Papillon–Lefèvre Syndrome Associated with a Newly Identified Homozygous c.872G>A Mutation in the CTSC Gene: A Case Report

Papillon–Lefèvre syndrome (PLS) is a rare autosomal recessive genodermatosis caused by pathogenic variants in the CTSC gene. The condition is characterized by the coexistence of palmoplantar keratoderma and early-onset, rapidly progressive periodontitis. Here, we present a 21-year-old female patient in whom a previously unreported homozygous CTSC variant, c.872G>A, was identified.Since childhood, the patient had marked hyperkeratosis on the palmoplantar regions, early tooth loss, and the need for oral prostheses. A family history of individuals with similar dermatologic features and consanguinity between the parents supported an autosomal recessive inheritance pattern. The identified variant was evaluated in conjunction with the clinical phenotype and was classified as likely pathogenic according to the American College of Medical Genetics and Genomics (ACMG) criteria.Systemic retinoid therapy was recommended but could not be initiated due to patient preference. This case contributes to the expanding genetic spectrum of PLS and highlights the crucial importance of early diagnosis, a multidisciplinary approach, and treatment adherence in determining disease prognosis.