TGM5 Mutations Impact Epidermal Differentiation in Acral Peeling Skin Syndrome

Acral peeling skin syndrome (APSS) is an autosomal recessive skin disorder characterized by acral blistering and peeling of the outermost layers of the epidermis. It is caused by mutations in the gene for transglutaminase 5, TGM5. Here, we report on clinical and molecular findings in 11 patients and extend the TGM5 mutation database by four, to our knowledge, previously unreported mutations: p.M1T, p.L41P, p.L214CfsX15, and p.S604IfsX9. The recurrent mutation p.G113C was found in 9 patients, but also in 3 of 100 control individuals in a heterozygous state, indicating that APSS might be more widespread than hitherto expected. Using quantitative real-time PCR, immunoblotting, and immunofluorescence analysis, we demonstrate that expression and distribution of several epidermal differentiation markers and corneodesmosin (CDSN) is altered in APSS keratinocytes and skin. Although the expression of transglutaminases 1 and 3 was not changed, we found an upregulation of keratin 1, keratin 10, involucrin, loricrin, and CDSN, probably as compensatory mechanisms for stabilization of the epidermal barrier. Our results give insights into the consequences of TGM5 mutations on terminal epidermal differentiation.     

Acral Peeling Skin Syndrome Resulting from a Homozygous Nonsense Mutation in the CSTA Gene Encoding Cystatin A

Acral peeling skin syndrome (APSS) is a clinically and genetically heterogeneous disorder. We used whole‐exome sequencing to identify the molecular basis of APSS in a consanguineous Jordanian‐American pedigree. We identified a homozygous nonsense mutation (p.Lys22X) in the CSTA gene, encoding cystatin A, that was confirmed using Sanger sequencing. Cystatin A is a protease inhibitor found in the cornified cell envelope, and loss‐of‐function mutations have previously been reported in two cases of exfoliative ichthyosis. Our study expands the molecular pathology of APSS and demonstrates the value of next‐generation sequencing in the genetic characterization of inherited skin diseases.     

Acral Peeling Skin Syndrome: A Case of Two Brothers

Abstract:   We report two brothers of Middle Eastern descent with consanguineous parents who present with numerous fragile, flaccid blisters on the hands and feet. In addition to spontaneous peeling, they can manually peel skin from acral areas without pain. The symptoms worsen with warm temperatures, excessive water exposure, and perspiration. Two biopsies from flaccid blisters on the feet were taken from the older brother, which revealed cleavage at the level of the stratum corneum. A diagnosis of acral peeling skin syndrome was made.     

Immunoglobulin A Nephropathy in Association with Generalized Inflammatory Peeling Skin Syndrome

We describe an 8‐year‐old girl born to second‐degree consanguineous parents with complaints of recurrent episodes of hematuria for 6 months. She had generalized peeling of the skin since birth and recurrent purulent cutaneous infections. The clinical presentation and histopathology of the skin biopsy specimen were consistent with the inflammatory variant of peeling skin syndrome (PSS). She also had a single ventricle with pulmonary stenosis, for which a bidirectional Glenn shunt had been placed. The renal biopsy specimen showed immunoglobulin A (IgA) nephropathy. She responded well to enalapril and steroids, with a decrease in proteinuria. IgA nephropathy has not been previously reported in PSS. Complications such as IgA nephropathy in children with PSS would help to further delineate the diverse clinical presentations and the clinical course of this rare dermatosis. We discuss the mechanisms that could explain this hitherto unreported association.     

寻常型鱼鳞病一家系Filaggrin基因突变检测

目的探讨一家系寻常型鱼鳞病(ichthyosis vulgaris,IV)丝聚合蛋白(filaggrin,FLG)基因的突变。方法提取IV患者及其家庭成员和100例健康对照者基因组DNA,采用PCR及直接测序法,对FLG基因已报道的13个突变位点(3321delA,441delA,1249insG,E1795X,S3296X,R501X,2282del4,R2447X,S2889X,7945delA,3702delG,Q2417X,R4307X)进行测序。结果三代7位成员中4例IV患者同时检测到FLG(441delA)基因突变。结论患者FLG(441delA)基因突变可能导致其发病。     

遗传性对称性色素异常症一家系DSRAD基因的突变

目的检测一个遗传性对称性色素异常症家系中的DSRAD基因突变情况。方法收集了一个遗传性对称性色素异常症家系的外周血标本,用聚合酶链反应(PCR)扩增DSRAD基因的全部15个外显子并测序,检测家系中的患者及正常人和100例无关正常人的DSRAD基因。结果家系中所有患者的DSRAD基因存在外显子3的杂合缺失突变:c.1615delG。家系中的正常人及100例无关正常人未发现此突变。结论发现DSH家系患者DSRAD基因的一个新的突变。     

Novel MBTPS2 Missense Mutation in the N‐Terminus Transmembrane Domain in a Patient with Ichthyosis Follicularis,Alopecia, and Photophobia Syndrome

Ichthyosis follicularis, alopecia, and photophobia (IFAP) syndrome is an X‐linked dominant condition characterized by the triad of ichthyosis follicularis, alopecia, and photophobia caused by mutations in the MBTPS2 gene. Herein we describe a proband with IFAP syndrome with mild cutaneous manifestations and a novel MBTPS2 mutation in the N‐terminal transmembrane domain.     

Recessive Bullous Dermolysis of the Newborn in Preterm Siblings with a Missense Mutation in Type VII Collagen

Bullous dermolysis of the newborn is a dominant or recessive inherited subtype of dystrophic epidermolysis bullosa characterized by the tendency to spontaneously stop blistering within the first months of life. Here we report two siblings with bullous dermolysis of the newborn who were born prematurely and have a novel recessive mutation, p.Pro2259Leu, in the triple helix domain of type VII collagen. We discuss the possible relationship between genotype and prematurity and clinical manifestations in these patients.