Hailey-Hailey Disease Patients Research Articles

Patients' perspective, quality of life and treatment goals in Hailey-Hailey disease: Lessons learned from the German National Registry.

Hailey-Hailey disease (HHD) remains a difficult-to-treat dermatosis and little is known about the patient's perception of the disease activity, the treatment success and its impact on quality-of-life (QoL). To obtain better understanding of HHD patients' needs regarding their medical condition, financial burden, QoL, subjective well-being and treatment thereof as well as satisfaction to evaluate common treatments' 'real-life' relevance. With initiation of the national registry for Darier's disease (DD; Morbus Darier, MD) and Hailey-Hailey disease (HH) MDHHgermany, patients with HHD diagnosis were included starting June 2020. To assess subjective symptoms, patients filled out questionnaires such as the DLQI (dermatological life quality index), numeric rating scale (NRS) for itch, pain and burning sensation, as well as the SWLS (satisfaction with life scale) questionnaire to quantify overall satisfaction in life. Additionally, data on therapies were collected along with the patients' satisfaction of those and their medical care. Furthermore, patients assessed financial aspects and work ability. One hundred and two patients were recruited from dermatology clinics, office-based dermatologists and self-help platforms across Germany between June 2020 and February 2023, 90 were eligible and analysed (mean: 49.91 years, 73.33% females, 26.67% males). 39.77% stated according to the DLQI their life is severely/very severely affected. Satisfaction with life was mediocre. Burning sensation was most pronounced among subjective symptoms (NRS 5.85 ± 2.80). Systemic treatments were rated as ineffective according to 56.92%, 25.56% had never received one. Most prescribed systemic treatments were corticosteroids (73.8%), followed by low-dose naltrexone (LDN) (26.2%), retinoids (15.4%) and antibiotics (13.8%). Satisfaction with medical care was generally low. Our 'real-life' data state a major disease burden and impact on the QoL for affected individuals, as well as limited disease control due to inadequate therapies. MDHHgermany can provide insights into improvement of healthcare support with this debilitating disease and improve QoL. In the long term, it aims to provide basis for further clinical trials, epidemiological studies and immunological investigations.

Double-Blind, Placebo-Controlled Study of Onabotulinumtoxin A for the Treatment of Hailey-Hailey Disease.

Hailey-Hailey disease (HHD) can be treated with topical steroids, antibiotics, and invasive surgical procedures. Since sweating often exacerbates HHD lesions, the use of onabotulinumtoxin A could serve as an adjunctive treatment. The goal of this study was to evaluate the safety and efficacy of onabotulinumtoxin A for the treatment of HHD. A double-blind, placebo-controlled single center study was conducted. Six HHD patients who successfully completed this trial in addition to 1 patient who exited early are reported and discussed. Four of these patients received an initial injection of Btx-A and 3 received the placebo initially. All patients except 1 who received an initial or reinjection of Btx-A decreased 2 levels on a 4-point clinical severity scale at weeks 8 or 12 after treatment. Patient 6 received an initial placebo injection and maintained clearance for 6 months, while patients 5 and 7 did not have any improvement in their target lesions after a placebo injection. All patients who received a reinjection of Btx-A at the week 4 follow-up decreased by at least 1 level on the HHD severity scale. Btx-A is a safe treatment that is effective for most cases of HHD. The most severe cases of HHD may not respond to Btx-A as sole treatment. J Drugs Dermatol. 2023;22(4): doi:10.36849/JDD.6857 Citation: Saal R, Oldfield C, Bota J, et al. Double-blind, placebo-controlled study of Onabotulinumtoxin A for the treatment of Hailey-Hailey disease. J Drugs Dermatol. 2023;22(4):339-343. doi:10.36849/JDD.6857.

The Pathogenic Mechanism of the ATP2C1 p.Ala109_Gln120del Mutation in Hailey-Hailey Disease.

BackgroundHailey–Hailey disease (HHD) is an autosomal dominant cutaneous disorder that manifests as repeated blisters and erosions on flexural or intertriginous skin areas. The calcium-transporting ATPase type 2C member 1 gene (ATP2C1) encodes the secretory pathway Ca2+/Mn2+-ATPase 1 (SPCA1), whose deficiency is responsible for HHD. An ATP2C1 splice-site mutation (c.325-2A>G, p.Ala109_Gln120del) was previously identified in a Han Chinese family with HHD.MethodsIn this study, the identified ATP2C1 splice-site mutation (c.325-2A>G, p.Ala109_Gln120del) was investigated in transfected human embryonic kidney 293 cells to analyze its pathogenic mechanism in HHD patients by using cycloheximide chase assay, CCK8 assay and in silico modeling of SPCA1 mutant.ResultsCycloheximide chase assay showed that the degradation rate of the SPCA1 mutant was not obviously faster than that of the normal SPCA1. CCK8 assay showed that cell proliferation rates in the wild-type, A109_Q120del, and empty vector control groups all decreased in the gradient Mn2+ solutions in a dose-dependent manner. The cell proliferation rate in the wild-type was lower than that in the A109_Q120del and empty vector control (both P < 0.01), indicating overexpression of normal SPCA1 may rather induce Golgi stress, and even cell death. The cell proliferation rate in the A109_Q120del was lower than that in the empty vector control (P < 0.01), indicating that overexpression of the mutated SPCA1 may decrease its detoxification capability. Three-dimensional (3D) structure model of SPCA1 built by SWISS-MODEL and PyMOL showed that absence of the 12 amino acids from p.Ala109 to p.Gln120 in the SPCA1 mutant can cause obviously shortened transmembrane 2, which may affect correct localization of SPCA1 on the Golgi.ConclusionThese results demonstrate that the ATP2C1 mutation (c.325-2A>G, p.Ala109_Gln120del) may cause impaired SPCA1 capability to detoxify Mn2+ and abnormal SPCA1 structure, which reveals a new side for the pathogenesis of HHD.

090 Darier disease patients exhibit cognitive impairment while Hailey-Hailey disease patients do not: an experimental, matched case-control study

Darier disease and Hailey-Hailey disease are severe, monogenetic dermatological disorders with mutations affecting all cells, making them liable to exhibit extra-dermal symptoms. The purpose of this study is to assess broad cognitive function in individuals with both diseases using an experimental, case-control setup comparing cognition in patients compared with healthy controls matched for age, sex and level of education. Cognition was assessed with the Cambridge Neuropsychological Test Automated Battery.

Whole exome sequencing improves mutation detection in Hailey-Hailey disease.

Hailey-Hailey disease (HHD) is an autosomal dominant monogenic disease that is defective in the ATP2C1 gene. In previous studies, Sanger sequencing was the main method applied to detect mutations in HHD patients, and no mutations in the ATP2C1 gene were found in 12-55% of those reported. The aim of our study was to carry out whole exome sequencing (WES) for the HHD patients in whom efforts to identify mutations by Sanger sequencing had failed, and to find a new pathogenic gene. WES was performed using genomic DNA from 13 HHD patients and 364 in-house healthy controls. Potential pathogenic mutations were subsequently validated by Sanger sequencing. As a result, eight mutations in the ATP2C1 gene were identified using WES. In the remaining five patients, we found one mutation in the ATP2A2 gene which was the causal gene of Darier's disease. Four patients had no detectable mutations in ATP2C1 and the other ATPase genes. Together with our previous study in 2019, the total mutation rate was calculated to be 47/52 (90.4%). These findings demonstrate that WES is capable of improving the mutation detection sensitivity in HHD compared with Sanger sequencing.

Hailey Hailey-a blooming disease

&lt;p&gt;Hailey Hailey disease (HHD) is a rare genetic disorder which is more common in summers. It involves intertriginous areas of the body. Axilla, abdomen, back, nape of neck are the common sites involved. We hereby present three patients of HHD from same geographical area with no blood relation. Two of them had other family members also involved with the similar complaints. One of the patients is 50 years of age. Diagnosis was done both by clinical and histopathological examination. It showed epidermis with intraepidermal bulla and acantholytic keratinocytes giving dilapidated brick wall appearance. Treatment mainly used was topical steroids &amp;amp;antihistamines and patients responded well.&lt;/p&gt;

Identification of ATP2C1 mutations in the patients of Hailey-Hailey disease

BackgroundFamilial benign chronic pemphigus, also known as Hailey-Hailey disease (HHD), is a clinically rare bullous Dermatosis. However the mechanism has not been clarified. The study aim to detect novel mutations in exons of ATP2C1 gene in HHD patients; to explore the possible mechnism of HHD pathogenesis by examining the expression profile of hSPCA1, miR-203, p63, Notch1 and HKII proteins in the skin lesions of HHD patients.MethodsGenomic DNA was extracted from peripheral blood of HHD patients. All exons of ATP2C1 gene in HHD patients were amplified by PCR and the products were purified and sequenced. All related signaling proteins of interest were stained by using skin lesion tissues from HHD patients and miR-203 levels were also determined.ResultsOne synonymous mutation c.G2598A (in exon 26), one nonsense mutation c.C635A and two missense mutations c.C1286A (p.A429D) and c. A1931G (p. D644G) were identified. The nonsense mutation changed codon UCG to stop codon UAG, causing a premature polypeptide chain of the functional region A. The two missense mutations were located in the region P (phosphorylation region) and the Mn binding site of hSPCA1. The level of hSPCA1 was significantly decreased in HHD patients compared to the normal human controls, accompanied by an increase of miR-203 level and a decrease of p63 and HKII levels.ConclusionIn our study, we found four mutations in HHD. Meanwhile we found increase of miR-203 level and a decrease of p63 and HKII levels. In addition, Notch1, which was negatively regulated p63, is downregulated. These factors may be involved in the signaling pathways of HHD pathogenesis. Our data showed that both p63 and miR-203 may have significant regulatory effects on Notch1 in the skin.

SPCA1 governs the stability of TMEM165 in Hailey-Hailey disease

TMEM165 is a Golgi protein whose deficiency causes a Congenital Disorder of Glycosylation (CDG). We have demonstrated that Mn2+ supplementation could suppress the glycosylation defects observed in TMEM165-deficient cells and that TMEM165 was a Mn2+-sensitive protein. In the Golgi, the other transmembrane protein capable to regulate Mn2+/Ca2+ homeostasis is SPCA1, encoded by the ATP2C1 gene. A loss of one copy of the ATP2C1 gene leads to Hailey-Hailey Disease (HHD), an acantholytic skin disorder in Humans. Our latest results suggest an unexpected functional link between SPCA1 and TMEM165. In order to clarify this link in case of partial SPCA1 deficiency, HHD fibroblasts were used to assess TMEM165 expression, subcellular localization and Mn2+-induced degradation. No differences were observed regarding TMEM165 expression and localization in HHD patients’ fibroblasts compared to control fibroblasts. Nevertheless, we demonstrated both for fibroblasts and keratinocytes that TMEM165 expression is more sensitive to MnCl2 exposure in HHD cells than in control cells. We linked, using ICP-MS and GPP130 as a Golgi Mn2+ sensor, this higher Mn2+-induced sensitivity to a cytosolic Mn accumulation in MnCl2 supplemented HHD fibroblasts. Altogether, these results link the function of SPCA1 to the stability of TMEM165 in a pathological context of Hailey-Hailey disease.

Novel and recurrent variants of ATP2C1 identified in patients with Hailey-Hailey disease

Hailey-Hailey disease (HHD) is a rare, late-onset autosomal dominant genodermatosis characterized by blisters, vesicular lesions, crusted erosions, and erythematous scaly plaques predominantly in intertriginous regions. HHD is caused by ATP2C1 mutations. About 180 distinct mutations have been identified so far; however, data of only few cases from Central Europe are available. The aim was to analyze the ATP2C1 gene in a cohort of Polish HHD patients. A group of 18 patients was enrolled in the study based on specific clinical symptoms. Mutations were detected using Sanger or next generation sequencing. In silico analysis was performed by prediction algorisms and dynamic structural modeling. In two cases, mRNA analysis was performed to confirm aberrant splicing. We detected 13 different mutations, including 8 novel, 2 recurrent (p.Gly850Ter and c.325-3 T > G), and 6 sporadic (c.423-1G > T, c.899 + 1G > A, p.Leu539Pro, p.Thr808TyrfsTer16, p.Gln855Arg and a complex allele: c.[1610C > G;1741 + 3A > G]). In silico analysis shows that all novel missense variants are pathogenic or likely pathogenic. We confirmed pathogenic status for two novel variants c.325-3 T > G and c.[1610C > G;1741 + 3A > G] by mRNA analysis. Our results broaden the knowledge about genetic heterogeneity in Central European patients with ATP2C1 mutations and also give further evidence that careful and multifactorial evaluation of variant pathogenicity status is essential.

Identification of 2 Novel Mutations in ATP2C1 Gene in Hailey-Hailey Disease and a Literature Review of Variations in a Chinese Han Population.

BackgroundHailey-Hailey disease (HHD) is a rare autosomal dominant skin condition. The ATP2C1 gene was identified as the defective gene in HHD. To date, 166 pathogenic mutations in ATP2C1 have been observed worldwide. The aim of this study was to identify variations in HHD and summarize the features of the mutations identified in China.Material/MethodsWe examined 2 familial and 2 sporadic cases of HHD. Genomic DNA polymerase chain reaction and direct sequencing of the ATP2C1 were performed from HHD patients, unaffected family members, and 200 healthy individuals. We also searched the published literature for data about the ATP2C1 gene using PubMed and the Chinese Biological Medicine Database.ResultsWe detected 3 heterozygous mutations, including 2 novel frameshift mutations (c.819insA (273LfsX) and c.1264insTAGATGG (421LfsX)) and 1 recurrent nonsense mutation (c.115C>T (R39X)). To the best of our knowledge, 90 different mutations (including our current results) have been reported in China, all of which occurred in the Chinese Han population.ConclusionsOur data may add to the existing list of ATP2C1 mutations and provide new insight into genetic variants of HHD in China.

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.

Carbon dioxide laser treatment for Hailey-Hailey disease: a retrospective chart review with patient-reported outcomes.

Hailey-Hailey disease (HHD) is an autosomal dominant genodermatosis that leads to skin breakdown and blister formation, usually in intertriginous areas. Laser ablation is a known surgical treatment for HHD. We report outcomes in a series of patients with HHD treated with carbon dioxide (CO2 ) laser ablation. A retrospective chart review of data for 13 patients who underwent CO2 laser ablation for HHD was conducted. Questionnaires assessing effectiveness, pain, healing time, recurrence, new disease, complications, additional ablation, improvement in quality of life (QoL), and overall satisfaction were completed by all patients. All patients had been recalcitrant to previous treatments prior to CO2 laser ablation. Anatomic sites treated and anesthesia techniques for the procedure varied. The mean ± standard deviation (SD) score for the effectiveness of CO2 laser ablation for HHD was 9.3 ± 0.9 (maximum: 10). All patients reported improved QoL. No patient had recurring disease within the treatment field. Five patients underwent additional CO2 laser treatments at new sites. One patient reported postoperative infection. No other complications were identified. The mean ± SD score for overall satisfaction with CO2 laser ablation was 8.9 ± 1.1. Treatment with CO2 laser ablation is very effective and can lead to prolonged or permanent remission in most HHD patients. Patients are highly satisfied with the results and report a substantial improvement in QoL.

Mutation‐dependent effects on mRNA and protein expressions in cultured keratinocytes of Hailey–Hailey disease

Hailey-Hailey disease (HHD) is a dominantly inherited skin disease caused by mutations in ATP2C1 gene, which encodes secretory pathway Ca(2+) /Mn(2+) -ATPase protein 1. The precise mechanism remains unclear. In this study, to understand molecular basis of HHD, we examined expression of mRNA and protein in cultured keratinocytes derived from three HHD patients with different mutations. We showed that reduced expression of mRNA and protein in patient with p.Gln504X, but not in patients with p.Pro307His and c.1308+1G>A. RT-PCR analysis for patient with c.1308+1G>A revealed in-frame exon skipping. Reduction of mRNA and protein in p.Gln504X was considered to be caused by nonsense-mediated mRNA decay. p.Pro307His located adjacent to Ca(2+) -binding residue may induced conformational change, which leads to defective Ca(2+) transport. In-frame shorter transcript caused by c.1308+1G>A may have slightly reduced activity, which accounted for mild phenotype of the patient. These results clarified the pathogenic effects of different causative mutations in development of skin lesions.

Detection and comparison of two types of ATP2C1 gene mutations in Chinese patients with Hailey–Hailey disease

The gene ATP2C1 is identified as the defective gene in Hailey-Hailey disease (HHD). The nonsense and missense are two common types of mutations and have, respectively, been detected in many HHD patients. The aims of our study were to identify the pathogenic ATP2C1 abnormality in Chinese HHD patients, and to compare nonsense and missense mutations in vivo to provide further understanding of the molecular and the physiological basis of HHD. The nucleotide sequencing of the ATP2C1 gene was performed in HHD patients, unaffected family members and 100 unrelated individuals. Meanwhile, we detected and analyzed the clinical manifestations, the expression of ATP2C1 mRNA and hSPCA1 protein in the two types of mutations. Three heterozygous mutations were identified, including a previously reported nonsense mutation (R799X), two novel missense mutations (D644G) and (R417K). The results of comparisons between two types of mutations showed that the common clinical features, the similarly low-level expressions of ATP2C1 mRNA and hSPCA1 protein, but the ATP2C1 mRNA expression of nonsense mutation was lower than missense mutation and even less than half the level of normal people. Our findings expand the known spectrum of ATP2C1 mutations in HHD. We supported the haploinsufficiency theory as prevalent mechanism in both types of mutations, and believed that the differences of ATP2C1 mRNA expressions in peripheral blood may relate with the type of mutation and reflect the state of illness of patients.

Mutation analysis of the ATP2C1 gene in Taiwanese patients with Hailey-Hailey disease

Hailey-Hailey disease (HHD) is an autosomal dominant disorder with recurrent pruritic vesicles and erosions, and scaly erythematous plaques, particularly involving intertriginous areas such as the neck, axillae, groins and perineum. Histopathology shows intraepidermal vesiculation with acantholysis in the suprabasal layer. It is caused by heterozygous mutations in the ATP2C1 gene, which encodes for the human secretory pathway Ca 2+ /Mn 2+ ATPase 1. In this study, we analyze the mutations of the ATP2C1 gene in 26 Taiwanese patients with HHD. In total, 21 familial cases from seven families and 5 sporadic cases (including 7 previously reported) were retrieved from the medical records. 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 the products were analyzed by direct sequencing. We identified three nonsense mutations (R39X, R468X, R783X), two splice-site mutations (483 + 2t→a, 832G→A), four deletion mutations (nt884-904del, 1459delCTCA, 1874delA, 1975delA) and one missense mutation (A730T). Two unrelated families with nonsense mutation R783X had the comorbidity of chronic schizophrenia since the third decade. We report two novel mutations (832G→A and 1874delA) of ATP2C1 involved in HHD. The nonsense mutation R783X might represent a mutational “hotspot” in the ATP2C1 gene. The present study demonstrates that a spectrum of ATP2C1 gene mutations is present in Taiwanese HHD patients.

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.

Treatment of Hailey-Hailey disease with topical calcitriol

Calcitriol, 1α25-dihydroxyvitamin D3, can induce differentiation of epidermal keratinocytes into squamous and denucleated horny cells by regulating inter- and intra-cellular calcium concentration.1 Cytoplasmic calcium homeostasis is known to be impaired in keratinocytes from Hailey-Hailey disease (HHD) and the normal epidermal calcium gradient is attenuated in HHD patients.2 These observations and our previous study on the efficacy of systemic calcitriol in HHD,3 led us to use a topical formulation of this compound in an HHD patient.

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.

Effect of Hailey-Hailey Disease Mutations on the Function of a New Variant of Human Secretory Pathway Ca2+/Mn2+-ATPase (hSPCA1)

ATP2C1, encoding the human secretory pathway Ca2+/Mn2+ ATPase (hSPCA1), was recently identified as the defective gene in Hailey-Hailey Disease (HHD), an autosomal dominant skin disorder characterized by persistent blisters and erosions. To investigate the underlying cause of HHD, we have analyzed the changes in expression level and function of hSPCA1 caused by mutations found in HHD patients. Mutations were introduced into hSPCA1d, a novel splice variant expressed in keratinocytes, described here for the first time. Encoded by the full-length of optional exons 27 and 28, hSPCA1d was longer than previously identified splice variants. The protein competitively transported Ca2+ and Mn2+ with equally high affinity into the Golgi of COS-1 cells. Ca2+- and Mn2+-dependent phosphoenzyme intermediate formation in forward (ATP-fuelled) and reverse (Pi-fuelled) directions was also demonstrated. HHD mutant proteins L341P, C344Y, C411R, T570I, and G789R showed low levels of expression, despite normal levels of mRNA and correct targeting to the Golgi, suggesting instability or abnormal folding of the mutated hSPCA1 polypeptides. P201L had little effect on the enzymatic cycle, whereas I580V caused a block in the E1 approximately P --> E2-P conformational transition. D742Y and G309C were devoid of Ca2+- and Mn2+-dependent phosphoenzyme formation from ATP. The capacity to phosphorylate from Pi was retained in these mutants but with a loss of sensitivity to both Ca2+ and Mn2+ in D742Y and a preferential loss of sensitivity to Mn2+ in G309C. These results highlight the crucial role played by Asp-742 in the architecture of the hSPCA1 ion-binding site and reveal a role for Gly-309 in Mn2+ transport selectivity.

Mutation analysis of ATP2C1 gene in Taiwanese patients 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 Ca2+ pump. To analyse the mutations of the ATP2C1 gene in Taiwanese patients with HHD. In total, five familial and two sporadic cases of HHD were retrieved from the medical records. 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 analysed by direct sequencing. We identified six novel mutations and one reported mutation: three deletion mutations (nt884-904del, 1459delCTCA, 1975delA), two non-sense mutations (R39X, R783X), one mis-sense mutation (A730T) and one splicing mutation (483 + 2T-->A). The non-sense mutation R39X had been reported previously; the other six mutations are novel mutations. These results demonstrate that a spectrum of ATP2C1 gene mutations is present in Taiwanese HHD patients.