumpkins, walnuts and almonds.
If sensitised to Lipid Transfer Proteins you may also have allergic reactions to almonds, hazelnuts, cabbage, walnuts, apples, dried fruit, lettuce and tomatoes.