Curious case of missing (A) in coeliac disease with type 1 diabetes mellitus

Coeliac screening in type 1 diabetes mellitus (T1DM) is universally recommended, but not all authorities recommend serum IgA estimation before using an IgA-based test. We report a case of T1DM with poor glycaemic control and recurrent episodes of hypoglycaemias and diabetic ketoacidosis (DKA). Recurrent oromucosal and respiratory infections further complicated the course of illness, resulting in the increasing proneness to DKA. The patient was screened for coeliac disease but the IgA-based screening test was negative (IgA tissue transglutaminase) due to the low IgA level, whereas the IgG antigliadin was positive. The patient benefited from initiation of a gluten-free diet.