RESUMO
Autosomal-dominant diffuse nonepidermolytic palmoplantar keratoderma is characterized by the adoption of a white, spongy appearance of affected areas upon exposure to water. After exome sequencing, missense mutations were identified in AQP5, encoding water-channel protein aquaporin-5 (AQP5). Protein-structure analysis indicates that these AQP5 variants have the potential to elicit an effect on normal channel regulation. Immunofluorescence data reveal the presence of AQP5 at the plasma membrane in the stratum granulosum of both normal and affected palmar epidermis, indicating that the altered AQP5 proteins are trafficked in the normal manner. We demonstrate here a role for AQP5 in the palmoplantar epidermis and propose that the altered AQP5 proteins retain the ability to form open channels in the cell membrane and conduct water.
Assuntos
Aquaporina 5/genética , Membrana Celular/metabolismo , Epiderme/metabolismo , Ceratodermia Palmar e Plantar Difusa/genética , Mutação , Punho/fisiopatologia , Sequência de Bases , Epiderme/fisiopatologia , Genes Dominantes , Humanos , Ceratodermia Palmar e Plantar Difusa/fisiopatologia , Modelos Moleculares , Dados de Sequência Molecular , Linhagem , Transporte Proteico , Água/metabolismoRESUMO
Una mujer de 50 años presentaba cientos de pequeñas lesiones papulosas hiperqueratósicas distribuidas por el tronco y la zona proximal de extremidades, sin afectación palmoplantar ni de los anejos cutáneos. Al microscopio las lesiones mostraban hiperqueratosis ortoqueratósica. La hiperqueratosis digitada diminuta múltiple tiene varias formas de presentación: familiar (con inicio en la segunda y tercera década de la vida), esporádica y postinflamatoria. El estudio histopatólogico demuestra que las formas familiares y esporádicas tienen características semejantes, diferentes de las formas postinflamatorias. (AU)
