Systematic mutation screening of KRT5 supports the hypothesis that Galli-Galli disease is a variant of Dowling-Degos disease.

[malignant atrophic papulosis]

Galli-Galli disease (GGD ) is a rare genodermatosis . Its clinical presentation is identical to that of Dowling-Degos disease (DDD ), but the presence of the histopathological feature of acantholysis in GGD is thought to distinguish the two disorders . Mutations in the keratin 5 gene (KRT 5 ) have been identified in the majority of patients with DDD and in a small number of patients with GGD .To provide further support for the hypothesis that GGD is merely a variant of DDD , and to examine whether acantholysis is genuinely rare in DDD or rather a common but under-reported histological feature of DDD .We conducted the first systematic mutational investigation of patients with GGD and re -examined the histopathology of patients previously assigned a diagnosis of DDD . For the mutational investigation , KRT 5 was sequenced in seven unrelated patients with clinically and histopathologically confirmed GGD . In addition , the histopathological findings of six patients with DDD were re -evaluated .The mutation c .418 dupA was found in five patients with GGD . The typical histopathological features of GGD were identified in six patients who had previously been assigned a diagnosis of DDD .We found further evidence to suggest that GGD is indeed a variant of DDD and not a distinct disease entity . Two facts in particular support this conclusion : the same KRT 5 mutation was found in patients with GGD and in patients with DDD , and acantholysis seems to be present in a large number of patients who had previously been assigned a diagnosis of DDD .