A family with atypical Hailey Hailey disease--is there more to the underlying genetics than ATP2C1?

The role of the ATP2C1 gene in Hailey-Hailey disease

Hailey-Hailey disease (HHD) is a rare autosomal dominant acantholytic dermatosis, characterized by a chronic course of repeated and exacerbated skin lesions in friction regions. The pathogenic gene of HHD was reported to be the ATPase calcium-transporting type 2C member 1 gene (ATP2C1) located on chromosome 3q21-q24. Its function is to maintain normal intracellular concentrations of Ca2+/Mn2+ by transporting Ca2+/Mn2+ into the Golgi apparatus. ATP2C1 gene mutations are reportedly responsible for abnormal cytosolic Ca2+/Mn2+ levels and the clinical manifestations of HHD. Environmental factors and genetic modifiers may also affect the clinical variability of HHD. This article aims to critically discuss the clinical and pathological features of HHD, differential diagnoses, and genetic and functional studies of the ATP2C1 gene in HHD. Further understanding the role of the ATP2C1 gene in the pathogenesis of HHD by genetic, molecular, and animal studies may contribute to a better clinical diagnosis and provide new strategies for the treatment and prevention of HHD.

ATP2C1 gene mutations in Hailey-Hailey disease and possible roles of SPCA1 isoforms in membrane trafficking

ATP2C1 gene codes for the secretory pathway Ca(2+)/Mn(2+)-ATPase pump type 1 (SPCA1) localizing at the golgi apparatus. Mutations on the human ATP2C1 gene, causing decreased levels of the SPCA1 expression, have been identified as the cause of the Hailey-Hailey disease, a rare skin disorder. In the last few years, several mutations have been described, and here we summarize how they are distributed along the gene and how missense mutations affect protein expression. SPCA1 is expressed in four different isoforms through alternative splicing of the ATP2C1 gene and none of these isoforms is differentially affected by any of these mutations. However, a better understanding of the tissue specific expression of the isoforms, their localization along the secretory pathway, their specific binding partners and the role of the C-terminal tail making isoforms different from each other, will be future goals of the research in this field.

Papular acantholytic dyskeratosis of the anogenital and genitocrural area: case series and review of the literature

BACKGROUND

Papular acantholytic dyskeratosis (PAD) of the anogenital/genitocrural area is described as a rare distinct clinicopathological entity known to dermatopathologists, although its characteristic histopathologic pattern resembles both Hailey-Hailey disease and Darier disease. The objective of this study is to describe the clinical characteristics, histopathologic features and response to treatment of PAD.

METHODS

We report in detail six cases of PAD. A literature search of the keyword 'papular acantholytic dyskeratosis' was performed on Google scholar and PubMed, 21 cases of this entity were found. A total of 27 patients including our six cases are reviewed in this study.

RESULTS

The mean age at diagnosis was 38.8 years with a male to female ratio of 0.8 : 1. Clinically, papular lesions (55.6%) are the typical manifestation of PAD, and the anogenital area (63%) is the most commonly involved site. Lesions were resistant to topical steroids, subcutaneous interferon and antibiotics while one case showed complete resolution of the lesions after retinoid therapy. Laser therapy showed good results in one case. None of the patients had spontaneous remission.

CONCLUSION

Awareness of the clinicopathological hallmarks herein may be important to avoid underdiagnosis of PAD and may contribute to understanding the pathogenesis of this rare disease.