Inclusion Criteria:  CD will be diagnosed according to the current guidelines. In details, the following standard criteria will be adopted to diagnose CD ("4 out of 5" rule):  gluten/wheat-dependent symptoms, both intestinal and extraintestinal positivity of anti-deamidated gluten peptides (DPG) IgA and IgG antibodies, anti-transglutainase (tTG) IgA and IgG antibodies, and endomysium antibodies (EMA) presence of crypt hyperplasia and duodenal villous atrophy on duodenal biopsy presence of HLA haplotypes DQ2 and/or DQ8 resolution of symptoms with a rigorous GFD  Additional inclusion criteria, both for the retrospective and prospective part of the study, will be:  age >18 and <65 years complete clinical records clinical and laboratory follow-up of at least one year from diagnosis -  Exclusion Criteria:  age <18 and >65 years incomplete medical records lack of clinical and laboratory follow-up of at least one year from diagnosis pregnancy alcohol and/or drug abuse diagnosis of IBD or other gastrointestinal organic disease