Inborn errors of immunity (IEI) often present with gastrointestinal symptoms, which may be the first manifestation of immunological abnormalities. The second segment of this review is a supplement to the description of diseases classified by the International Union of Immunological Societies (IUIS) as primary immunodeficiencies, characterised by a specific clinical picture related to the gastrointestinal system. The article presents the current state of knowledge, discussing diagnostic, pathophysiological, and therapeutic aspects, emphasising the importance of multidisciplinary cooperation in the treatment of these complex cases.
