Identification of Several Mutations in ATP2C1 in Lebanese Families: Insight into the Pathogenesis of Hailey-Hailey Disease

Abstract

BackgroundHailey-Hailey disease (HHD) is an inherited blistering dermatosis characterized by recurrent erosions and erythematous plaques that generally manifest in intertriginous areas. Genetically, HHD is an autosomal dominant disease, resulting from heterozygous mutations in ATP2C1, which encodes a Ca2+/Mn2+ATPase. In this study, we aimed at identifying and analyzing mutations in five patients from unrelated families diagnosed with HHD and study the underlying molecular pathogenesis.ObjectivesTo genetically study Lebanese families with HHD, and the underlying molecular pathogenesis of the disease.MethodsWe performed DNA sequencing for the coding sequence and exon-intron boundaries of ATP2C1. Heat shock experiments were done on several cell types. This was followed by real-time and western blotting for ATP2C1, caspase 3, and PARP proteins to examine any possible role of apoptosis in HHD. This was followed by TUNEL staining to confirm the western blotting results. We then performed heat shock experiments on neonatal rat primary cardiomyocytes.ResultsFour mutations were detected, three of which were novel and one recurrent mutation in two families. In order for HHD to manifest, it requires both the genetic alteration and the environmental stress, therefore we performed heat shock experiments on fibroblasts (HH and normal) and HaCaT cells, mimicking the environmental factor seen in HHD. It was found that stress stimuli, represented here as temperature stress, leads to an increase in the mRNA and protein levels of ATP2C1 in heat-shocked cells as compared to non-heat shocked ones. However, the increase in ATP2C1 and heat shock protein hsp90 is significantly lower in HH fibroblasts in comparison to normal fibroblasts and HaCaT cells. We did not find a role for apoptosis in the pathogenesis of HHD. A similar approach (heat shock experiments) done on rat cardiomyocytes, led to a significant variation in ATP2C1 transcript and protein levels.ConclusionThis is the first genetic report of HHD from Lebanon in which we identified three novel mutations in ATP2C1 and shed light on the molecular mechanisms and pathogenesis of HHD by linking stress signals like heat shock to the observed phenotypes. This link was also found in cultured cardiomyocytes suggesting thus a yet uncharacterized cardiac phenotype in HHD patients masked by its in-expressivity in normal health conditions.

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

“…Few nonsense mutations were frequently reported in different families worldwide (reports with at least three cases): 115 C > T causing R39X; 6, 18, 19 457 C > T causing R153X; 7, 20, 21, 22, 23, 24, 25 1402 C > T causing R468X; 7, 26, 27, 28 1516 C > T causing Q506X; 29, 30 and 2395 C > T causing R799X. 18, 25, 31, 32, 33, 34 The above single residues represent ‘hotspots' for mutations, and notably, they all occur at CpG sites where the possibility of mutations is higher.…”

Four novel ATP2C1 mutations in Chinese patients with Hailey–Hailey disease

“…In conclusion, HHD is a hereditary blistering skin disease characterized by episodic maceration and erosions mainly in intertriginous areas. Because the ATP2C1 gene was identified as the pathogenic gene of HHD, more than 150 mutations in the ATP2C1 gene have been reported, including nonsense, missense, frame‐shift and splice‐site mutations …”

“…Because the ATP2C1 gene was identified as the pathogenic gene of HHD, more than 150 mutations in the ATP2C1 gene have been reported, including nonsense, missense, frame-shift and splice-site mutations. [1][2][3][4][5][6][7][8][9][10][11][12][13] Generally, direct mutation analysis is the most powerful and conclusive means of molecular diagnosis. In our study, five different heterozygous mutations of ATP2C1 were identified in HHD patients in the four pedigrees and two sporadic cases.…”

A Case of Hailey-Hailey Disease with a Novel Nonsense Mutation in the ATP2C1 Gene

“…We recently reported that the severe phenotype of a case with a PT-causing mutation is possibly caused by nonsense-mediated mRNA decay 3 . To confirm this possibility in the present case, ATP2C1 mRNA expression was examined with reverse transcription-polymerase chain reaction (RT-PCR) using mRNA extracted from the biopsy specimen and ATP2C1 -specific primer pairs which amplify an upstream portion of the mutation described elsewhere 4 . Biopsy specimen of the lesional skin from a patient with urticarial rash was simultaneously examined for the control.…”