Darier disease--novel mutations in ATP2A2 and genotype-phenotype correlation

Darier disease (DD) is with a frequency of up to 1 in 36,000 a relatively common genodermatosis with autosomal dominant inheritance and late age of onset. The progressive skin manifestations are variable, but often debilitating and disfiguring, and may be associated with a wide range of neuropsychiatric problems, such as epilepsy and depression. On histology, acantholysis and dyskeratosis are prominent findings, implicating impaired functionality of desmosomes. Recently, mutations in the ATP2A2 gene encoding SERCA2, a calcium pump of the endo/sacrcoplasmic reticulum, have been identified as the molecular basis of DD. This slow-twitched calcium ATPase has two splice variants, one of which is highly expressed in epidermis, and maintains low intracellular calcium levels by facilitating transport of cytosolic calcium into the endoplasmic reticulum. Thus, it may confer a direct effect on the established calcium-dependent assembly of desmosomes. We screened ATP2A2 in a cohort of 24 DD families using conformation sensitive gel electrophoresis and direct sequencing, and detected 14 distinct mutations, 9 of which were novel. The mutational spectrum included 9 missense mutations, 1 nonsense mutation, 3 small in-frame deletions, and a 19-basepair insertion. Mutations were scattered over the entire gene with a slight preponderance in the first 8 exons, and affected exclusively residues conserved among all SERCAs. In addition, we found 2 silent polymorphisms, 1 of which occurred in 4 unrelated families. Comparison of molecular data and phenotypic features, such as severity and type of disease, occurrence of mucosal involvement, or association with neuropsychiatric disorders, did not reveal an obvious genotype-phenotype correlation in our cohort.     

毛囊角化病ATP2A2基因突变的检测

目的:检测2例散发及2个家系毛囊角化病患者ATP2A2基因的突变。方法:采用聚合酶链反应扩增患者和健康对照个体ATP2A2基因的全部外显子,并进行DNA测序,检测该基因突变。结果:共发现1个新的点突变(TVS11+32 C→T)和2个已发现的错义突变(R131Q,N767S)。结论:毛囊角化病具有遗传异质性。     

一毛囊角化病家系ATP2A2基因突变的检测

目的 检测一毛囊角化病家系中ATP2A2基因的突变。方法 1例经组织病理结合临床诊断为毛囊角化病,采用聚合酶链反应和DNA测序方法对此家系进行基因突变情况检测。结果 家系中患者在ATP2A2上第1541位腺嘌呤A变为鸟嘌呤G,使编码ATP酶结合域第514位氨基酸由赖氨酸变为精氨酸,家系中未患病者及对照的健康人均不存在此突变。结论 K514R是引起该家系临床病变的一个新的特异突变,不是多态性变化。     

Mosaicism for ATP2A2 mutations causes segmental Darier's disease

Epidermal naevi are localized malformations of the epidermis consisting of verrucoid scaly papules and plaques following Blaschko's lines. Genetic mosaicism has been proposed to underlie the development of linear epidermal naevi. Rarely, epidermal naevi show acantholytic histology similar to Darier's disease, a dominantly inherited skin condition characterized by widespread warty papules. As patients with acantholytic dyskeratotic naevi often give a history of worsening after sun exposure and the lesions are typical of Darier's disease, numerous authors have proposed that these patients have segmental Darier's disease. The postulated relationship has not been proven, however. Recently, we identified ATP2A2, which encodes the sarco/endoplasmic reticulum Ca(2+) ATPase isoform 2 as the defective gene in Darier's disease. In this report, we investigated the involvement of ATP2A2 in acantholytic dyskeratotic naevi following Blaschko's lines in two patients. We identified a nonsense mutation (Y894X) in the first patient and a nonconservative glycine to arginine mutation at codon 769 (G769R) in the other patient. These mutations were present in affected skin, and were not detected in unaffected skin or in leukocytes. We conclude that acantholytic dyskeratotic naevi can arise from a somatic mutation in ATP2A2. These individuals are mosaics for the mutation, but the risk of transmission of generalized Darier's disease will depend on whether the germline is affected. Our findings provide further evidence that Blaschko's lines do reflect genetic mosaicism and that the term acantholytic dyskeratotic naevus might be replaced in the future by segmental Darier's disease induced by postzygotic mosaicism. J Invest Dermatol 115:1144-1147 2000     

一毛囊角化病家系ATP2A2基因突变检测

目的:检测一毛囊角化病家系的ATP2A2基因突变。方法:提取2例患者外周血DNA,采用聚合酶链式反应及DNA直接测序方法,检测患者ATP2A2基因突变。结果:该家系患者及其两女儿存在ATP2A2基因的碱基缺失突变,即ATP2A2基因第10个外显子1220位开始缺失了AA 2个碱基。而该家系中其他正常者未发现此突变。结论:ATP2A2基因第10个外显子1220delAA突变可能与该家系患者临床表型有关。     

毛囊角化病ATP2A2基因突变分析

目的检测毛囊角化病患者ATP2A2基因的突变。方法提取全部患者及健康对照个体的外周血DNA,采用聚合酶链反应扩增ATP2A2基因的全部外显子,并进行DNA测序。结果在收集到的2个家系和3例散发患者中共发现3个突变,包括1个缺失突变(1622delAACA),1个插入突变(180insCTTAA)和1个错义突变(698GT),均为未见报道的突变。在100例正常对照中均未发现上述突变。结论收集到的毛囊角化病患者存在ATP2A2基因的突变,这些突变可能会影响角质形成细胞中钙离子的转运,使表皮细胞的连接和分化出现异常。     

毛囊角化病九例ATP2A2基因突变研究

目的：检测9例毛囊角化病(Darier's disease, DD)患者的基因突变。方法：提取1家系中2例患者、7例散发患者及100名正常对照外周血基因组DNA,用Sanger测序检测9例DD患者ATP2A2的致病突变。对不携带ATP2A2突变的患者,应用全外显子组测序(WES)寻找可能导致该疾病的其他变异。364名健康对照被纳入突变筛选。可疑的变异通过Sanger测序进行确认。结果：通过Sanger测序,我们发现9例DD患者中有5例出现了ATP2A2突变,包括1例报道过的突变和3例新突变。在其余病例中,WES鉴定了四个ATP酶基因(ITPR3、ATP2B2、RYR1和PLCB1)中的4个变异,均参与钙信号通路。结论：本研究中发现了4个ATP2A2基因突变,其中3个为新发突变,丰富了ATP2A2基因突变谱,并提示四种ATP酶基因变异可能与DD相关。     

Novel mutations of ATP2A2 gene in Japanese patients of Darier's disease

Darier's disease (DD) is a rare, dominantly inherited skin disorder with abnormal keratinization and acantholysis. Recently, mutations of ATP2A2 encoding the sarco/endoplasmic reticulum Ca(2+)-ATPase type 2 isoform (SERCA2) have been reported in Caucasian DD families. In the present study, we examined the ATP2A2 gene mutations of three sporadic (AS1,AS3,AS4) and one familial (AS2) Japanese DD patients. Sequence analysis revealed that the patients had novel mutations, one nonsense mutation (AS1 (C613X)) and three single base changes leading to amino acid substitutions (AS2 (L321F), AS3 (I274V), and AS4 (M719I)). These results demonstrate that distinct ATP2A2 gene mutations are present in Japanese DD patients.     

A novel splice-site mutation of ATP2A2 gene in a Chinese family with Darier disease

Darier disease (DD; OMIM 124200) is a rare, autosomal dominant hereditary skin disorder characterized by abnormal keratinization and acantholysis. The causes of DD are defects in the ATP2A2 gene, which encodes the sarco/endoplasmic reticulum Ca²⁺ ATPase isoform 2 (SERCA2). The aim of this study was to report a novel splice-site mutation and to examine the relative quantity expression of ATP2A2 gene in a Chinese family with DD. Polymerase chain reaction (PCR) was carried out to amplify the exons and flanking intron boundaries of the ATP2A2 gene followed by direct sequencing. A novel splice-site mutation (IVS20-6T>A) was found in the family, which was confirmed by creating a novel HinfI (NEB Inc) recognition site and RT-PCR. Real-time quantitative PCR showed approximately 53 and 52% reduction of ATP2A2 expression of the proband and his father, respectively. The results support the proposition that haploinsufficiency is a common mechanism for the dominant inheritance of DD.     

Novel ATP2A2 mutations in a large sample of individuals with Darier disease

Darier disease (DD) is a rare autosomal dominantly inherited skin disorder caused by mutations in ATP2A2, which is expressed in both the skin and the brain and encodes for SERCA2. We have screened the coding regions of ATP2A2 in a total of 95 unrelated individuals with DD to identify the pathogenic mutations. We identified 66 potentially pathogenic mutations in ATP2A2 for 74 of the 95 individuals with DD of which 45 (68%) are thought to be novel. Forty‐nine (74%) are unique to an individual and 17 (26%) were found in more than one individual or overlap with previously identified variants. The results suggest that mutations in ATP2A2 may not be as family‐specific as first thought. The spectrum of mutations identified will inform understanding of the pathogenesis of DD.