Mast Cell Activation in Dowling-Degos disease.

Dowling-Degos disease (DDD OMIM 179850) is a rare autosomal-dominant genodermatosis in the spectrum of reticulate pigmented anomalies that usually presents after puberty. It is characterised by reticulate hyperpigmentation and small brownish papules, located at various regions depending on the mutation. Loss-of-function mutations in the genes KRT5, POGLUT1, POFUT1 and PSENEN were identified for DDD. Patients with KRT5 mutations usually develop their lesions at intertriginous areas, whereas patients with POGLUT1 often show affected extremities. Histology reveals downward elongations of rete ridges with a reticulated or fenestrated pattern, occasional horn cysts and basal hyperpigmentation. The phenotype depends on the affected gene. This article is protected by copyright. All rights reserved.