846 A new case series of olmsted syndrome subjects confirms EGFR activation and long term efficacity of oral erlotinib with acceptable tolerance

Abstract

Olmsted syndrome (OS) is a rare, painful and severe form of palmoplantar keratoderma (PPK). It is most often caused by dominant mutations in the transient receptor potential vanilloid-3 (TRPV3) gene, a heat-sensitive ion channel that forms a signaling complex with the epidermal growth factor receptor (EGFR). TRPV3 mutations are thought to activate EGFR causing abnormal keratinocyte proliferation and differentiation. We previously reported that blocking EGFR with oral Erlotinib resulted in remarkable improvement in 4 young patients.