High frequency of the PPOX p.Arg168His pathogenic variant among Brazilian patients with variegate porphyria.

INTRODUCTION: Variegate Porphyria (VP) is the predominant porphyria in South Africa, historically linked to Dutch colonization, and is considered the second most common AHP. Data from Brazil remain scarce. This study aimed to describe the genetic findings in a case series of Brazilian VP patients. METHODS: We conducted a cross-sectional study including patients with VP from three different Brazilian tertiary centers. Medical records and previous genetic testing reports from commercial kits were reviewed and presented including literature review. RESULTS: A total of 35 patients from 19 families were identified. Twenty-three of these had experienced acute attacks, with first symptoms presenting between 17 and 62 years of age. All patients initially presented abdominal pain, and 20 developed severe attacks followed by acute flaccid paralysis. Genetic analysis revealed that fourteen (74%) families carried the same missense variant in exon 6 of PPOX gene (p.Arg168His). CONCLUSION: We describe the first case series of Brazilian VP patients with a recurrent variant p.Arg168His that may suggest a regional founder effect or uncharacterized ancestral links, which warrant further genetic and epidemiological studies.