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Concept: Genodermatoses

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Ectodermal dysplasias (EDs) are a large group of heritable complex conditions with more than 200 members and common clinical characteristics of anomalies of the hair, teeth, nails, and sweat glands with or without involvement of other organs (1) . Anhidrotic or hypohidrotic ectodermal dysplasia (EDA/ HED) is the most common form of EDs which is characterized by the clinical triad of hypotrichosis (sparse hair), abnormal or missing teeth (anodontia or hypodontia), and deficient sweating (hypohidrosis or anhidrosis) (2) . Different modes of inheritance have been described for HED. X-linked HED (OMIM: 305100) is caused by mutations in ectodysplasin A gene (EDA1), whereas mutations in the EDA receptor (EDAR) and EDAR-associated death domain (EDARADD) genes result in autosomal dominant (OMIM:129490) and autosomal recessive (OMIM: 224900) forms (3) .

Concepts: DNA, Genetics, Mutation, Point mutation, Genodermatoses, Hypohidrotic ectodermal dysplasia, Ectodermal dysplasia, EDA

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BACKGROUND: Detailed nationwide surveys of the epidemiologic and clinical characteristics of bullous congenital ichthyosiform erythroderma (BCIE) (novel synonym: keratinolytic ichthyosis) in a large population have not been performed previously to our knowledge. OBJECTIVE: We sought to estimate the number of patients with BCIE who visited dermatology departments in Japan in 2002 and to clarify the clinical and epidemiologic features of the disease. METHODS: A nationwide mail survey was sent to dermatology departments and consisted of an initial survey to estimate the number of individuals with BCIE and a second survey to obtain data on the clinical characteristics of these patients. RESULTS: The total number of patients with BCIE in Japan was estimated to be 55 (95% confidence interval, 35-75). Clinical data were able to be collected from 28 cases. Clinical manifestations included rash in 27 cases (96.4%), erythroderma in 19 cases (67.9%), and generalized blistering in 15 cases (57.7%). Approximately 75% of patients younger than 20 years showed generalized blistering. Hystrixlike scales were present in 8 female patients (57.1%), whereas large scales were present in 8 male patients (57.1%). Among the 19 patients for whom histopathological information was available, 17 (89.5%) showed granular degeneration. LIMITATIONS: Patients with BCIE who have few subjective symptoms may not have visited a dermatology department, potentially resulting in an underestimation of the number of patients with BCIE. CONCLUSION: Important epidemiologic and clinical information on characteristics of BCIE in Japan was obtained, including an estimate of the total number of patients with BCIE in Japan.

Concepts: Epidemiology, Statistics, Mathematics, Approximation, Estimation, Genodermatoses, Ichthyosis, Epidermolytic hyperkeratosis

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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.

Concepts: Protein, Mutation, Point mutation, Missense mutation, Nonsense mutation, Genodermatoses, Ichthyosis, IFAP syndrome

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Mutations in MBTPS2 have been reported to cause a broad phenotypic spectrum of X-linked genodermatoses, including IFAP (ichthyosis follicularis; atrichia and photophobia) syndrome (OMIM 308205) with or without BRESHECK (brain anomalies, retardation of mentality and growth, ectodermal dysplasia, skeletal malformations, Hirschsprung disease, ear deformity and deafness, eye hypoplasia, cleft palate, cryptorchidism, and kidney dysplasia/hypoplasia) syndrome, keratosis follicularis spinulosa decalvans (KFSD; OMIM 308800) and an X-linked form of Olmsted syndrome. We report a recurrent intronic mutation in MBTPS2 (c.671-9T>G) in a Chinese patient with the typical triad of IFAP syndrome (i.e. ichthyosis, atrichia and photophobia), along with pachyonychia, palmoplantar and periorificial keratoderma, which were reminiscent of Olmsted syndrome. Interestingly, this mutation was previously reported in two cases of IFAP without keratoderma, which suggests clinical heterogeneicity of the same mutation in MBTPS2. The concomitance of Olmsted syndrome-like features in this patient with IFAP may challenge the existence of the X-linked form of Olmsted syndrome as an independent condition.

Concepts: Keratoderma, Genetic disorders, Genodermatoses, Rare diseases, Ichthyosis, Palmoplantar keratodermas, IFAP syndrome, Keratosis follicularis spinulosa decalvans

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Mutations in XPD cause xeroderma pigmentosum (XP), XP and Cockayne syndrome (CS) crossover syndrome (XP/CS), trichothiodystrophy and cerebro-oculo-facio-skeletal syndrome (COFS). COFS represents the most severe end of the CS spectrum. This study reports two Japanese patients, COFS-05-135 and COFS-Chiba1, who died at ages of <1 year and exhibited typical COFS manifestations caused by XPD mutations p.[I619del];[R666W] and p.[G47R];[I619del], respectively. Two other cases of severe XP-D/CS (XP group D/CS), XP1JI (p.[G47R];[0]) and XPCS1PV (p.[R666W];[0]), died at ages <2 years. On the other hand, two cases of mild XP-D/CS, XP1NE (p.[G47R];[L461V;V716_R730del]) and XPCS118LV (p.[L461V;V716_R730del];[R666W]), lived beyond 37 years of age. p.I619Del and p.[L461V;V716_R730del] are functionally null; therefore, despite the differences in clinical manifestations, the functional protein in all of these patients was either p.G47R or p.R666W. To resolve the discrepancies in these XPD genotype-phenotype relationships, the p.[L461V;V716_R730del] allele was analyzed and we found that p.[L461V;A717G] was expressed from the same allele as p.[L461V;V716_R730del] by authentic splicing. Additionally, p.[L461V;A717G] could partially rescue the loss of XPD function, resulting in the milder manifestations observed in XP1NE and XPCS118LV.Journal of Human Genetics advance online publication, 26 February 2015; doi:10.1038/jhg.2015.18.

Concepts: Genetics, Evolution, DNA repair, Genodermatoses, Alternative splicing, Xeroderma pigmentosum, Cockayne syndrome

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The RASopathies are a group of disorders due to variations of genes associated with the Ras/MAPK pathway. Some of the RASopathies include neurofibromatosis type 1 (NF1), Noonan syndrome, Noonan syndrome with multiple lentigines, cardiofaciocutaneous (CFC) syndrome, Costello syndrome, Legius syndrome, and capillary malformation-arteriovenous malformation (CM-AVM) syndrome. In combination, the RASopathies are a frequent group of genetic disorders. This report summarizes the proceedings of the 4th International Symposium on Genetic Disorders of the Ras/MAPK pathway and highlights gaps in the field. © 2016 Wiley Periodicals, Inc.

Concepts: Genetics, Biology, Syndromes, Genetic disorders, Genodermatoses, Neurofibromatosis type I, Cardiofaciocutaneous syndrome, Fourth International

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Mutations in Ras/mitogen-activated protein kinase (Ras/MAPK) pathway genes lead to a class of disorders known as RASopathies, including neurofibromatosis type 1 (NF1), Noonan syndrome (NS), Costello syndrome (CS), and cardio-facio-cutaneous syndrome (CFC). Previous work has suggested potential genetic and phenotypic overlap between dysregulation of Ras/MAPK signalling and autism spectrum disorders (ASD). Although the literature offers conflicting evidence for association of NF1 and autism, there has been no systematic evaluation of autism traits in the RASopathies as a class to support a role for germline Ras/MAPK activation in ASDs.

Concepts: Gene, Genetics, Evolution, Autism, Asperger syndrome, Genetic disorders, Genodermatoses, Cardiofaciocutaneous syndrome

1

-Gastrointestinal (GI) and pancreatobiliary tracts contain a variety of neuroendocrine cells that constitute a diffuse endocrine system. Neuroendocrine tumors (NETs) from these organs are heterogeneous tumors with diverse clinical behaviors. Recent improvements in the understanding of NETs from the GI and pancreatobiliary tracts have led to more-refined definitions of the clinicopathologic characteristics of these tumors. Under the 2010 World Health Organization classification scheme, NETs are classified as grade (G) 1 NETs, G2 NETs, neuroendocrine carcinomas, and mixed adenoneuroendocrine carcinomas. Histologic grades are dependent on mitotic counts and the Ki-67 labeling index. Several new issues arose after implementation of the 2010 World Health Organization classification scheme, such as issues with well-differentiated NETs with G3 Ki-67 labeling index and the evaluation of mitotic counts and Ki-67 labeling. Hereditary syndromes, including multiple endocrine neoplasia type 1 syndrome, von Hippel-Lindau syndrome, neurofibromatosis 1, and tuberous sclerosis, are related to NETs of the GI and pancreatobiliary tracts. Several prognostic markers of GI and pancreatobiliary tract NETs have been introduced, but many of them require further validation.

Concepts: Cancer, Endocrinology, Neuroendocrinology, Genetic disorders, Genodermatoses, Endocrine system, World Health Organization, Multiple endocrine neoplasia

0

Hypohidrotic ectodermal dysplasia (HED) comprises a large group of inherited disorders of ectodermal structures, characterized by hypo-/anhidrosis, hypotrichosis and hypo-/oligo-/anodontia.

Concepts: Genodermatoses, Hypohidrotic ectodermal dysplasia, Ectodermal dysplasia

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Personality is a complex, yet partially heritable, trait. Although some Mendelian diseases like Williams-Beuren syndrome are associated with a particular personality profile, studies have failed to assign the personality features to a single gene or pathway. As a family of monogenic disorders caused by mutations in the Ras/MAPK pathway known to influence social behavior, RASopathies are likely to provide insight into the genetic basis of personality. Eighty subjects diagnosed with cardiofaciocutaneous syndrome, Costello syndrome, neurofibromatosis type 1, and Noonan syndrome were assessed using a parent-report BFQ-C (Big Five Questionnaire for Children) evaluating agreeableness, extraversion, conscientiousness, intellect/openness, and neuroticism, along with 55 unaffected sibling controls. A short questionnaire was added to assess sense of humor. RASopathy subjects and sibling controls were compared for individual components of personality, multidimensional personality profiles, and individual questions using Student tests, analysis of variance, and principal component analysis. RASopathy subjects were given lower scores on average compared to sibling controls in agreeableness, extraversion, conscientiousness, openness, and sense of humor, and similar scores in neuroticism. When comparing the multidimensional personality profile between groups, RASopathies showed a distinct profile from unaffected siblings, but no difference in this global profile was found within RASopathies, revealing a common profile for the Ras/MAPK-related disorders. In addition, several syndrome-specific strengths or weaknesses were observed in individual domains. We describe for the first time an association between a single pathway and a specific personality profile, providing a better understanding of the genetics underlying personality, and new tools for tailoring educational and behavioral approaches for individuals with RASopathies.

Concepts: Psychology, Genetics, Principal component analysis, Genetic disorders, Genodermatoses, Big Five personality traits, Trait theory, Cardiofaciocutaneous syndrome