Thus, the most frequent clinical manifestations of non-IgE-mediated CMPA in breastfed infants are mainly gastrointestinal, such as regurgitation, colic, and irritability, and skin clinical manifestation, such as atopic dermatitis [31], whereas severe reactions, such as severe atopic eczema or protein-losing enteropathy, are extremely rare [45]. The gene discussed is IGHE; the disease is Protein-losing enteropathy.