Among the 44 individuals carrying a mutation in the PBGD gene, eight (18%) were classified with active disease (AIP-AD) as defined by high urinary porphyrin precursor excretion (ALA, ≥7.5 mmol/mol creat.; PBG, ≥3.4 mmol/mol creat). Here, HMBS is linked to autoimmune pancreatitis.