Mutations of ATP2C1 in Japanese patients with Hailey-Hailey disease: intrafamilial and interfamilial phenotype variations and lack of correlation with mutation patterns

Two novel mutations in the ATP2C1 gene found in Japanese patients with Hailey-Hailey disease

Hailey-Hailey disease (HHD) is an autosomal dominant genodermatosis and the defective gene in HHD is ATP2C1, which encodes secretory pathway Ca²⁺ /Mn²⁺ ATPase type 1 (SPCA1). Here we report four Japanese HHD patients showing three kinds of mutations with premature termination codons in the ATP2C1 gene, including two novel ones. Patient 1 was a 39-year-old man with a novel heterozygous mutation, c.664dup in exon 8 (p.N215Kfs*26). Patient 2 was a 33-year-old man (the younger brother of patient 1) with the same mutation as patient 1. Patient 3 was a 55-year-old man with a previously reported heterozygous mutation, c.519dup in exon 7 (p.R174Tfs*4). Patient 4 was a 33-year-old woman with a novel heterozygous mutation, c.2640del in exon 27 (p.L881Ffs*10). The clinical characteristics of our four cases varied in disease severity and the response to treatment. The present cases enrich the database of mutational analysis for HHD.

Generalized Hailey-Hailey disease: Novel splice-site mutations of ATP2C1 gene in Chinese population and a literature review

BACKGROUND

Hailey-Hailey disease (HHD; OMIM: 169600) is an autosomal dominate genodermatosis, characterized by recurrent blisters and erosions clinically and remarkable acantholysis pathologically. The underlying pathogenic factor is the mutation of ATP2C1 gene (OMIM: 604384), which encodes secretory pathway Ca²⁺ /Mn²⁺ -ATPase (SPCA1). Skin folds are the predilection site of HHD. Atypical cases with a generalized pattern have rarely been reported, making it prone to misdiagnosis.

METHODS

In this study, we presented three Chinese pedigrees of Hailey-Hailey disease with generalized skin lesions. ATP2C1 mutations were screened by DNA sequencing and their transcripts were further confirmed by minigene assay. We also performed a literature review of previously published generalized HHD over past two decades together with our cases.

RESULTS

Three splice-site mutations were identified: c.2487+1G>A, c.2126+1G>A, and c.1891-2A>G, which resulted in an exon 25-truncated transcript, two exon 22-truncated transcripts, and two exon 21-truncated transcripts, respectively. The c.2487+1G>A and the c.1891-2A>G mutations are novel mutations which have not been reported before. No clustered mutations of ATP2C1 gene were found in generalized HHD patients in literature along with our novel mutations.

CONCLUSION

We found no hot spot mutations in ATP2C1 correlated with the generalized pattern of HHD. Our study expanded the spectrum of ATP2C1 mutations, which would be useful for disease diagnosis and genetic counseling.

Hailey-Hailey Disease: An Update Review with a Focus on Treatment Data

Hailey-Hailey disease is a rare blistering dermatosis first described in 1939 by the brothers Howard and Hugh Hailey. Its incidence is estimated at 1/50,000. The inheritance is autosomal dominant with complete penetrance, but a variable expressivity in affected family members. Clinically, Hailey-Hailey disease presents between the third and fourth decade as flaccid vesicles and blisters on erythematous skin, giving rise to erosions, fissures, and vegetations. Maceration and superinfections are frequent. The lesions are typically distributed symmetrically within intertriginous regions such as the retroauricular folds, lateral aspects of the neck, axillae, umbilicus, inguinal, and perianal regions. The disease is characterized by a chronic relapsing course with spontaneous remissions and multiple recurrences. Severe disease can be very frustrating and have a major psychological and social impact. Given the dearth of evidence-based guidelines and large clinical trials, the assessment of the efficacy and safety of treatments is difficult. Treatments include topical and systemic agents, and procedural therapy such as lasers and surgery. This review provides a systematic search of the literature with a focus on classical and emerging treatment options for Hailey-Hailey disease.

A novel splice-site mutation in the ATP2C1 gene of a Chinese family with Hailey-Hailey disease

Hailey-Hailey disease (HHD), also known as familial benign chronic pemphigus, is an autosomal dominant genodermatosis. It is characterized by erosions, blisters and erythematous plaques at sites of friction or intertriginous areas. The pathogenic gene of HHD has been revealed as the ATPase secretory pathway Ca²⁺ transporting 1 gene ( ATP2C1), which encodes the protein, secretory pathway Ca ²⁺/Mn ²⁺-ATPase 1 (SPCA1). ATP2C1 gene mutations are responsible for HHD by resulting in abnormal Ca ²⁺ homeostasis in the skin and giving rise to acantholysis, a characteristic pathology of HHD. In this study, a four-generation family containing three HHD sufferers was recruited. Direct sequencing of the ATP2C1 gene was performed in the proband and other available family members. Reverse-transcriptase polymerase chain reaction analysis was conducted to show the potential variant effect on ATP2C1 splicing. A novel heterozygous c.325-2A>G transition at the splice acceptor site of intron 4 in the ATP2C1 gene was identified, and it co-segregated with the disease in this family. The mutation resulted in exon 5 skipping and an in-frame deletion of 12 amino acids (p.Ala109_Gln120del) in SPCA1. This splice-site mutation may be responsible for HHD in this family. This study would further expand the mutation spectrum of the ATP2C1 gene and may be helpful in the genetic counseling and prenatal diagnosis of HHD.

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.

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

Hailey-Hailey disease (HHD) is a kind of autosomal dominant dermatosis. The ATP2C1 gene has been identified as the pathogenic gene of HHD since 2000. In this study, direct DNA sequencing was used to identify ATP2C1 gene mutations in four Chinese families and two sporadic cases with HHD. The entire coding and flanking intronic sequences of ATP2C1 were screened for mutations and five heterozygous mutations of the ATP2C1 gene were detected in the four pedigrees and two sporadic cases with HHD. Four of them were novel, including three frame-shift mutations (c.1330delC, c.888_889insT, c.478_479insA) and one nonsense mutation (c.1720C>T). These data added new variants to the database of ATP2C1 mutations associated with HHD.

Mendelian Disorders of Cornification Caused by Defects in Intracellular Calcium Pumps: Mutation Update and Database for Variants in ATP2A2 and ATP2C1 Associated with Darier Disease and Hailey-Hailey Disease

The two disorders of cornification associated with mutations in genes coding for intracellular calcium pumps are Darier disease (DD) and Hailey-Hailey disease (HHD). DD is caused by mutations in the ATP2A2 gene, whereas the ATP2C1 gene is associated with HHD. Both are inherited as autosomal-dominant traits. DD is mainly defined by warty papules in seborrheic and flexural areas, whereas the major symptoms of HHD are vesicles and erosions in flexural skin. Both phenotypes are highly variable. In 12%-40% of DD patients and 12%-55% of HHD patients, no mutations in ATP2A2 or ATP2C1 are found. We provide a comprehensive review of clinical variability in DD and HHD and a review of all reported mutations in ATP2A2 and ATP2C1. Having the entire spectrum of ATP2A2 and ATP2C1 variants allows us to address the question of a genotype-phenotype correlation, which has not been settled unequivocally in DD and HHD. We created a database for all mutations in ATP2A2 and ATP2C1 using the Leiden Open Variation Database (LOVD v3.0), for variants reported in the literature and future inclusions. This data may be of use as a reference tool in further research on treatment of DD and 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.

The genetics of human skin disease

The skin is composed of a variety of cell types expressing specific molecules and possessing different properties that facilitate the complex interactions and intercellular communication essential for maintaining the structural integrity of the skin. Importantly, a single mutation in one of these molecules can disrupt the entire organization and function of these essential networks, leading to cell separation, blistering, and other striking phenotypes observed in inherited skin diseases. Over the past several decades, the genetic basis of many monogenic skin diseases has been elucidated using classical genetic techniques. Importantly, the findings from these studies has shed light onto the many classes of molecules and essential genetic as well as molecular interactions that lend the skin its rigid, yet flexible properties. With the advent of the human genome project, next-generation sequencing techniques, as well as several other recently developed methods, tremendous progress has been made in dissecting the genetic architecture of complex, non-Mendelian skin diseases.

Using yeast to model calcium-related diseases: example of the Hailey-Hailey disease

Cross-complementation studies offer the possibility to overcome limitations imposed by the inherent complexity of multicellular organisms in the study of human diseases, by taking advantage of simpler model organisms like the budding yeast Saccharomyces cerevisiae. This review deals with, (1) the use of S. cerevisiae as a model organism to study human diseases, (2) yeast-based screening systems for the detection of disease modifiers, (3) Hailey-Hailey as an example of a calcium-related disease, and (4) the presentation of a yeast-based model to search for chemical modifiers of Hailey-Hailey disease. The preliminary experimental data presented and discussed here show that it is possible to use yeast as a model system for Hailey-Hailey disease and suggest that in all likelihood, yeast has the potential to reveal candidate drugs for the treatment of this disorder. This article is part of a Special Issue entitled: Calcium signaling in health and disease. Guest Editors: Geert Bultynck, Jacques Haiech, Claus W. Heizmann, Joachim Krebs, and Marc Moreau.

A case of Hailey-Hailey disease in an infant with a new ATP2C1 gene mutation

Familial benign chronic pemphigus or Hailey-Hailey disease (OMIM 169600) is an autosomal-dominant blistering disease. Here we present a rare case of familial benign chronic pemphigus in a Chinese infant. The 5-month-old proband, who showed diffusely distributed skin lesions, is the youngest patient of Hailey-Hailey disease ever reported. The detection of an ATP2C1 gene mutation in this infant confirmed the diagnosis. His mother carried the same mutation, but with no history of skin lesions.

Heterogeneous mutations of the ATP2C1 gene causing Hailey-Hailey disease in Hong Kong Chinese

BACKGROUND

Hailey-Hailey disease (HHD) is a rare autosomal dominant dermatosis. It causes suprabasilar acantholysis leading to vesicular and crusted erosions affecting the flexures. Mutation of ATP2C1 gene encoding the human secretory pathway Ca(2+) /Mn(2+) -ATPase (hSPCA1) was identified to be the cause of this entity.

OBJECTIVE

The aim of this study was to study the mutational profile of the ATP2C1 gene in Hong Kong Chinese patients with HHD.

METHODS

Patients with the clinical diagnosis of HHD proven by skin biopsy were included in this study. Mutation analysis was performed in 17 Hong Kong Chinese patients with HHD.

RESULTS

Ten mutations in the ATP2C1 gene were found. Six of these were novel mutations. The novel mutations included a donor splice site mutation (IVS22+1G>A); a missense mutation (c.1049A>T); two deletion mutations (c.185_188delAGTT and c.923_925delAAG); an acceptor splice site mutation (IVS21-1G>C) and an insertion mutation (c.2454dupT).

CONCLUSION

The six novel mutations provide additions to the HHD mutation database. No hot-spot mutation was found and high allelic heterogeneity was demonstrated in the Hong Kong Chinese patients.

A novel missense mutation of the ATP2C1 gene in a Chinese patient with Hailey-Hailey disease

Benign familial chronic pemphigus (Hailey-Hailey disease, HHD; MIM 169600) is a rare autosomal dominant hereditary disorder characterized by pruritic vesicles, painful erosions and scaly erythematous plaques at the sites of friction and flexures. Mutations in ATP2C1, which encoding the human secretory pathway Ca²(+)/Mn²(+)-ATPase protein 1 (hSPCA1), have been identified as the pathogenic gene of HHD. We found a novel, distinct, heterozygous mutation during study of a Chinese patient with HHD. We identified a C→T transition at nucleotide 1235 (p.Thr352IIe), in exon 13 of ATP2C1. This observation would be useful for genetic counseling and prenatal diagnosis for affected families and in expanding the repertoire of ATP2C1 mutations underlying HHD.

Genetic diagnosis of Hailey-Hailey disease in two Chinese families: novel mutations in the ATP2C1 gene

Hailey-Hailey disease (HHD; OMIM 169600), is an autosomal dominantly inherited disorder characterized by suprabasal cell separation of the epidermis. Mutations in ATP2C1, which encodes the human secretory pathway Ca(2+)/ Mn(2) +/- ATPase protein 1 (hSPCA1), have been identified as the pathogenic gene of HHD without evidence of genetic heterogeneity. In this study, the ATP2C1 gene was screened in two typical Chinese pedigrees with HHD, and two specific novel mutations of the ATP2CL gene were identified. Family 1 had a 16-base deletion mutation c.1068-1083del16 and family 2 had a substitution mutation c.1982T>G (p.Met661Arg). DNA sequencing of the three descendants of the probands revealed that they all had the normal genotype, indicating that there had been no transmission of the mutation.

Calcium Pumps in Health and Disease

Ca2+-ATPases (pumps) are key actors in the regulation of Ca2+ in eukaryotic cells and are thus essential to the correct functioning of the cell machinery. They have high affinity for Ca2+ and can efficiently regulate it down to very low concentration levels. Two of the pumps have been known for decades (the SERCA and PMCA pumps); one (the SPCA pump) has only become known recently. Each pump is the product of a multigene family, the number of isoforms being further increased by alternative splicing of the primary transcripts. The three pumps share the basic features of the catalytic mechanism but differ in a number of properties related to tissue distribution, regulation, and role in the cellular homeostasis of Ca2+. The molecular understanding of the function of the pumps has received great impetus from the solution of the three-dimensional structure of one of them, the SERCA pump. These spectacular advances in the structure and molecular mechanism of the pumps have been accompanied by the emergence and rapid expansion of the topic of pump malfunction, which has paralleled the rapid expansion of knowledge in the topic of Ca2+-signaling dysfunction. Most of the pump defects described so far are genetic: when they are very severe, they produce gross and global disturbances of Ca2+ homeostasis that are incompatible with cell life. However, pump defects may also be of a type that produce subtler, often tissue-specific disturbances that affect individual components of the Ca2+-controlling and/or processing machinery. They do not bring cells to immediate death but seriously compromise their normal functioning.

Molecular and clinical characterization in Japanese and Korean patients with Hailey-Hailey disease: six new mutations in the ATP2C1 gene

BACKGROUND

The autosomal dominant disorder Hailey-Hailey disease (HHD) results from mutations in the ATP2C1 gene, which encodes the human secretory pathway Ca2+/Mn2+ -ATPase protein 1. To date, over 90 pathological mutations scattered throughout ATP2C1 have been described with no indication of mutational hotspots or clustering of mutations. No paradigm for genotype-phenotype correlation has emerged.

OBJECTIVES

To determine the pathogenic ATP2C1 abnormality in additional patients with HHD in order to provide further contributions to the understanding of the molecular basis of this disorder and to add the data to the known mutation database.

METHODS

In this study, we investigated eight unrelated Japanese and Korean patients with HHD. We performed direct nucleotide sequencing of the ATP2C1 gene in all patients and RT-PCR analysis, using RNA extracted from a skin biopsy, in a patient with the mildest clinical features.

RESULTS

We identified seven different heterozygous mutations in seven of the eight investigated patients, including three new single nucleotide deletion/duplication mutations: c.520delC; c.681dupA; c.956delC, three new donor splice site mutations: c.360+1G>C; c.899+1G>T; c.1570+2T>C, as well as a previously described nonsense mutation: p.Arg153X. RT-PCR analysis in the mildest affected patient with a heterozygous c.360+1G>C mutation, demonstrated expression of a short in-frame mutant transcript with exon 5 skipping, which may account for the mild phenotype.

CONCLUSIONS

The results expand the known mutation spectrum in HHD and show the importance of RNA analysis for understanding the genotype-phenotype correlations more precisely.

Genetic diagnosis in a Chinese Hailey-Hailey disease pedigree with novel ATP2C1 gene mutation

Hailey-Hailey disease (HHD) is an autosomal dominant skin disorder characterized by recurrent eruption of vesicles and bullae at the sites of friction and in the intertriginous areas. Mutations in the ATP2C1 gene encoding the human secretory pathway calcium ATPase 1 (hSPCA1) have been identified as the causative mutations in HHD. In this study, we used direct sequencing and restriction endonuclease digestion to analyze mutations of the ATP2C1 gene in a Chinese three-generation pedigree. A heterozygous T-to-C transition at nucleotide 1004 in exon 12 of ATP2C1 gene was detected. After summarizing the reported cases with ATP2C1 mutation, we concluded that the T1004C transition resulted in a novel missense mutation of leucine condon (CTG) to proline (CCG) at amino acid residue 335(L335P) in hSPCA1. Here, a genetic diagnosis was made for the proband's daughter before the clinical presentation. The study realized the molecular diagnosis in the HHD pedigree. Our findings should be useful for genetic counseling and prenatal diagnosis for the affected family and in demonstrating the critical role of the ATP2C1 gene in the pathogenesis of HHD further.

Calcium in the Golgi apparatus

The secretory-pathway Ca2+-ATPases (SPCAs) represent a recently recognized family of phosphorylation-type ATPases that supply the lumen of the Golgi apparatus with Ca2+ and Mn2+ needed for the normal functioning of this structure. Mutations of the human SPCA1 gene (ATP2C1) cause Hailey-Hailey disease, an autosomal dominant skin disorder in which keratinocytes in the suprabasal layer of the epidermis detach. We will first review the physiology of the SPCAs and then discuss how mutated SPCA1 proteins can lead to an epidermal disorder.

SERCA pumps and human diseases

Sarco(endo)plasmic reticulum (SER) Ca2+ ATPases represent a highly conserved family of Ca2+ pumps which actively transport Ca2+ from the cytosol to the SER against a large concentration gradient. In humans, 3 genes (ATP2A1-3) generate multiple isoforms (SERCAla,b, SERCA2a-c, SECA3a-f) by developmental or tissue-specific alternative splicing. These pumps differ by their regulatory and kinetic properties, allowing for optimized function in the tissue where they are expressed. They play a central role in calcium signalling through regenerating SER Ca2+ stores, maintaining appropriate Ca2+ levels in this organelle and shaping cytosolic and nuclear Ca2+ variations which govern cell response. Defects in ATP2A1 encoding SERCA1 cause recessive Brody myopathy, mutations in ATP2A2 coding for SERCA2 underlie a dominant skin disease, Darier disease and its clinical variants. SERCA2a expression is reduced in heart failure in human and in mice models. Gene-targeting studies in mouse confirmed the expected function of these isoforms in some cases, but also resulted in unexpected phenotypes: SERCA1 null mutants die from respiratory failure, SERCA2 heterozygous mutant mice develop skin cancer with age and SERCA3 null mice display no diabetes. These unique phenotypes have provided invaluable information on the role of these pumps in specific tissues and species, and have improved our understanding of Ca2+ regulated processes in muscles, the heart and the skin in human and in mice. Although the understanding of the pathogenesis of these diseases is still incomplete, these recent advances hold the promise of improved knowledge on the disease processes and the identification of new targets for therapeutic interventions.

Diseases involving the Golgi calcium pump

Secretory-pathway Ca2(+)-transport ATPases (SPCA) provide the Golgi apparatus with Ca2+ and Mn2+ needed for the normal functioning of this organelle. Loss of one functional copy of the human SPCA1 gene (ATP2C1) causes Hailey-Hailey disease, a rare skin disorder characterized by recurrent blisters and erosions in the flexural areas. Here, we will review the properties and functional role of the SPCAs. The relationship between Hailey-Hailey disease and its defective gene (ATP2C1) will be adressed as well.

Eight novel mutations of ATP2C1 identified in 17 Chinese families with Hailey-Hailey disease

BACKGROUND

Hailey-Hailey disease (HHD) is a rare autosomal dominantly inherited dermatosis, characterized by persistent blisters and erosions of the skin. It was recently discovered that HHD was caused by mutations in the ATP2C1 gene, a Ca2+ pump located in the Golgi apparatus.

OBSERVATION

In this study, we sequenced the ATP2C1 gene from blood samples of 31 patients in 17 unrelated Chinese families and 120 healthy individuals. Eight novel mutations were identified in 9 families, including 3 insertion/deletions (nt 1464-1487/1462-1485 del, 1523 del AT, 2375 del TTGT), 3 splicing-site mutations [360(-2)a-->g, 1415(-2)a-->c, 2243(+2)t-->c], and 2 missense mutations (P307L, D648Y).

CONCLUSION

Eight mutations were found in 8 unrelated families and 1 sporadic case, and these new findings have further improved our understanding of the role of ATP2C1 in HHD.

Autosomal-dominant calcium ATPase disorders

Darier disease (DD) and Hailey-Hailey disease (HHD) are the only known autosomal-dominant Ca2+ ATPase disorders. Epidermal symptoms selectively occur in the affected individuals, the precise reason for which is still not fully understood. Here, we review the clinical, epidermal, and molecular features of the two genodermatoses. It is concluded that epidermal Ca2+ regulation disturbances and epigenetic factors may play an even more prominent role in the pathogenesis of DD and HHD than earlier appreciated.

Novel mutation in ATP2C1 gene in a Japanese patient with Hailey-Hailey disease

Hailey-Hailey disease (HHD) is an autosomal dominant disorder with recurrent eruption of vesicles and bullae involving predominantly the neck, groin and axillary regions. Histopathology shows suprabasal cleavage in epidermal cells. Recent studies have revealed that HHD is caused by mutations in the ATP2C1 gene encoding a novel Ca(2+) pump. We analyzed mutations of the ATP2C1 gene in 2 Japanese patients with HHD. The diagnosis of HHD was made based on the characteristic clinical features and histopathological evidence. All 27 exons and flanking intron boundaries were amplified by polymerase chain reaction and products analyzed by sequencing. As a result, we identified a novel missense mutation (A1087G) in exon 13 of the ATP2C1 gene in a patient. This mutation led the amino acid change from Thrto Ala in the phosphorylation protein domain. Another patient showed no mutation of the gene. These results demonstrate that a spectrum of ATP2C1 gene mutations is present in Japanese HHD patients.

ATP2C1 Gene Mutation Analysis in Italian Patients with Hailey–Hailey Disease

Hailey-Hailey disease (HHD) is a rare autosomal dominant disorder characterized by recurrent skin lesions predominantly involving the body folds. It is caused by heterozygous mutations in the ATP2C1 gene, encoding the human secretory pathway Ca2+/Mn2+-ATPase protein 1 (hSPCA1). In this report we describe the molecular studies performed in eight HHD cases from Italy that led us to identify six different mutations scattered through the ATP2C1 gene in seven of eight cases. Four of the detected mutations were novel. Our results confirm the high allelic heterogeneity of the ATP2C1 gene and support the notion that HHD is a genetically homogeneous disorder. Furthermore, we created a table summarizing all previously reported ATP2C1 mutations, adapting the nomenclature, if needed, according to the guidelines of the Human Genome Variation Society.

Detection of ATP2C1 gene mutation in familial benign chronic pemphigus

The ATP2C1 gene mutation in one case of familial benign chronic pemphigus was investigated. One patient was diagnosed as familial benign chronic pemphigus by pathology, ultrastructral examination and clinical features. Genomic DNA was extracted from blood samples. Mutation of ATP2C1 gene was detected by polymerase chain reaction (PCR) and DNA sequencing. The results showed that deletion mutation was detected in ATP2C1 gene in this patient, which was 2374delTTTG. No mutation was found in the family members and normal individuals. It was concluded that the 2374delTTTG mutation in ATP2C1 gene was the specific mutation for the clinical phenotype for this patient and was a de novo mutation.

Transcriptional regulation of ATP2C1 gene by Sp1 and YY1 and reduced function of its promoter in Hailey-Hailey disease keratinocytes

Hailey-Hailey disease (HHD) is a blistering skin disease caused by malfunction of the Ca2+-dependent ATPase, ATP2C1. In this study, key regulatory regions necessary for the expression of the gene encoding human ATP2C1 were investigated. The transient reporter assay demonstrated that region +21/+57 was necessary for activation of the ATP2C1 promoter, and the electrophoretic mobility shift assay demonstrated that the region was recognized by the transcription factors, Sp1 and YY1. In accordance with this result, when Sp1 or YY1 was overexpressed in keratinocytes, an obvious increase in ATP2C1 promoter activity was observed, which was in contrast with the case where a mutant promoter lacking the binding sites for Sp1 and YY1 was used as the reporter. Ca2+-stimulation signal increased nuclear Sp1 proteins and ATP2C1 mRNA levels in normal keratinocytes. In contrast, both these increases were suppressed in keratinocytes from HHD patients. These results indicate that Sp1 and YY1 transactivate the human ATP2C1 promoter via cis-enhancing elements and that incomplete upregulation of ATP2C1 transcription contributes to the keratinocyte-specific pathogenesis of HHD. This is a report describing the regulation of the expression of ATP2C1.

Hailey-Hailey disease as an orthodisease of PMR1 deficiency in Saccharomyces cerevisiae

The term orthodisease has recently been introduced to define human disorders in which the pathogenic gene has orthologs in model organism genomes. Here, we describe Hailey-Hailey disease (HHD), a blistering skin disorder caused by haploinsufficiency of ATP2C1 as an orthodisease from a Saccharomyces cerevisiae perspective. ATP2C1 encodes the human secretory pathway Ca(2+)/Mn(2+) ATPase hSPCA1 and is orthologous to the PMR1 gene in S. cerevisiae. hSPCA1 fully complements PMR1 deficiency in yeast and pmr1DeltaS. cerevisiae has proved to be a valuable tool to screen ATP2C1 mutations and address potential pathogenic/pharmacologic mechanisms in HHD. Consequently, this human skin disorder is an ideal example of an orthodisease.

Effects of drugs and anticytokine antibodies on expression of ATP2A2 and ATP2C1 in cultured normal human keratinocytes

BACKGROUND

Darier's disease (DD) and Hailey-Hailey disease (HHD) are skin disorders arising, respectively, from autosomal dominant mutations in ATP2A2, encoding the sacro/endoplasmic reticulum calcium ATPase, and ATP2C1, encoding the Golgi apparatus calcium ATPase. Exposure to ultraviolet (UV) B irradiation exacerbates the skin lesions, which can be treated with corticosteroids and retinoids.

OBJECTIVES

To investigate the molecular basis for DD and HHD.

METHODS

We used quantitative reverse transcriptase-polymerase chain reactions to examine the effects of UVB irradiation on ATP2A2 and ATP2C1 mRNA levels in cultured normal keratinocytes.

RESULTS

We observed that UVB irradiation reduced ATP2A2 and ATP2C mRNA levels. The addition of retinoids or corticosteroids to the cell culture inhibited the UVB-induced suppression of both ATP2A2 and ATP2C1 mRNA levels, and UVB-induced suppression of ATP2C1 mRNA was also inhibited by the addition of ciclosporin, tacrolimus and vitamin D(3). The addition of anti-interleukin (IL)-6 antibody to the cell culture prevented the UVB-induced suppression of ATP2A2 and ATP2C1 mRNA; in contrast, the addition of anti-IL-8 antibody slightly accelerated the suppression.

CONCLUSIONS

These results suggest that drugs effective for DD and HHD act by modulating ATP2A2 and ATP2C1 mRNA expression, respectively, and that the proinflammatory cytokines IL-6 and IL-8 play important roles in the regulation of ATPA2 and ATP2C1 expression in homeostasis and/or inflammation of the skin.

Calcium pump disorders of the skin

The causes of Darier disease (DD) and Hailey-Hailey disease (HHD) have eluded clinicians and scientists for more than 60 years. DD is characterized by loss of adhesion between suprabasal epidermal cells associated with abnormal keratinization, while loss of epidermal cell-to-cell adhesion is predominant in HHD. The genes for both conditions have recently been identified using candidate positional cloning approaches. The gene for DD (ATP2A2) encodes a calcium transport ATPase of the sarco (endo)plasmic reticulum (SERCA2) Verboomen et al. [1992: Biochem J 286(Pt 2):591-595], while the gene for HHD (ATP2C1) codes for a secretory pathway for calcium and manganese transport ATPase of the Golgi apparatus (SPCA1) Hu et al. [2000: Nat Genet 24:61-65]. These results have provided completely new insights into the role of calcium and/or manganese in maintaining skin integrity. Although the precise disease mechanisms remain to be understood, these discoveries open a new field in research for the understanding and the treatment of these distressing disorders.

The Ca2+/Mn2+ pumps in the Golgi apparatus

Recent evidence highlights the functional importance of the Golgi apparatus as an agonist-sensitive intracellular Ca(2+) store. Besides Ca(2+)-release channels and Ca(2+)-binding proteins, the Golgi complex contains Ca(2+)-uptake mechanisms consisting of the well-known sarco/endoplasmic reticulum Ca(2+)-transport ATPases (SERCA) and the much less characterized secretory-pathway Ca(2+)-transport ATPases (SPCA). SPCA supplies the Golgi compartments and, possibly, the more distal compartments of the secretory pathway with both Ca(2+) and Mn(2+) and, therefore, plays an important role in the cytosolic and intra-Golgi Ca(2+) and Mn(2+) homeostasis. Mutations in the human gene encoding the SPCA1 pump (ATP2C1) resulting in Hailey-Hailey disease, an autosomal dominant skin disorder, are discussed.

SPCA1 pumps and Hailey-Hailey disease

Both the endoplasmic reticulum and the Golgi apparatus are agonist-sensitive intracellular Ca2+ stores. The Golgi apparatus has Ca2+-release channels and a Ca2+-uptake mechanism consisting of sarco(endo)plasmic-reticulum Ca2+-ATPases (SERCA) and secretory-pathway Ca2+-ATPases (SPCA). SPCA1 has been shown to transport both Ca2+ and Mn2+ in the Golgi lumen and therefore plays an important role in the cytosolic and intra-Golgi Ca2+ and Mn2+ homeostasis. Human genetic studies have provided new information on the physiological role of SPCA1. Loss of one functional copy of the SPCA1 (ATP2C1) gene causes Hailey-Hailey disease, a skin disorder arising in the adult age with recurrent vesicles and erosions in the flexural areas. Here, we review recent experimental evidence showing that the Golgi apparatus plays a much more important role in intracellular ion homeostasis than previously anticipated.

Darier’s disease: from dyskeratosis to endoplasmic reticulum calcium ATPase deficiency

The skin is the body's largest organ and has an essential barrier protective function against physical, chemical, and pathogen aggressions and prevents fluid loss. The outer layer of the skin, known as the epidermis, plays a key role in this protection, through a tightly regulated differentiation programme from basal keratinocytes to the stratum corneum at the skin surface. During this process, keratinocytes from the base of the epidermis undergo major morphological and functional changes during their migration through the spinous and granular layers, to become terminally differentiated corneocytes which will be shed from the skin's surface. The role of extracellular Ca2+ in cell-to-cell adhesion and in epidermal differentiation was known to be important, but the identification of the sarco/endoplasmic reticulum Ca2+ transport ATPase (ATP2A2) as the defective gene in a rare genetic skin disease known as Darier's disease, came as a surprise and shed light on the key role of Ca2+ signaling in the homeostasis of the epidermis.

Hailey–Hailey Disease: Identification of Novel Mutations in ATP2C1 and Effect of Missense Mutation A528P on Protein Expression Levels

ATP2C1, encoding the human secretory pathway Ca(2+)-ATPase (hSPCA1), was recently identified as the defective gene in Hailey-Hailey disease (HHD), an autosomal dominant skin disorder characterized by abnormal keratinocyte adhesion in the suprabasal layers of the epidermis. In this study, we used denaturing high-performance liquid chromatography to screen all 28 exons and flanking intron boundaries of ATP2C1 for mutations in 9 HHD patients. Nine different mutations were identified. Five of these mutations, including one nonsense, one deletion, two splice-site, and one missense mutation, have not been previously reported. Recently, functional analysis of a series of site-specific mutants, designed to mimic missense mutations found in ATP2C1, uncovered specific defects in Ca(2+) and/or Mn(2+) transport and protein expression in mutant hSPCA1 polypeptides. In order to investigate the molecular and physiological basis of HHD in the patient carrying missense mutation A528P, located in the putative nucleotide binding domain of the molecule, site-directed mutagenesis was employed to introduce this mutation into the wild-type ATP2C1 (hSPCA1) sequence. Functional analyses of HHD-mutant A528P demonstrated a low level of protein expression, despite normal levels of mRNA and correct targeting to the Golgi, suggesting instability or abnormal folding of the mutated hSPCA1 polypeptides. Analogous to conclusions drawn from our previous studies, these results further support the theory of haploinsufficiency as a prevalent mechanism for the dominant inheritance of HHD, by suggesting that the level of hSPCA1 in epidermal cells is critical.

Calcium pumps and keratinocytes: lessons from Darier's disease and Hailey-Hailey disease

Darier's disease and Hailey-Hailey disease are autosomal dominantly inherited skin disorders in which desmosomal adhesion between keratinocytes is abnormal. ATP2A2 and ATP2C1 have been identified as the causative genes for Darier's disease and Hailey-Hailey disease, respectively. ATP2A2 encodes the sarco(endo)plasmic reticulum Ca(2+)-ATPase isoform 2 (SERCA2) pump, while ATP2C1 encodes a secretory pathway Ca(2+)/Mn(2+)-ATPase (SPCA1) found in the Golgi apparatus. We review recent work into the function of these pumps in human keratinocytes and discuss how mutations in these genes might cause these diseases by altering the formation or stability of desmosomes.

Four novel mutations in ATP2C1 found in Chinese patients with Hailey-Hailey disease

BACKGROUND

Familial benign chronic pemphigus or Hailey-Hailey disease (HHD; OMIM 169600) is an autosomal dominant blistering disease. Pathogenic mutations in ATP2C1 encoding a novel Ca2+ pump have recently been identified.

OBJECTIVES

To identify mutations in ATP2C1 in Chinese patients with HHD.

METHODS

Eleven unrelated Chinese patients with HHD were subjected to mutation detection in ATP2C1. Eight of them had a family history of HHD. The 27 coding exons and their flanking sequences were amplified and sequenced.

RESULTS

Five of the 11 patients were identified to have heterozygous mutations including three nonsense mutations and two splicing mutations in ATP2C1.

CONCLUSIONS

Four novel mutations, nonsense mutations S887X and W795X and splicing mutations 118-1 g-->a and 1890+1del(gtgag)ins53, were found in this series of Chinese patients with HHD.

[Disseminated M. Hailey-Hailey]

Along with the typical intertriginous localization of Hailey-Hailey disease, generalized cutaneous involvement may also occur. Besides nonspecific triggers, genetic factors are considered to be responsible. Mutations of the ATP2C1 gene have been identified as causative factors in this genetic disease. No direct genotype-phenotype correlation between a specific mutation and the disseminated variant of Hailey-Hailey disease has been demonstrated.

Molecular physiology of the SERCA and SPCA pumps

Intracellular Ca(2+)-transport ATPases exert a pivotal role in the endoplasmic reticulum and in the compartments of the cellular secretory pathway by maintaining a sufficiently high lumenal Ca(2+) (and Mn(2+)) concentration in these compartments required for an impressive number of vastly different cell functions. At the same time this lumenal Ca(2+) represents a store of releasable activator Ca(2+) controlling an equally impressive number of cytosolic functions. This review mainly focuses on the different Ca(2+)-transport ATPases found in the intracellular compartments of mainly animal non-muscle cells: the sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) pumps. Although it is not our intention to treat the ATPases of the specialized sarcoplasmic reticulum in depth, we can hardly ignore the SERCA1 pump of fast-twitch skeletal muscle since its structure and function is by far the best understood and it can serve as a guide to understand the other members of the family. In a second part of this review we describe the relatively novel family of secretory pathway Ca(2+)/Mn(2+) ATPases (SPCA), which in eukaryotic cells are primarily found in the Golgi compartment.