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Olmsted syndrome (OS) is a rare genodermatosis classically characterized by the combination of bilateral mutilating transgredient palmoplantar keratoderma (PPK) and periorificial keratotic plaques, but which shows considerable clinical heterogeneity. The disease starts usually at birth or in early childhood. About 73 cases have been reported worldwide. OS is observed in both sexes, although male cases are more frequent. The most suggestive symptoms associate PPK with pseudoainhum and periorificial keratotic plaques. Frequently associated features include hair and nail abnormalities, leukokeratosis, corneal default and recurrent infections. Pain and itching are variable but can be severe. Most of reported OS cases are sporadic, although familial cases with different mode of inheritance were also described. Mutations in TRPV3 (Transient receptor potential vanilloid-3) gene have recently been identified as a cause of autosomal dominant (gain-of-function mutations) or recessive OS. Mutations in MBTPS2 (membrane-bound transcription factor protease, site 2) gene were identified in a recessive X-linked form. The diagnosis relies mainly on clinical features associating severe PPK and periorificial keratotic plaques, but can be challenging in patients with incomplete phenotype or atypical features. OS has to be differentiated from other severe forms of PPK including Vohwinkel, Clouston, Papillon-Lefèvre or Haim-Munk syndromes, Mal de Meleda, pachyonychia congenita, Tyrosinemia type II and acrodermatitis enteropathica. When differential diagnoses are difficult to exclude, genetic studies are essential to search for a TRPV3 or MBTPS2 mutation. However, additional genes remain to be identified. No specific and satisfactory therapy is currently available for OS. Current treatments of hyperkeratosis (mainly emollients, keratolytics, retinoids or corticosteroids), either topical or systemic, are symptomatic and offer only temporary partial relief. Specific management of pain and itching is important to reduce the morbidity of the disease. The disease is debilitating and progressive keratoderma and auto-amputation of digits can prevent patients from grasping and walking, and confine them to a wheelchair. New therapeutic options are therefore crucial and are expected from a better understanding of the disease mechanisms. The use of TRPV3 antagonists would represent such a targeted and potentially powerful strategy. Olmsted syndrome (OS) is a rare genodermatosis classically characterized by the combination of bilateral mutilating transgredient palmoplantar keratoderma (PPK) and periorificial keratotic plaques, but which shows considerable clinical heterogeneity. The disease starts usually at birth or in early childhood. About 73 cases have been reported worldwide. OS is observed in both sexes, although male cases are more frequent. The most suggestive symptoms associate PPK with pseudoainhum and periorificial keratotic plaques. Frequently associated features include hair and nail abnormalities, leukokeratosis, corneal default and recurrent infections. Pain and itching are variable but can be severe. Most of reported OS cases are sporadic, although familial cases with different mode of inheritance were also described. Mutations in TRPV3 (Transient receptor potential vanilloid-3) gene have recently been identified as a cause of autosomal dominant (gain-of-function mutations) or recessive OS. Mutations in MBTPS2 (membrane-bound transcription factor protease, site 2) gene were identified in a recessive X-linked form. The diagnosis relies mainly on clinical features associating severe PPK and periorificial keratotic plaques, but can be challenging in patients with incomplete phenotype or atypical features. OS has to be differentiated from other severe forms of PPK including Vohwinkel, Clouston, Papillon-Lefevre or Haim-Munk syndromes, Mal de Meleda, pachyonychia congenita, Tyrosinemia type II and acrodermatitis enteropathica. When differential diagnoses are difficult to exclude, genetic studies are essential to search for a TRPV3 or MBTPS2 mutation. However, additional genes remain to be identified. No specific and satisfactory therapy is currently available for OS. Current treatments of hyperkeratosis (mainly emollients, keratolytics, retinoids or corticosteroids), either topical or systemic, are symptomatic and offer only temporary partial relief. Specific management of pain and itching is important to reduce the morbidity of the disease. The disease is debilitating and progressive keratoderma and auto-amputation of digits can prevent patients from grasping and walking, and confine them to a wheelchair. New therapeutic options are therefore crucial and are expected from a better understanding of the disease mechanisms. The use of TRPV3 antagonists would represent such a targeted and potentially powerful strategy. [ABSTRACT FROM AUTHOR]

Background: Olmsted syndrome is a rare congenital skin disorder presenting with periorifical hyperkeratotic lesions and mutilating palmoplantar keratoderma, which is often associated with infections of the keratotic area. A recent study identified de novo mutations causing constitutive activation of TRPV3 as a cause of the keratotic manifestations of Olmsted syndrome. Methods: Genetic, clinical and immunological profiling was performed on a case study patient with the clinical diagnosis of Olmsted syndrome. Results: The patient was found to harbour a previously undescribed 1718G-C transversion in TRPV3, causing a G573A point mutation. In depth clinical and immunological analysis found multiple indicators of immune dysregulation, including frequent dermal infections, inflammatory infiltrate in the affected skin, hyper IgE production and elevated follicular T cells and eosinophils in the peripheral blood. Conclusions: These results provide the first comprehensive assessment of the immunological features of Olmsted syndrome. The systemic phenotype of hyper IgE and persistent eosinophilia suggest a primary or secondary role of immunological processes in the pathogenesis of Olmsted syndrome, and have important clinical consequences with regard to the treatment of Olmsted syndrome patients. [ABSTRACT FROM AUTHOR]