Identification of a heterozygous p.Gly568Val missense mutation in the TRPV3 gene in a Japanese patient with Olmsted syndrome: In silico analysis of TRPV3

Olmsted syndrome is a very rare congenital disorder, characterized by palmoplantar keratoderma and periorificial keratotic lesions. Recently, TRPV3 was reported to be a causative gene of Olmsted syndrome. We identified a heterozygous missense mutation of TRPV3, c.1703G>T, p.Gly568Val, in a Japanese patient with Olmsted syndrome. To the best of our knowledge, this is the first report of a Japanese patient with Olmsted syndrome harboring a missense mutation in TRPV3. We conducted in silico analysis of TRPV3 to evaluate whether the p.Gly568Val leads to structural changes in the TRPV3 selectivity filter. The selectivity filter was shown to become dilated and hyperpermeable as a result of genetic mutation (p.Gly573Ser, p.Tr692Gly or p.Gly568Val) as well as after a change in temperature (300 K to 310 K). In silico analysis of TRPV3 could be a useful approach in predicting mutation‐induced activated states of ion channels, and thus enrich our understanding of the pathogenesis of Olmsted syndrome.     

Impact of the Gly573Ser substitution in TRPV3 on the development of allergic and pruritic dermatitis in mice

We reported that the Gly573Ser substitution in transient receptor potential vanilloid 3 (TRPV3) led to increased ion channel activity in keratinocytes and caused spontaneous hairlessness in DS-Nh mice. DS-Nh mice also develop allergic and pruritic dermatitis. As the hairless and dermatitis phenotypes were both inherited in an autosomal dominant fashion and could not be segregated from each other, we speculated that TRPV3(Gly573Ser) might be responsible for the dermatitis. Here, we constructed TRPV3(Gly573Ser) transgenic mice, with a putative promoter sequence in the 5' region of TRPV3, to investigate the involvement of TRPV3 in the development of specific types of dermatitis. These transgenic mice spontaneously developed dermatitis, whereas wild-type mice did not display this phenotype when maintained under the same conditions. Histological and serological analyses were carried out to better understand the clinical features of TRPV3(Gly573Ser) transgenic mice. A physiological study revealed that TRPV3(Gly573Ser) induced a higher nerve growth factor response to heat. Finally, C57BL-Nh mice were used to investigate the penetrance of the TRPV3(Gly573Ser) gene for dermatitis. Interestingly, C57BL-Nh mice developed spontaneous scratching behavior, separately from the development of dermatitis. We propose that TRPV3(Gly573Ser) is a cause of pruritus and/or dermatitis associated with scratching, and suggest that TRPV3 may represent a therapeutic target in pruritic dermatitis.     

Association of a mutation in TRPV3 with defective hair growth in rodents

DS-Nh mice and WBN/Kob-Ht rats are spontaneous hairless mutant rodent strains. These animals develop spontaneous dermatitis under normal conditions. The non-hair Nh and Ht phenotypes are inherited in an autosomal dominant fashion, and the Nh mutation possesses a high potency for penetration. We previously reported that genes involved in dermatitis and hairlessness did not segregate from each other. Here, we carried out genetic analysis to identify the genes responsible for these hairless mutations. An amino-acid substitution at the same position in one gene was detected in DS-Nh mice and WBN/Kob-Ht rats: Gly573 to Ser (Nh mutation) or Gly573 to Cys (Ht mutation), located in the transient receptor potential (TRP) cation channel subfamily V member 3 (TRPV3) gene. Mutated TRPV3 was expressed in skin keratinocytes of DS-Nh mice. Histopathological analyses revealed that mast cells in skin lesions were increased in both rodents compared to their age-matched parent strains, and that this may partially be due to hairlessness and dermatitis. We concluded that TRPV3 was the gene responsible for Nh and Ht mutations, and that mutation in TRPV3 possibly correlated with increased mast cell numbers.     

Two familial cases of Olmsted‐like syndrome with a G573V mutation of the TRPV3 gene

Olmsted syndrome (OS) is a rare disease, characterized by symmetrical, sharply defined, hyperkeratotic, mutilating plaques on the palms and soles, which are associated with periorificial keratotic plaques. Other clinical manifestations of OS include diffuse alopecia, leucokeratosis of the oral mucosa, onychodystrophy, hyperkeratotic linear streaks, follicular hyperkeratosis and constriction of the digits. A recent study identified de novo mutations in the gene for transient receptor potential vanilloid 3 (TRPV3), causing constitutive activation of the TRPV3 channel, as a cause of OS. We report familial inheritance of OS in a family from Mongolia, which was caused by a previously undescribed G573V point mutation in TRPV3. To date, mutations in the G573 residue of TRPV3 have been reported in seven cases of OS: G573S in five cases, and G573C and G573A mutations in one case each. We present a Mongolian familial case of G573V point mutation in TRPV3.     

Olmsted syndrome in an Iranian boy with a new de novo mutation in TRPV3

Olmsted syndrome (OS) is a rare congenital skin disorder characterized by palmoplantar keratoderma, periorificial hyperkeratotic lesions and alopecia. Constriction of digits, onychodystrophy and pruritus may also occur. Recently, pathogenic heterozygous mutations in TRPV3 were identified, with most cases showing de novo dominant inheritance. We present the clinical and molecular features of OS in a 10‐year‐old Iranian boy. He had mutilating palmoplantar keratoderma, periorificial keratotic plaques, diffuse alopecia and constriction bands (pseudoainhum), which led to autoamputation of two digits. TRPV3 was sequenced and a new de novo heterozygous missense mutation, c.2076G>C (p.Trp692Cys), was identified. This case illustrates the characteristic clinical features and complications that can present in OS, and further expands the molecular basis of this genodermatosis.     

Impact of TRPV3 on the development of allergic dermatitis as a dendritic cell modulator

The transient receptor potential channel vanilloid subfamily V member 3 (TRPV3), which functions as a thermosensor in keratinocytes, plays an important role in the development of allergic and itchy dermatitis in rodents. Although real‐time PCR analysis using lesional and non‐lesional skin samples from patients with atopic dermatitis showed that TRPV3 was expressed in lesional skin, the role that TRPV3 plays in patients with dermatitis is still relatively obscure. Here, we determined whether TRPV3 was a dendritic cell (DC) modulator using DS‐Nh mice with a gain‐of‐function mutation in TRPV3 (TRPV3Gly573Ser), because increasing skin temperature is associated with the modulation of dermal dendritic cells (DCs). Interestingly, increased responses to haptens by skin and DCs were observed in DS‐Nh mice compared with those from DS mice with wild‐type TRPV3. Increased thymic stromal lymphopoietin (TSLP) responses were also observed in keratinocytes from DS‐Nh mice compared with those from DS mice. Taken together, we propose that the DS‐Nh mouse is a good model to use in order to better understand the role of this orphan channel and that TRPV3 may represent a new therapeutic target in certain types of dermatitis through the control of DCs.     

Sjogren-Larsson综合征ALDH3A2基因突变研究

目的 检测2例以先天性鱼鳞病、智力发育迟缓及痉挛性截瘫为主要表现的Sj?觟gren-Larsson综合征患者的ALDH3A2基因突变情况。 方法　2例分别为2岁女性及1.5岁男性儿童,家族中均无类似疾病。提取2例患者及其6例相关亲属（每例患儿的父母及哥哥）外周血DNA,采用PCR扩增ALDH3A2基因编码区的全部外显子及其侧翼序列并测序。同时随机抽取100例无关健康人外周血基因组DNA作对照。结果基因检测发现,例1的ALDH3A2基因发生c.325G>A纯合突变,导致氨基酸出现p. Gly109Arg改变,其父母及其未受累的兄长为该突变的杂合携带者。例2的ALDH3A2基因发生c.1157A>G及c.1294A>T复合杂合突变,导致氨基酸出现p. Asn386Ser及p.Arg432X改变,突变分别来自父母。100例健康对照者均未见相同突变。结论 在2例Sj?觟gren-Larsson综合征患者中检测到ALDH3A2基因的p. Gly109Arg纯合突变及p. Asn386Ser与p. Arg432X复合杂合突变,该基因突变可能与患者临床表型相关。 【关键词】 Sjogren-Larsson综合征; 鱼鳞病; 突变; ALDH3A2     

Novel and recurrent COL7A1 mutation in a Polish population

Dystrophic Epidermolysis Bullosa (DEB) is a rare bullous genodermatosis caused by mutations in COL7A1, which encodes collagen type VII, the main component of anchoring fibrilis. DEB is inherited in an autosomal recessive and dominant manner, depending on the mutation type and localization. The aim of this study was to update the spectrum and frequency of COL7A1 mutations in a cohort of 42 Polish DEB patients. Using direct sequencing strategy we identified 25 different mutations, which gave us a detection rate of about 88%. In total, thirteen novel variants were identified, including three de novo mutations (p.G2680S, p.G2043R and p.Gly2064_Arg2069del). The panel of recessively inherited DEB causing recurrent mutations comprise of five variants: c.425A>G, c.682+1G>A, p.R2069C, p.W796X and, unreported before, c.7154delC, which accounts for about 59% of all mutated alleles in this group. In the dominant type of DEB, only p.G2043R was found to be recurrent and it was identified in 50% patients. Our results give further insight into the pathogenesis and epidemiology of DEB.     

OSMR基因突变与原发性皮肤淀粉样变174例的临床表型分析

目的探讨OSMR基因突变与原发性皮肤淀粉样变(PCA)临床表型的相关性。方法收集174例PCA患者和52例正常对照组的外周血进行OSMR基因11~15号外显子的一代测序,并对其临床资料进行统计、分析。结果 174例PCA患者中,35.63%的患者有家族史,64.37%的患者无家族史,平均发病年龄为(31±12.69)岁,20~29岁为其发病的高峰年龄段(31.03%);苔藓样皮肤淀粉样变(LA)(75/56)与斑状皮肤淀粉样变(MA)(16/27)中的男女比例差异有统计学意义(P=3.51×10^-2);LA患者较MA患者更易伴发瘙痒(P=1.60×10^-2);174例PCA患者中,36.78%有OSMR基因突变,其中OSMR基因p.Gly513Asp突变位点占总突变的84.38%,为高频突变位点;相对于无OSMR基因突变的PCA患者的发病年龄(32.63±13.50)岁来说,有OSMR基因突变的PCA患者的发病年龄(28.58±10.90)岁更低(P=4.30×10^-2);对有OSMR基因突变(包括p.Gly513Asp、p.Gly513Asp纯合位点、p.Gly513Asp杂合位点等)与无OSMR基因突变的PCA患者的临床资料进行比较分析发现,家族史(P<1.00×10^-3)、性别(P=4.20×10^-2)、皮损范围(P=1.50×10^-2)差异具有统计学意义;对有OSMR基因p.Gly513Asp位点突变(纯合突变及杂合突变)与无OSMR基因突变的PCA患者的临床资料进行比较分析,发现家族史(P=1.00×10^-3)、性别(P=0.02)、皮损范围(P=6.00×10^-3)差异具有统计学意义;有OSMR基因突变与无OSMR基因突变相比,患者的临床分型(LA与MA)、瘙痒比例差异无统计学意义(P>0.05)。结论 OSMR基因突变(p.Gly513Asp纯合位点)与PCA患者的家族史、性别、皮损范围、发病年龄具有相关性。     

表皮松解性掌跖角化病一家系KRT9基因突变检测

目的：检测一表皮松解性掌跖角化病(epidermolytic palmoplantar keratoderma,EPPK)家系中患者及其家族成员的KRT9基因突变。方法：收集该EPPK家系先证者及其家族成员临床资料,提取他们及100例无亲缘关系的健康对照外周血DNA,PCR扩增KRT9基因编码区的全部外显子及其侧翼序列,对产物直接测序,同时进行突变点的功能预测。结果：该家系所有患者的KRT9基因1号外显子第482位碱基均发生错义突变c.482A>G(p.Asn161Ser)。家系中未患病者及100名正常对照中均未发现此突变。SIFT和Polyphen-2软件预测c.482A>G(p.Asn161Ser)突变为有害变异位点。结论：KRT9基因的突变c.482A>G(p.Asn161Ser)可能是导致该家系发生表皮松解性掌跖角化病的原因。     

A heterozygous frameshift mutation in the V1 domain of keratin 5 in a family with Dowling-Degos disease

Dowling-Degos disease (DDD) is an autosomal-dominant genodermatosis characterized by reticulate pigmentation of the flexures. By direct DNA sequencing, we have identified a frameshift mutation in exon 1 of KRT5 in the proband from an extended Spanish DDD kindred. Cloning of PCR products confirmed that this was a 2-bp deletion mutation, designated c.442delAG, leading to a premature termination codon in the V1 domain of the K5 polypeptide, designated p.S148fsX30. These data confirm that haploinsufficiency for K5 causes DDD and points to a prominent role for the keratin intermediate filament cytoskeleton within basal keratinocytes in epidermal pigment biology.     

Family of hereditary fibrosing poikiloderma with tendon contractures,myopathy and pulmonary fibrosis caused by a novel FAM111B mutation

Hereditary fibrosing poikiloderma with tendon contractures, myopathy and pulmonary fibrosis (POIKTMP) is a recently identified autosomal dominant genetic syndrome with mutations in FAM111B. Herein, we report a 14‐month‐old girl who presented with progressive poikiloderma on the face. Her 24‐year‐old mother had an identical facial poikiloderma, hyperpigmentation, mottling and Blaschko line hypopigmentation on the trunk and limbs, as well as severe tendon contractures. Next‐generation sequencing based on a targeted gene capture panel revealed a missense mutation in the FAM111B gene p.Phe416Ser (c.1247T>C). Her mother had the same mutation as the proband. Moreover, this mutation was absent in the unaffected father and maternal grandparents. Based on the clinical manifestations and genetic analysis, the proband and her mother were diagnosed with POIKTMP. Protein modeling indicated that the mutation p.Phe416Ser dramatically changed the protein structure, especially its structural stability, and affected the protein function. This is the first report of POIKTMP in a Chinese family due to a novel FAM111B mutation. Furthermore, we have reviewed the genotype–phenotype correlation, differential diagnoses and management of POIKTMP.     

胫前显性营养不良型大疱性表皮松解症基因突变研究

目的 探讨Ⅶ型胶原基因（COL7A1）在胫前显性营养不良型大疱性表皮松解症（DDEB-Pt）发病中的意义。 方法 收集中国汉族1例DDEB-Pt散发患者及其家庭成员和100例健康对照的外周血标本,用改良盐析法提取外周静脉血中的基因组DNA,通过PCR反应扩增和测序进行序列分析。 结果 测序结果显示,COL7A1基因73号外显子的第6109位碱基鸟嘌呤（G）转化为腺嘌呤（A）,使得三螺旋区第2037位密码子由GCT变成ACT,编码氨基酸由甘氨酸（Gly）变为精氨酸（Arg）,即c.G6109A（p.Gly2037Arg）甘氨酸替换突变。 结论 COL7A1 基因甘氨酸替换突变为致病性突变,是一新发突变。     

Identical glycine substitution mutations in type VII collagen may underlie both dominant and recessive forms of dystrophic epidermolysis bullosa

Autosomal dominant and recessive forms of dystrophic epidermolysis bullosa (DEB) result from mutations in the type VII collagen gene (COL7A1). Although paradigms have emerged for genotype/phenotype correlation in DEB, some pathogenic mutations in COL7A1, notably glycine substitutions within the type VII collagen triple helix, may lead to diagnostic difficulties, since certain glycine substitutions can result in either dominant or recessive mutant alleles. Delineation of glycine substitution mutations into two discrete groups, however, is made difficult by observations that, for some particular glycine substitutions in type VII collagen, the same mutation can result in both dominant and recessive disease. In this report we describe four further glycine missense mutations: p.Gly1483Asp, p.Gly1770Ser, p.Gly2213Arg and p.Gly2369Ser, which can lead to either dominant or recessive DEB, and which result in a spectrum of clinical abnormalities. We also identify a further 30 new glycine substitution mutations that cause either dominant or recessive DEB, but not both. In screening the COL7A1 gene for mutations in individuals with DEB our data highlight that delineation of glycine substitutions in type VII collagen has important implications for genetic counselling.     

A new, recurrent mutation of GJB3 (Cx31) in erythrokeratodermia variabilis

BACKGROUND: Erythrokeratodermia variabilis (EKV) is an autosomal dominant or recessive genodermatosis characterized by the coexistence of randomly occurring, transient, erythematous patches and hyperkeratosis of the skin. The disorder has been mapped to chromosome 1p35.1 but is genetically heterogeneous. EKV may be caused by pathogenic mutations in one of two neighbouring connexin genes, GJB3 and GJB4, encoding the gap junction proteins Cx31 and Cx30.3, respectively. Twelve distinct mutations identified to date cluster either at the cytoplasmic amino-terminus or in the four transmembrane domains. OBJECTIVES: To report a large family with EKV and an unrelated sporadic case. METHODS: DNA amplification and mutation analysis, followed by denaturing high-performance liquid chromatography to confirm the segregation of the mutations in the two families with EKV. RESULTS: A novel, recurrent GJB3 mutation (625C-->T; L209F) was identified in the family with EKV and in the unrelated sporadic case. CONCLUSIONS: This mutation is the first to affect a conserved residue in the cytoplasmic carboxy-terminus of any connexin gene with a cutaneous phenotype, emphasizing its structural and/or functional importance.     

Novel Mutation of the NCSTN Gene Identified in a Chinese Acne Inversa Family

Acne inversa is a chronic inflammatory follicular disease with autosomal dominant inheritance. In recent years, many functional mutations in the NCSTN genes have been identified as the cause of familial acne inversa. Herein, we recruited four patients and seven unaffected individuals from a Chinese family and performed Sanger sequencing of the NCSTN gene. One novel frameshift mutation, c.450_459del (p.Ser 151GlnfsX48), was identified in exon 5 of the NCSTN gene. Three normal-looking children carrying the mutation were proven to be patients. We also presented a literature review from previous studies of acne inversa, suggesting that NCSTN is a hotspot gene for acne inversa. Most affected individuals experienced onset in adolescence. We confirmed the diagnosis in this family based on the mutation. This finding will help expound the relationship between the NCSTN gene and the pathogenesis of acne inversa and emphasize the value of genetic diagnosis in monogenic disorder.     

显性营养不良型大疱性表皮松解症COL7A1基因突变分析

Objective: Dystrophic epidermolysis bullosa is an autosomal dominant or recessive disorder caused by mutations in the gene encoding type Ⅶ collagen (COL7A1 gene). To detect the mutation of COL7A1 in a DEB family. Methods: We performed full exon sequencing on DNA of the proband, and verified the COL7A1 mutation site of her sister by Sanger sequencing. Results: The proband and her sister had the same COL7A1 genotype, and the point mutation on exon 86 was c.6761G>A (p.Gly2254Glu). Conclusion: A new mutation locus of DEB family COL7A1 gene is found, which has not been reported in China at present. © 2022 China Journal of Leprosy and Skin Diseases. All rights reserved.     

Two novel mutations of the NCSTN gene in Chinese familial acne inverse

Background Acne inversa (AI; MIM 142690), or hidradenitis suppurativa (HS), is a type of autosomal‐dominant genodermatosis caused by mutations in γ‐secretase. The complex of γ‐secretase is a transmembrane protease that catalyses the cleavage of a set of membrane proteins and is comprised of four subunits encoded by four genes, including PSEN1, PSENEN, NCSTN and APH1. However, mutations associated with AI vary significantly, and it is important to define the specific mutation with a particular AI patient. Objective To determine specific mutations in the γ‐secretase gene associated with two Chinese AI families. Methods Two families of three generations with apparent AI symptoms were examined through proband analysis. Genomic DNAs of the family members and a cohort of 100 healthy individuals were isolated and subjected to polymerase chain reaction (PCR) and direct DNA sequencing. Results Two heterozygous missense mutations, c.647A>C (p.Q216P) in the exon 6, and c.223G>A (p.V75I) in the exon 3 of the NCSTN gene, were identified in the two families respectively. No mutations were found in 100 healthy individuals. Conclusions We have identified two novel mutations within the NCSTN gene associated with AI.     

A newly identified missense mutation of the HR gene is associated with a novel, unusual phenotype of Marie Unna Hereditary Hypotrichosis 1 including limb deformities

Marie Unna Hereditary Hypotrichosis 1 (MUHH1; OMIM 146550), a rare monogenic condition characterized by the development of sparse, twisted hair or complete hair loss, is the consequence of mutations located in the hairless (HR) gene. We have identified a 68-year-old Hungarian woman affected by alopecia universalis and limb deformities of all four extremities. Direct sequencing of the coding regions of the HR gene revealed a novel missense mutation in the third exon of the HR gene (c.974G/A, p.Gly325Asp). The affected family member carried the mutation in a heterozygous form, while the only available, clinically unaffected family member (the son of the patient) and the unrelated controls carried the wild type sequence. The association between the presence of HR gene mutations and the development of alopecia is well-established, however, further studies are needed to elucidate the putative role of this novel HR mutation in the development of limb deformities.     

Mutation S233L in the 1B domain of keratin 1 causes epidermolytic palmoplantar keratoderma with "tonotubular" keratin

Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant genodermatosis characterized by epidermolytic hyperkeratosis restricted to the palm and sole epidermis. The disorder is normally associated with dominant-negative mutations in the keratin 9 (K9) gene; however, a small number of cases have been reported where causative mutations were identified in the K1 gene. Here, we present two unrelated Dutch EPPK families with striking ultrastructural findings: tubular keratin structures in the cytoplasm of suprabasal cells. Similar structures were reported previously in a German EPPK family and were termed "tonotubular" keratin. After excluding the involvement of the K9 gene by complete sequencing, we identified a novel mutation, S233L, at the beginning of the 1B domain of K1 in both families. Protein expression studies in cultured cells indicated pathogenicity of this mutation. This is the first report of a genetic defect in this domain of K1. The unusual gain-of-function mutation points to a subtle role of the 1B domain in mediating filament-filament interactions with regular periodicity.