A Novel R799X Mutation of ATP2C1 Gene in a Chinese Family with Hailey-Hailey Disease

Abstract

Background

Hailey–Hailey disease (HHD) is an autosomal dominantly inherited blistering dermatosis caused by mutations in the ATP2C1 gene, which encodes the human secretory pathway Ca²⁺/Mn²⁺ ATPase protein (hSPCA1).

Methods

We collected a four-generation Chinese HHD family with 6 affected patients. Genomic DNA was isolated from family members and a matched control cohort. All 27 exons and flanking intronic sequences of the ATP2C1 gene were amplified by PCR and subjected to direct sequencing.

Results

A novel heterozygous nonsense mutation, c.2395C>T (p.R799X), was identified in exon 25 of the ATP2C1 gene. This mutation co-segregated with the disease phenotype in the family and was absent in 100 unrelated healthy controls.

Conclusion

This finding expands the mutation spectrum of ATP2C1 underlying HHD and provides a molecular basis for genetic counseling and early diagnosis of at-risk family members.

Introduction

Hailey-Hailey disease (HHD, OMIM^# 16960), also known as familial benign chronic pemphigus, is a rare autosomal dominant genodermatosis characterized by recurrent blisters and erosions in intertriginous areas. It was first described by the Hailey brothers in 1939.¹ Onset typically occurs between the second and fourth decades,² and is characterized by epidermal acantholysis.³ These lesions commonly involve in the neck and intertriginous areas, and rarely affect the mouth,^4,5 esophagus,^6,7 vulva and vagin.^8–10 Asymptomatic longitudinal white bands were present in the fingernails in most patients.¹¹ Environmental factors, such as sweating, friction, and cutaneous infection, usually induce or exacerbate the disease.^8,11 Histopathologically, HHD is defined by widespread suprabasal keratinocyte acantholysis with a “dilapidated brick wall” appearance.¹²

HHD is caused by heterozygous mutations in the ATP2C1 gene (chromosome 3q21–q24), which encodes hSPCA1, a Golgi-resident Ca²⁺/Mn²⁺ ATPase.¹³ hSPCA1 maintains intracellular calcium homeostasis by pumping Ca²⁺ into the Golgi apparatus; its dysfunction disrupts keratinocyte adhesion, leading to acantholysis. To date, over 100 pathogenic ATP2C1 mutations have been reported, including missense, nonsense, frameshift, and splice-site variants, with no obvious mutation hotspots.

Although the genetic basis of HHD is well established, the identification of novel mutations in different ethnic populations remains valuable for expanding the mutation spectrum, refining genotype–phenotype correlations, and improving molecular diagnosis and genetic counseling. However, the current literature lacks data on novel ATP2C1 mutations in Chinese HHD families. In this study, we aimed to identify the pathogenic mutation in a four-generation Chinese family with HHD and expand the mutational spectrum of ATP2C1.

Materials and Methods

Patients and Controls

A four-generation Chinese Han family with HHD (6 affected members) was diagnosed at the Department of Dermatology, Shenzhen Hospital of Southern Medical University. Diagnosis was independently confirmed by two experienced dermatologists based on clinical manifestations and histopathological findings. The study was approved by the Subject Review Board of Shenzhen Hospital of Southern Medical University (Ref# NYSZYYYEC2025K056R002) and conducted in accordance with the Declaration of Helsinki. Written informed consent was obtained from all participants, and consent for publication of clinical images was acquired from the proband.

Peripheral blood samples were collected from 12 available family members (6 affected, 6 unaffected) and 100 unrelated, age- and gender-matched healthy Chinese controls. Controls were recruited from the same geographic region and had no personal or family history of blistering dermatoses.

DNA Extraction and PCR Amplification

Genomic DNA was extracted from peripheral blood leukocytes using the E.Z.N.A.™ Blood DNA Kit (Omega, Norcross, GA, Cat. No. D3392) according to the manufacturer’s instructions. All 27 coding exons and flanking intronic sequences of ATP2C1 were amplified by PCR using previously published primer sequences.

PCR was performed in a 25 μL reaction volume containing 20 ng genomic DNA, 10 mM Tris–HCl (pH 8.3), 50 mM KCl, 3.0 mM MgCl₂, 0.01% gelatin, 0.2 mM dNTPs, 10 pmol of each primer, and 0.75 U HotStarTaq DNA polymerase (QIAGEN, Germany). The PCR cycling conditions were as follows: initial denaturation at 94°C for 5 min, followed by 35 cycles of denaturation at 94°C for 30s, annealing at 50°C for 30s (68°C for exon 27), and extension at 72°C for 45s, with a final extension at 72°C for 10 min.

Sequencing and Variant Analysis

PCR products were purified and sequenced using the BigDye Terminator Cycle Sequencing Ready Reaction Kit (Applied Biosystems, Foster City, CA) on an ABI 3730xl DNA Analyzer (Applied Biosystems). Sequence data were analyzed using Chromas software and aligned with the reference ATP2C1 sequence (NM_014382.5) from the NCBI database.

Identified variants were filtered against the 1000 Genomes Project, gnomAD, and ClinVar databases to exclude common polymorphisms. Variant pathogenicity was assessed according to the American College of Medical Genetics and Genomics (ACMG) guidelines. Co-segregation analysis was performed to confirm the association between the variant and the disease phenotype in the family.

Results

Clinical Findings

The family consisted of 23 individuals, including 2 male and 4 female affected patients (Figure 1). The proband (II:1), a 57-year-old female, presented with recurrent vesicular and erosive lesions on the neck, axillae, and inframammary folds since age 21. Lesions were exacerbated by heat, friction, and sweating, with seasonal worsening in summer. Physical examination revealed erythematous plaques, vesicles, and crusts in intertriginous areas (Figure 2A–C).

Figure 1.

Pedigree of Chinese family with Hailey-Hailey disease. The circles indicate females, the squares males. Blackened symbols represent affected individuals, open symbols represent unaffected individuals. The deceased individual is indicated by an oblique line. The proband in the family (individual II:1) is indicated by an arrow.

Figure 2.

Clinical findings and histological features. Vesicles and erythematous plaques in axillary fossa (A) and peri-umbilicus skin (B) mixed with areas of dry crusts on the buttocks (C). Skin biopsy shows dilapidated brick wall appearance (haematoxylin and eosin; original magnification × 100 (D) and ×400 (E)).

Skin biopsy from the axilla showed widespread suprabasal acantholysis, vesicle formation, and mild dyskeratosis, consistent with HHD (Figure 2D–E). Affected family members (second generation) had disease onset between ages 21 and 32; third- and fourth-generation individuals were under 25 and 5 years old, respectively, with no clinical manifestations.

Mutation Analysis

Direct sequencing of the ATP2C1 gene identified a novel heterozygous c.2395C>T transition in exon 25 in all affected family members (Figure 3A). This variant results in a premature termination codon at position 799 (p.R799X), leading to truncation of the hSPCA1 protein by 156 amino acids.

Figure 3.

Mutation analysis of ATP2C1 gene. Direct sequencing revealed a nonsense mutation, designated c.2395C>T (R799X) in exon 25 of the ATP2C1 gene (A), indicated by an arrow, in all patients of this family, compared to the normal individuals (B).

The c.2395C>T variant was absent in all unaffected family members and 100 unrelated healthy controls (Figure 3B). Co-segregation analysis confirmed that the variant was present only in affected individuals, consistent with autosomal dominant inheritance. According to ACMG guidelines, this nonsense variant is classified as “likely pathogenic” (PVS1+PS4).

Discussion

In this study, we identified a novel heterozygous nonsense mutation, c.2395C>T (p.R799X), in exon 25 of the ATP2C1 gene in a four-generation Chinese family with HHD. This mutation co-segregated with the disease phenotype and was absent in healthy controls, supporting its pathogenic role.

ATP2C1 mutations in HHD lead to loss of hSPCA1 function, disrupting Golgi calcium transport and intracellular calcium homeostasis.¹⁴ This impairs desmosome assembly and keratinocyte adhesion, resulting in acantholysis. Nonsense mutations like p.R799X induce premature protein truncation, likely triggering nonsense-mediated mRNA decay (NMD) and reducing functional hSPCA1 levels (haploinsufficiency). The p.R799X mutation truncates the C-terminal cytoplasmic domain of hSPCA1, which is critical for protein trafficking and calcium pump activity.

To date, over 100 ATP2C1 mutations have been reported in HHD patients worldwide, with no hotspot mutations identified.¹⁵ Environmental factors, such as anxiety, excessive body weight and outdoor occupations may significantly affect clinical presentation.^8,16 Most mutations are private, consistent with genetic heterogeneity. Our finding adds to the growing spectrum of ATP2C1 mutations in Chinese populations, aiding molecular diagnosis and genetic counseling. There is considerable clinical and histologic overlap between HHD and Darier’s disease (DD), two similarly inherited dermatosises.² However, 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 caused by mutations of ATP2A2 encoding a calcium transport ATPase of the sarco (endo)plasmic reticulum (SERCA2).^10,17

Genetic counseling is essential for at-risk family members, especially asymptomatic young individuals. Identification of the p.R799X mutation enables pre-symptomatic genetic testing, early intervention such as Botulinum toxin,¹⁸ and avoidance of triggering factors (eg., excessive sweating, skin trauma).

Disclosure

The authors declare no competing interests in this work.