Severe peripheral neuropathy secondary to acute intermittent porphyria caused by a rare HMBS gene mutation: a case report

BACKGROUND: Peripheral neuropathy is caused by numerous etiologies, such as immune, infectious, neoplastic, metabolic, toxic, traumatic, vasculitic, hereditary factors, etc. Each etiological type has no special manifestation, and the misdiagnosis rate is relatively high. Acute intermittent porphyria (AIP) is a rare disease, often complicated by peripheral nerve injury, and can develop sequelae after delayed diagnosis or treatment. CASE PRESENTATION: A 26-year-old female patient presented with recurrent abdominal pain, limb numbness and weakness, and autonomic neuropathy. Symptoms aggravated and respiratory and circulatory failure develop gradually, following the recurrence of the disease. She was initially diagnosed with neurosis, intestinal obstruction, and Guillain-Barré syndrome. She underwent treatment for inflammatory peripheral neuropathy, including intravenous immunoglobulin (IVIG) and plasmapheresis; however, no improvement in symptoms was observed. Clinical assessment revealed brown urine that turned reddish-brown after sunlight exposure. Whole exome sequencing (WES) identified a mutation in the HMBS gene (exon 10, c.651G > C, p.Gln217His), which was confirmed through Sanger sequencing and diagnosed as rare AIP with severe peripheral nerve damage. Numbness and weakness gradually improved after the initiation of hemin therapy and high-carbohydrate therapy. CONCLUSION: The AIP is an easily missed or misdiagnosed disease. In the absence of timely and effective intervention, patients are at risk of developing irreversible and permanent neurological damage. It is essential for clinicians to enhance their awareness of the disease to ensure prompt diagnosis, appropriate treatment, and avoidance of triggering factors.