According to our data, in order to define the form of AD, it might be sufficient to determine only one parameter between sIgE and SPT, excluding total IgE[43]: certainly, sIgE are more sensitive, in particular for inhalant allergens in the first years of life, but in our study when only SPT were performed, the patients distribution between IgE and non-IgE-associated AD did not change, because of multiple inhalant and/or food sensitizations in the majority of children. The gene discussed is IGHE; the disease is Alzheimer disease.