Eficácia da dapsona em dois casos de dermatomiosite amiopática Efficacy of dapsone in two cases of amyopathic dermatomyositis

A dapsona é uma droga utilizada no tratamento da hanseníase que vem sendo empregada em casos de lúpus eritematoso bolhoso e alguns tipos de vasculites cutâneas. Recentemente, foi observada sua eficácia no tratamento de lesões cutâneas da dermatomiosite. São apresentados dois casos de dermatomiosite, forma amiopática, refratários às medicações habituais, em que o uso de dapsona foi responsável pelo controle das lesões cutâneas.<br>Dapsone is a drug primarily used for the treatment of Hansen’s disease, and it has also been employed in cases of bullous lupus erythematosus and some types of cutaneous vasculitis. Recently, its efficacy in the treatment of cutaneous lesions in dermatomyositis has been observed. We present two cases of dermatomyositis, amyopathic form, which were refractory to habitual treatment, but had an excellent response to dapsone therapy

Haploinsufficiency for AAGAB causes clinically heterogeneous forms of punctate palmoplantar keratoderma

Palmoplantar keratodermas (PPKs) are a group of disorders that are diagnostically and therapeutically problematic in dermatogenetics(1-3). Punctate PPKs are characterized by circumscribed hyperkeratotic lesions on palms and soles with considerable heterogeneity. In 18 families with autosomal dominant punctate PPK (OMIM #148600), we report heterozygous loss-of-function mutations in AAGAB, encoding alpha- and gamma-adaptin binding protein p34, at a previously linked locus on 15q22. p34, a cytosolic protein with a Rab-like GTPase domain, was shown to bind both clathrin adaptor protein complexes, indicative of a role in membrane traffic. Ultrastucturally, lesional epidermis showed abnormalities in intracellular vesicle biology. Immunohistochemistry showed hyperproliferation within the punctate lesions. Knockdown of p34 in keratinocytes led to increased cell division, which was linked to greatly increased epidermal growth factor receptor (EGFR) protein expression and tyrosine phosphorylation. We hypothesize that p34 deficiency may impair endocytic recycling of growth factor receptors such as EGFR, leading to increased signaling and proliferation