My boyfriend can’t feel the burn

Patient: My boyfriend doesn’t get the burn that most people do off of foods like horseradish, wasabi, or mustard. He does taste the spice off of things like jalapenos and other peppers, though. I’ve also noticed he has unusually thick and mucus-y saliva, even though he stays well hydrated. I was wondering why he can’t feel the burn and if it is related to the consistency of his saliva.

Doctor: