Effects of diabetes mellitus on patients with acute intermittent porphyria

Objectives. To study the effects of diabetes mellitus in patients with acute intermittent porphyria (AIP). Haeme deficiency in the liver of AIP patients stimulates an increase in ALA-synthase which triggers an escalating metabolic chain reaction, leading to an increase in the porphyrin content. This reaction can be reduced by treating AIP patients with haeme arginate or with glucose. Design. A population-based study of all patients >18 years of age having DNA-verified AIP (n = 328) living in the two most northerly counties of Sweden (Norrbotten and Vasterbotten, with 550 000 inhabitants) of whom 16 had type 2 diabetes. Prevalence of diabetes was studied retrospectively in 26 AIP patients with hepatocellular carcinoma (HCC). Results. None of the patients showed symptoms of AIP after the onset of their diabetes. Three patients had had recurrent, severe attacks for many years but when their diabetes became manifest, their urinary ALA and PBC levels decreased and the AIP symptoms resolved, to the relief of the patients. Amongst the 26 AIP patients with HCC, only one with signs of diabetes was identified (impaired glucose tolerance test). Conclusions. This study raises the possibility that diabetes mellitus may be beneficial for patients with severe AIP.