Acute intermittent porphyria caused by novel mutation in HMBS gene, misdiagnosed as cholecystitis

Abstract

Majid Alfadhel,1,3 Neam Saleh,2 Helal Alenazi,2 Henry Baffoe-Bonnie21Division of Genetics, Department of Pediatrics, 2Division of General Medicine, Department of Medicine, King Abdulaziz Medical City, Riyadh, Kingdom of Saudi Arabia; 3College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Kingdom of Saudi ArabiaBackground: Acute intermittent porphyria (AIP) is an autosomal dominant neurovisceral inherited disorder due to a defect in the heme biosynthesis pathway. Misdiagnosis of the porphyrias is not uncommon.Case report: We present a case of a 26-year-old female with suspected acute cholecystitis, mental status changes, and seizures. Biochemical and molecular investigations confirmed the diagnosis of AIP by findings of elevated urinary porphobilinogen, 5-aminolevulinic acid, and total porphyrins. DNA molecular testing showed a novel heterozygous mutation (c. 760delC p.L254X) in the exon11 of the HMBS gene. To the best of our knowledge, this is the first report of a misdiagnosis of AIP presenting with acute cholecystitis.Conclusion: Clinicians are alerted to consider the possibility of AIP in an adult presenting with an acute abdomen, features of cholecystitis, and neuropsychiatric manifestations.Keywords: porphyria, cholecystitis, acute abdomen, acute intermittent porphyria, HMBS gene, hydroxymethylbilane synthase