A Particular Case of Autosomal Recessive Progressive Symmetrical Erythrokeratodermia (PSEK) and a Review of the Literature.

Abstract: Case report A A 10-year-old female patient born from non-consanguineous healthy parents after a regular pregnancy developed, at the age of 3 months, diffuse hyperkeratotic, pruritic plaques on her face, forearms, wrists, perineal and sacral regions in a mosaic pattern distribution, growing progressively. Laboratory and instrumental investigations and a skin biopsy were performed, and both the patient and her parents underwent genetic testing. Histology described acanthosis and orthokeratotyc hyperkeratosis in a basket-weave pattern. Genetic investigations revealed, in our patient, a pathogenic paternal variant and the deletion of the corresponding maternal allele associated with the autosomal recessive form of Progressive Symmetrical Erythrokeratodermia (PSEK). Discussion A review of the literature showed similarities and differences with this case. Diagnosis of autosomal recessive PSEK was made, uniquely associated in our patient with another genetic mutation of the KRT2 gene. Systemic retinoids and topical emollients were started, leading to a significant reduction of hyperkeratosis and a progressive resolution of the lesions. The most interesting feature was their further evolution, with the onset of sparing areas, suggestive of revertant mosaicism, although not confirmed by histology. Conclusion This is the first case of Progressive Symmetrical Erythrokeratodermia associated with both the c.879G>A genomic variant in the KDSR gene and the p.Ala517Gly genetic variant of the KRT2 gene. A clinical picture was suggestive of revertant mosaicism observed in the patient, which, to date, has never been described in the literature. Systemic therapy with oral retinoids in association with topical keratolytics.