Novel Variant and a Possible New Founder Effect for Xeroderma Pigmentosum Variant Type in Southeast Brazil: Case Report.

INTRODUCTION

Xeroderma pigmentosum (XP) is a group of genodermatoses with autosomal recessive inheritance, comprising 9 subtypes designated A to J plus a variant (V) type, clinically characterized by increased photosensitivity, with specific subtypes more prone to ocular disease and progressive neurodegeneration.

CASE PRESENTATION: Three patients with the XP-V variant, a pair of sisters and an unrelated individual, presented with a novel homozygous c.1245-1G>A intronic splice site variant in the POLH gene classified as likely pathogenic. They exhibited numerous freckles and hypo- and hyperpigmented lesions that evolved into basal cell and squamous cell carcinomas, as well as thin malignant melanocytic lesions, photophobia, conjunctival telangiectasis, ectropion, and pterygia, without neurological symptoms.

CONCLUSION

The possibility of dealing with a new founder effect for this specific variant in the State of Minas Gerais, in the Southeast region of Brazil, is suggested.