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BACKGROUND: Therapeutic patient education (TPE) is recommended for children with atopic dermatitis (AD), but no consensus has been reached on the optimal tailoring of delivery. While repeated multidisciplinary group education sessions have shown effectiveness, the benefits of one-on-one educational interventions led by nurses for children with AD have not yet been assessed. OBJECTIVES: To assess the benefits of additional, well-structured, 1-h nurse-led individual TPE interventions in children with AD and their families compared with standard care alone. METHODS: Children with moderate-to-severe AD and their parents were randomized to receive a 1-h nurse-led education session in addition to standard care vs. standard care alone. The primary outcome was the area under the curve (AUC) of the SCORing of Atopic Dermatitis index (SCORAD) from baseline to week 24 (lower AUC values represent better long-term control of the disease). RESULTS: In our study, 176 patients were randomized across 11 centres, and 153 were included in the full analysis set. The mean (SD) age was 4.47 (4.57) years. By week 24, there were no significant differences in the AUCs of the SCORAD between the two groups (P = 0.3). Secondary outcomes including patient-reported severity and quality of life [AUCs of the patient-oriented SCORAD (PO-SCORAD) and Infants' Dermatitis Quality of Life Index (IDLQI), Children's Dermatitis Quality of Life Index (CDLQI) and Family Dermatitis Quality of Life Index (FDLQI)] were not significantly different between the two groups. The only significant change observed in the intervention group, when compared with the one receiving standard care, was a decrease in topical steroid phobia, as assessed by the topical corticosteroid phobia (TOPICOP) score. Prespecified subgroup analyses showed that disease severity in the intervention group was significantly lower throughout the study, compared with the standard-care group when participants had moderate AD at baseline (n = 47); while participants with severe AD at baseline (n = 106) did not show benefit from the intervention. Participants showed no additional benefit from the intervention regardless of age group. CONCLUSIONS: This study did not show any additional effectiveness, in long-term severity control, of a 1-h nurse-led TPE intervention in children with AD treated with standard care, compared with those treated with standard care alone. However, it should be noted that the intervention reduced the fear of using topical steroids and may be beneficial for patients in the subgroup with moderate AD.
Atopic dermatitis (AD), also known as atopic eczema, is a chronic relapsing disease that affects 715% of children worldwide. Therapeutic patient education (TPE) is recommended for children with AD, but no agreement has been reached on the best way to tailor delivery. While repeated multidisciplinary group education sessions in a hospital setting have been found effective, this type of intervention requires a lot of resources and is time-consuming. To assess the benefits of TPE in children with AD, researchers in France carried out this study with children with moderate-to-severe AD, to compare a 1-hour nurse-led education session in addition to standard care vs. standard care alone. The main aim of this research was to assess the effectiveness of a TPE intervention over a period of 6â months, using a measurement tool called the SCORAD (SCORing of Atopic Dermatitis index). We found no additional benefits in terms of long-term severity control and quality of life at 6â months of a 1-hour nurse-led education intervention in children with AD treated with standard care. However, it should be noted that the intervention reduced the fear of using topical steroids and may be beneficial for people in the moderate AD subgroup.
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Dermatite Atópica , Educação de Pacientes como Assunto , Humanos , Dermatite Atópica/terapia , Dermatite Atópica/enfermagem , Masculino , Feminino , Pré-Escolar , Criança , Resultado do Tratamento , Qualidade de Vida , Pais/educação , LactenteRESUMO
BACKGROUND: Data on dermatological manifestations of Costello syndrome (CS) remain heterogeneous and lack in validated description. OBJECTIVES: To describe the dermatological manifestations of CS; compare them with the literature findings; assess those discriminating CS from other RASopathies, including cardiofaciocutaneous syndrome (CFCS) and the main types of Noonan syndrome (NS); and test for dermatological phenotype-genotype correlations. METHODS: We performed a 10-year, large, prospective, multicentric, collaborative dermatological and genetic study. RESULTS: Thirty-one patients were enrolled. Hair abnormalities were ubiquitous, including wavy or curly hair and excessive eyebrows, respectively in 68% and 56%. Acral excessive skin (AES), papillomas and keratotic papules (PKP), acanthosis nigricans (AN), palmoplantar hyperkeratosis (PPHK) and 'cobblestone' papillomatous papules of the upper lip (CPPUL), were noted respectively in 84%, 61%, 65%, 55% and 32%. Excessive eyebrows, PKP, AN, CCPUL and AES best differentiated CS from CFCS and NS. Multiple melanocytic naevi (>50) may constitute a new marker of attenuated CS associated with intragenic duplication in HRAS. Oral acitretin may be highly beneficial for therapeutic management of PPHK. No significant dermatological phenotype-genotype correlation was determined between patients with and without HRAS c.34G>A (p.G12S). CONCLUSIONS AND RELEVANCE: This validated phenotypic characterization of a large number of patients with CS will allow future researchers to make a positive diagnosis, and to differentiate CS from CFCS and NS.
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BACKGROUND: Our objective was to describe the clinical, histological characteristics, and disease outcome of a cohort of mycosis fungoides (MF) diagnosed during childhood including disease status at adulthood. METHODS: This is a retrospective multicentre survey of patients aged under 18 years at diagnosis with histologically confirmed MF. Patients' clinical and histological characteristics, treatments, and disease outcome (for patients followed for more than 12 months) were analysed. RESULTS: Forty-six patients were included (median age at diagnosis: 11 years; M:F sex ratio: 3:1) with 39 (85%) followed for at least 12 months. Thirty-nine patients (85%) had stage I MF. Hypopigmented patches were observed in 48% and folliculotropism in 43% patients. Immunophenotype of the skin infiltrate was predominantly CD8+ in 17% of patients. Initial management included a wait-and-see strategy in 6/39 (15%), skin-directed treatment in 27 (69%), and systemic treatment in 6 (15%) patients, respectively, with partial or complete clinical response (PR or CR) observed in 28 patients (72%). 14/39 patients (36%) relapsed after initial response. After a median follow-up period of 54 months, disease status at last news was PR or CR in 31/39 (79%), stable disease in 6 (15%), and progression in 2 (5%) patients. Histological transformation was observed in 3/39 (8%). Of the 15 patients followed until adulthood, 13 (87%) had persistent MF. DISCUSSION: This survey confirms the high frequency of hypopigmented and folliculotropic lesions and of CD8+ immunophenotype compared to adult MF patients. The long-term course is usually indolent but transformation may occur sometimes long after disease onset and the disease may persist during adulthood.
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Hipopigmentação , Micose Fungoide , Neoplasias Cutâneas , Adulto , Humanos , Criança , Adolescente , Idoso , Neoplasias Cutâneas/diagnóstico , Micose Fungoide/diagnóstico , Estudos Retrospectivos , Hipopigmentação/tratamento farmacológico , Hipopigmentação/patologia , Administração CutâneaRESUMO
The purpose of the study is to highlight clinical signs that are either suggestive of or against the diagnosis of AHEI to improve diagnosis and management. The medical records of children under 3 years old diagnosed with AHEI were retrospectively reviewed. Clinical data and photographs were reviewed by three independent experts, and the cases were classified as probable, doubtful, or unclear AHEI. Of the 69 cases of children diagnosed with AHEI included in 22 centers, 40 were classified as probable, 22 as doubtful, and 7 as unclear. The median age of patients with probable AHEI was 11 months [IQR 9-15], and they were in overall good condition (n = 33/40, 82.5%). The morphology of the purpura was targetoid in 75% of cases (n = 30/40) and ecchymotic in 70% of cases (n = 28/40) and affected mostly the legs (n = 39/40, 97%), the arms (n = 34/40, 85%), and the face (n = 33/40, 82.5%). Edema was observed in 95% of cases and affected mostly the hands (n = 36/38, 95%) and feet (n = 28/38, 74%). Pruritus was absent in all patients with probable AHEI and described for 6/21 with doubtful AHEI (29%). AHEI was the original diagnosis in only 24 patients (n = 24/40, 60%). The major differential diagnoses were purpura fulminans and urticaria multiforme. Conclusion: AHEI, which the diagnosis is made on clinical findings, is often misdiagnosed. Purpuric lesions localized on the face/ears, arms/forearms, and thighs/legs with edema of the hands without pruritus in a young child with a good overall condition are highly suggestive of AHEI. What is Known: â¢Acute hemorrhagic edema of infancy (AHEI) is a cutaneous leukocytoclastic vasculitis affecting children under 3 years old. â¢Appropriate diagnosis is important to distinguish this benign disease from more serious diseases to avoid investigations and treatments, iatrogenic harm and unnecessary follow-up. What is New: â¢AHEI is an uncommon disorder often misdiagnosed by pediatricians and dermatologists. â¢Purpuric lesions localized on the face/ears, arms/forearms, and thighs/legs with edema of the hands without pruritus in an infant with a good overall condition are highly suggestive of AHEI.
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BACKGROUND: Low-flow malformations (LFMs) are rare diseases with a significant impact on health-related quality of life (HRQoL), especially in children. No disease-specific questionnaire is available for children with LFMs. OBJECTIVE: To develop and validate a specific HRQoL questionnaire for children from 11 to 15 years old suffering from LFMs. METHODS: A preliminary questionnaire based on a verbatim from focus groups was created and sent to children from 11 to 15 years old suffering from LFMs, together with a dermatology-specific and a generic HRQoL questionnaire (cDLQI and EQ-5D-Y). RESULTS: A total of 75 from 201 included children responded to the questionnaires. The final version of the questionnaire (cLFM-QoL) included 15 questions and was not divisible into subscales. It demonstrated excellent internal consistency (cronbach 0.89), convergent validity and readability (SMOG 6.04). cLFM-QoL mean score (± SD) was 12.9/45 (8.03) for all grades of severity, for mild 8.22/45 (7.5), moderate 14.03/45 (8.35), severe 12.35/45 (6.59) or very severe patients 20.7/45 (3.39) (p 0.006). CONCLUSION: cLFM-QoL is a validated short and easy to use specific questionnaire with excellent psychometric capacities. It will be suitable for any children aged 11-15 with LFMs, in daily practice or clinical trials.
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Qualidade de Vida , Humanos , Criança , Adolescente , Inquéritos e Questionários , Psicometria , Grupos Focais , Reprodutibilidade dos TestesRESUMO
This work reports 30 cases of folliculitis decalvans (FD) in patients with dystrophic epidermolysis bullosa (DEB) among a cohort of 125 DEB patients seen between 2010 and 2021 in 2 French expert centers for the management of inherited epidermolysis bullosa. Such an association between two rare diseases cannot be fortuitous and implies a physiopathological link that we discuss in this paper. This association is a new significant fact to add to the reflexion on FD causes, suggesting that skin abnormality of DEB could act as a factor of a specific skin barrier alteration which could favor FD. Scarring alopecia with tufted folliculitis and pustules on inflamed skin at the vertex of a woman with dominant dystrophic epidermolysis bullosa.
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Epidermólise Bolhosa Distrófica , Epidermólise Bolhosa , Foliculite , Feminino , Humanos , Epidermólise Bolhosa Distrófica/complicações , Epidermólise Bolhosa Distrófica/patologia , Alopecia/etiologia , Alopecia/patologia , Pele/patologia , Foliculite/complicações , Epidermólise Bolhosa/patologiaRESUMO
BACKGROUND: Congenital nail matrix nevi (NMN) are difficult to diagnose because they feature clinical characteristics suggestive of adult subungual melanoma. Nail matrix biopsy is difficult to perform, especially in children. OBJECTIVE: To describe the initial clinical and dermatoscopic features of NMN appearing at birth (congenital) or after birth but before the age of 5 years (congenital-type). METHODS: We conducted a prospective, international, and consecutive data collection in 102 hospitals or private medical offices across 30 countries from 2009 to 2019. RESULTS: There were 69 congenital and 161 congenital-type NMNs. Congenital and congenital-type NMN predominantly displayed an irregular pattern of longitudinal microlines (n = 146, 64%), reminiscent of subungual melanoma in adults. The distal fibrillar ("brush-like") pattern, present in 63 patients (27.8%), was more frequently encountered in congenital NMN than in congenital-type NMN (P = .012). Moreover, congenital NMN more frequently displayed a periungual pigmentation (P = .029) and Hutchinson's sign (P = .027) than did congenital-type NMN. LIMITATIONS: Lack of systematic biopsy-proven diagnosis and heterogeneity of clinical and dermatoscopic photographs. CONCLUSION: Congenital and congenital-type NMN showed worrisome clinical and dermatoscopic features similar to those observed in adulthood subungual melanoma. The distal fibrillar ("brush-like") pattern is a suggestive feature of congenital and congenital-type NMN.
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Melanoma , Doenças da Unha , Nevo , Neoplasias Cutâneas , Adulto , Criança , Pré-Escolar , Dermoscopia , Diagnóstico Diferencial , Humanos , Recém-Nascido , Melanoma/diagnóstico por imagem , Melanoma/patologia , Doenças da Unha/diagnóstico por imagem , Doenças da Unha/patologia , Nevo/diagnóstico , Estudos Prospectivos , Neoplasias Cutâneas/diagnóstico por imagem , Neoplasias Cutâneas/patologiaRESUMO
BACKGROUND: Psoriasis is a chronic inflammatory skin disease that has a profound effect on health-related quality of life (HRQoL). Patient education programmes may help patients to gain life-long control over their chronic disease. OBJECTIVE: This multicentre randomised controlled study evaluated whether a standardised multidisciplinary education programme was beneficial to psoriasis patients. METHODS: Adults with moderate-to-severe psoriasis were randomly assigned (1:1) to an intervention group to receive an educational programme or to a control group to receive usual care. Randomization was stratified by previous treatment history. The primary outcome was HRQoL, assessed by scoring the Skindex-29 domains emotion, symptom, and functioning. Psoriasis severity was assessed using the psoriasis area severity index (PASI). Levels of perceived stress, patient knowledge about psoriasis, and patient satisfaction were also assessed. Follow-up evaluations were performed at 3, 6, and 12 months. RESULTS: A total 142 patients formed the intention-to-treat population: 70 in the control group and 72 in the intervention group. Skindex component scores and the PASI were significantly lower at 3, 6, and 12 months as compared to baseline in both groups, but no significant differences were found between the groups. Knowledge about psoriasis improved significantly during follow-up amongst patients from the intervention group compared to controls (68% of correct answers vs. 56%; p < 0.01). Patient satisfaction with psoriasis management and treatment was also better in the intervention group. CONCLUSIONS: The standardised education programme did not improve HRQoL and disease severity in psoriasis, but led to a significant improvement in patient knowledge about the disease and increased patient satisfaction.
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Educação de Pacientes como Assunto , Psoríase , Adulto , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Avaliação de Programas e Projetos de Saúde , Psoríase/psicologia , Psoríase/terapia , Qualidade de Vida , Índice de Gravidade de DoençaRESUMO
BACKGROUND/OBJECTIVES: We observed isolated cases of perialar intertrigo in children and teenagers that did not appear to correspond to any known clinical entity. The objective of this study was to describe the clinical features of this dermatosis and the clinical characteristics of the patients. METHODS: We conducted a prospective, multicenter cohort study in France from August 2017 to November 2019. All the patients under 18 years of age with chronic perinasal intertrigo were included. A standardized questionnaire detailing the clinical characteristics of the patients and the description of the intertrigo. If possible, a Wood's lamp examination of the intertrigo was done. RESULTS: Forty-one patients were included (25 boys and 16 girls, average age: 12.1 years). Intertrigo was bilateral in 38 patients (93%). The majority of patients had no symptoms (54%). Pruritus was present in 39% of cases. Orange red follicular fluorescence was present in the perialar region on Wood's light examination in 78% of cases with active fluorescence. The presumptive diagnoses suggested by the investigators were acne (24.4%), seborrheic dermatitis (19.5%), rosacea (9.8%), psoriasis (9.8%) and perioral dermatitis (7.3%). No diagnosis was proposed in 22% of the cases. CONCLUSIONS: We describe a previously undescribed clinical sign which is characterized by a chronic bilateral erythematous intertrigo located in the perialar region. It can be isolated or associated with various facial dermatoses.
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Intertrigo , Psoríase , Rosácea , Adolescente , Criança , Estudos de Coortes , Feminino , Humanos , Intertrigo/diagnóstico , Masculino , Estudos Prospectivos , Psoríase/diagnósticoRESUMO
Megalencephaly-CApillary malformation-Polymicrogyria (MCAP) syndrome results from somatic mosaic gain-of-function variants in PIK3CA. Main features are macrocephaly, somatic overgrowth, cutaneous vascular malformations, connective tissue dysplasia, neurodevelopmental delay, and brain anomalies. The objectives of this study were to describe the clinical and radiological features of MCAP, to suggest relevant clinical endpoints applicable in future trials of targeted drug therapy. Based on a French collaboration, we collected clinical features of 33 patients (21 females, 12 males, median age of 9.9 years) with MCAP carrying mosaic PIK3CA pathogenic variants. MRI images were reviewed for 21 patients. The main clinical features reported were macrocephaly at birth (20/31), postnatal macrocephaly (31/32), body/facial asymmetry (21/33), cutaneous capillary malformations (naevus flammeus 28/33, cutis marmorata 17/33). Intellectual disability was present in 15 patients. Among the MRI images reviewed, the neuroimaging findings were megalencephaly (20/21), thickening of corpus callosum (16/21), Chiari malformation (12/21), ventriculomegaly/hydrocephaly (10/21), cerebral asymmetry (6/21) and polymicrogyria (2/21). This study confirms the main known clinical features that defines MCAP syndrome. Taking into account the phenotypic heterogeneity in MCAP patients, in the context of emerging clinical trials, we suggest that patients should be evaluated based on the main neurocognitive expression on each patient.
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Anormalidades Múltiplas/diagnóstico por imagem , Anormalidades Múltiplas/fisiopatologia , Ensaios Clínicos como Assunto , Megalencefalia/diagnóstico por imagem , Megalencefalia/fisiopatologia , Neuroimagem , Dermatopatias Vasculares/diagnóstico por imagem , Dermatopatias Vasculares/fisiopatologia , Telangiectasia/congênito , Anormalidades Múltiplas/tratamento farmacológico , Adolescente , Adulto , Criança , Pré-Escolar , Classe I de Fosfatidilinositol 3-Quinases/genética , Estudos de Coortes , Feminino , Previsões , Humanos , Imageamento por Ressonância Magnética , Masculino , Megalencefalia/tratamento farmacológico , Dermatopatias Vasculares/tratamento farmacológico , Telangiectasia/diagnóstico por imagem , Telangiectasia/tratamento farmacológico , Telangiectasia/fisiopatologia , Adulto JovemRESUMO
We report 20 newborns who developed, at a median age of 7 days, large abdominal patches of radially arranged purplish telangiectasia in a bilateral and symmetrical pattern in relation to the midline, creating a "butterfly wing" pattern. Clinical examination was normal in 13 newborns, six newborns had abdominal distention, and one newborn had poor weight gain due to inadequate breastfeeding. Most lesions spontaneously resolved within 3 months and did not reoccur for 19 newborns. Transient abdominal telangiectasia of the newborn (TATN) appears to be a distinctive entity that has not been previously described.
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Abdome , Telangiectasia , Humanos , Recém-Nascido , Telangiectasia/diagnósticoRESUMO
Annular lipoatrophy of the ankle is a rare and unique acquired lipoatrophic panniculitis that mainly affects children. There is no consensus on treatment, and the long-term course is not well known. We present four new pediatric cases that contribute to the understanding of this rare disease.
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Lipodistrofia , Paniculite , Tornozelo , Atrofia/patologia , Criança , Humanos , Lipodistrofia/diagnóstico , Paniculite/patologia , Gordura Subcutânea/patologiaRESUMO
BACKGROUND: The diagnosis of PTEN hamartoma tumor syndrome (PHTS) is difficult in children because they usually do not meet diagnostic criteria. The objective of our study was to characterize lipoma as an early presentation of PHTS. METHODS: We performed a retrospective review of children with PHTS diagnosed in French academic hospitals from 2000 to 2019. We included patients presenting at least one lipoma and PTEN-related disorder confirmed genetically. RESULTS: Thirteen children were included (mean age 5.5 years [range 2.5-16]). All children had solitary (n = 5) or multiple (n = 8) lipomas, all located on the trunk. Clinical examination revealed macrocephaly in all patients. Genital lentiginosis was found in all patients in whom genitalia were examined (n = 6). CONCLUSIONS: In addition to the classical presentation of PHTS with neurological disorders and macrocephaly, some patients, especially the youngest ones, have an initial dermatologic presentation with multiple lipomas. Search for penile freckling and macrocephaly in these patients allows for the diagnosis of PHTS. Lipomatosis should be a major diagnostic criterion in children.
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Síndrome do Hamartoma Múltiplo , Lipoma , Lipomatose , Megalencefalia , Adolescente , Criança , Pré-Escolar , Síndrome do Hamartoma Múltiplo/diagnóstico , Síndrome do Hamartoma Múltiplo/genética , Humanos , Lipoma/diagnóstico , Lipoma/genética , Megalencefalia/diagnóstico , Megalencefalia/genética , PTEN Fosfo-Hidrolase/genética , Estudos RetrospectivosRESUMO
Methotrexate has demonstrated its efficiency for the treatment of juvenile localized scleroderma but some patients may be resistant. The aim of our study was to define the profile of such patients. We performed an observational retrospective multicenter study between 2007 and 2016 and included all children seen in the French Paediatric Dermatology and Rheumatology departments with active localized scleroderma treated by methotrexate for a minimum of 4 months. Metho-trexate efficacy was assessed clinically and/or by imaging between the fourth to twelfth months of treatment. A total of 57 patients were included. Metho-trexate dosage ranged from 7 to 15 mg/m2/week. Only 4 patients were resistant. No common features could be identified between these 4 patients. Children with localized scleroderma are rarely resistant to metho-trexate and we did not identify a clinical profile for those resistant patients.
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Fármacos Dermatológicos/uso terapêutico , Resistência a Medicamentos , Metotrexato/uso terapêutico , Esclerodermia Localizada/tratamento farmacológico , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Estudos RetrospectivosRESUMO
Patients with an inherited autosomal-dominant disorder, capillary malformation-arteriovenous malformation (CM-AVM), frequently have mutations in Ras P21 protein activator 1 (RASA1). The aims of this study were to determine the prevalence of germline RASA1 variants in a French multicentre national cohort of children, age range 2-12 years, with sporadic occurrence of capillary malformation (CM) of the legs, whatever the associated abnormalities, and to identify genotype-phenotype correlates. DNA was extracted from leukocytes in blood samples, purified and amplified, and all exons of the RASA1 gene were analysed. Among 113 children analysed, 7 had heterozygous variants (6.1%). Four different variants were identified; 2 were new. In children with RASA1 variants, CMs were more frequently bilateral and multifocal. In conclusion, RASA1 variants are rarely found in children with sporadic CM of lower limbs without CM-AVM syndrome. CMs in this study were heterogeneous, and no disease-causing relationship could be proven.
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Malformações Arteriovenosas/genética , Capilares/anormalidades , Extremidade Inferior/irrigação sanguínea , Polimorfismo Genético , Mancha Vinho do Porto/genética , Proteína p120 Ativadora de GTPase/genética , Fatores Etários , Malformações Arteriovenosas/diagnóstico , Criança , Pré-Escolar , Feminino , França , Estudos de Associação Genética , Predisposição Genética para Doença , Heterozigoto , Homozigoto , Humanos , Masculino , Fenótipo , Mancha Vinho do Porto/diagnóstico , Fatores de RiscoAssuntos
Dermatologia , Saúde Sexual , Venereologia , Adolescente , Humanos , Dermatologistas , Inquéritos e Questionários , Comportamento SexualRESUMO
Epidermolysis bullosa simplex is a group of inherited disorders with allelic and locus heterogeneity in which skin fragility and blistering within the skin occur. Mutations in KRT5 and KRT14 underlie the majority of reported cases. Mutations in KLHL24, a gene that encodes KLHL24 protein, have been reported recently to cause a generalized subtype of epidermolysis bullosa simplex, presumably by increasing the degradation of keratin 14. We describe a case of KLHL24-related epidermolysis bullosa simplex and highlight the burn-like pattern of scars.
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Epidermólise Bolhosa Simples/genética , Proteínas Repressoras/genética , Pré-Escolar , Cicatriz/etiologia , Análise Mutacional de DNA , Epidermólise Bolhosa Simples/complicações , Epidermólise Bolhosa Simples/diagnóstico , Imunofluorescência , Humanos , Mutação , Pele/patologiaRESUMO
PURPOSE: Postzygotic activating mutations of PIK3CA cause a wide range of mosaic disorders collectively referred to as PIK3CA-related overgrowth spectrum (PROS). We describe the diagnostic yield and characteristics of PIK3CA sequencing in PROS. METHODS: We performed ultradeep next-generation sequencing (NGS) of PIK3CA in various tissues from 162 patients referred to our clinical laboratory and assessed diagnostic yield by phenotype and tissue tested. RESULTS: We identified disease-causing mutations in 66.7% (108/162) of patients, with mutant allele levels as low as 1%. The diagnostic rate was higher (74%) in syndromic than in isolated cases (35.5%; P = 9.03 × 10-5). We identified 40 different mutations and found strong oncogenic mutations more frequently in patients without brain overgrowth (50.6%) than in those with brain overgrowth (15.2%; P = 0.00055). Mutant allele levels were higher in skin and overgrown tissues than in blood and buccal samples (P = 3.9 × 10-25), regardless of the phenotype. CONCLUSION: Our data demonstrate the value of ultradeep NGS for molecular diagnosis of PROS, highlight its substantial allelic heterogeneity, and confirm that optimal diagnosis requires fresh skin or surgical samples from affected regions. Our findings may be of value in guiding future recommendations for genetic testing in PROS and other mosaic conditions.Genet Med advance online publication 02 February 2017.