TGM2 and diabetes mellitus: Children with type 1 diabetes mellitus (T1DM) are at increased risk of coeliac disease (CD) compared with the general population.1 According to current guidance, serological screening for CD is recommended at T1DM diagnosis for adults and children and at ‘regular intervals’ thereafter, although frequency is not specified.2 Current practice involves measuring levels of coeliac-related antibodies, most commonly anti-tissue transglutaminase (TTG) and antiendomysial antibodies.