The results showed that AIP patients had decreased numbers of mitochondria and significantly lower serum PERM1 (a marker of mitochondrial biogenesis) levels; a reduction more pronounced in symptomatic patients, suggesting that higher mitochondrial DNA content may modulate porphyria severity or penetrance, perhaps through affecting an individual’s ability to respond to endogenous or environmental stressors. Here, PERM1 is linked to autoimmune pancreatitis.