Case report: Novel p.Val306Met missense mutation in TRPV3 in a case of Olmsted syndrome accompanied by squamous cell carcinoma

Olmsted syndrome (OS) is a rare congenital skin disorder, typically characterized by symmetrical, severe palmoplantar and periorificial keratoderma, often accompanied by alopecia, and onychodystrophy, with varying degrees of pruritus and pain. Gain-of-function variants of the transient receptor potential cation channel subfamily V member 3 (<i>TRPV3</i>) were described as a cause of OS. Here, we report an atypical case of OS caused by a novel mutation in the <i>TRPV3</i> gene that has not been described before in OS. The patient presented with disabling, bilateral palmoplantar keratoderma, and subsequently developed squamous cell carcinoma on the right sole. Genetic analysis identified a novel heterozygous p.Val306Met missense mutation in the exon 8 of <i>TRPV3</i>. Our findings expand the phenotypic spectrum of <i>TRPV3</i>-related OS and underscore the need for vigilant long-term monitoring of these patients.