title: Identification of several mutations in ATP2C1 in Lebanese families: insight into the pathogenesis of Hailey-Hailey disease.
abstract: BACKGROUND
  Hailey-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.
  
  
  OBJECTIVE
  To genetically study Lebanese families with HHD, and the underlying molecular pathogenesis of the disease.
  
  
  METHODS
  We 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.
  
  
  RESULTS
  Four 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.
  
  
  CONCLUSIONS
  This 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.
authors: Department of Dermatology, American University of Beirut, Beirut, Lebanon.
authors: Waed
authors: W
authors: Btadini
authors: Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon.
authors: Ossama K
authors: OK
authors: Abou Hassan
authors: Department of Dermatology, American University of Beirut, Beirut, Lebanon.
authors: Dana
authors: D
authors: Saadeh
authors: Department of Dermatology, American University of Beirut, Beirut, Lebanon.
authors: Ossama
authors: O
authors: Abbas
authors: Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon.
authors: Farah
authors: F
authors: Ballout
authors: Department of Dermatology, American University of Beirut, Beirut, Lebanon.
authors: Abdul-Ghani
authors: AG
authors: Kibbi
authors: Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon; Department of Pediatrics, American University of Beirut, Beirut, Lebanon.
authors: Ghassan
authors: G
authors: Dbaibo
authors: Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon.
authors: Nadine
authors: N
authors: Darwiche
authors: Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon.
authors: Georges
authors: G
authors: Nemer
authors: Department of Dermatology, American University of Beirut, Beirut, Lebanon; Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon; Department of Dermatology, Columbia University, New York, New York, United States of America.
authors: Mazen
authors: M
authors: Kurban
mesh_terms: D000818:Animals; D000252:Calcium-Transporting ATPases / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D005190:Family; D005260:Female; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D018869:Heat-Shock Response / Q000235:genetics*; D006801:Humans; D007861:Lebanon; D008297:Male; D009154:Mutation; D032383:Myocytes, Cardiac / Q000378:metabolism / Q000473:pathology; D016506:Pemphigus, Benign Familial / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D051381:Rats
chemical_list: C403624:ATP2C1 protein, human; D000252:Calcium-Transporting ATPases