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Cathepsin C (CatC) is a cysteine dipeptidyl aminopeptidase that activates most of tissue-degrading elastase-related serine proteases. Thus, CatC appears as a potential therapeutic target to impair protease-driven tissue degradation in chronic inflammatory and autoimmune diseases. A depletion of proinflammatory elastase-related proteases in neutrophils is observed in patients with CatC deficiency (Papillon-Lefevre syndrome). To address and counterbalance unwanted effects of elastase-related proteases, chemical inhibitors of CatC are being evaluated in preclinical and clinical trials. Neutrophils may contribute to the diffuse alveolar inflammation seen in acute respiratory distress syndrome (ARDS) which is currently a growing challenge for intensive care units due to the outbreak of the COVID-19 pandemic. Elimination of elastase-related neutrophil proteases may reduce the progression of lung injury in these patients. Pharmacological CatC inhibition could be a potential therapeutic strategy to prevent the irreversible pulmonary failure threatening the life of COVID-19 patients.

Heterozygous activating variants in platelet-derived growth factor, beta (PDGFRB) are associated with phenotypes including Kosaki overgrowth syndrome (KOGS), Penttinen syndrome and infantile myofibromatosis (IM). Here, we present three new cases of KOGS, including a patient with a novel de novo variant c.1477A > T p.(Ser493Cys), and the oldest known individual age 53 years. The KOGS phenotype includes characteristic facial features, tall stature, scoliosis, hyperelastic thin skin, lipodystrophy, variable intellectual and neurological deterioration, and abnormalities on brain imaging. Long-term outcome is unknown. Our cases confirm the phenotypic spectrum includes progressive flexion contractures, camptodactyly, widely spaced teeth, and constriction rings. We also propose novel occasional features including craniosynostosis, ocular pterygia, anterior chamber cleavage syndrome, early osteoporosis, increased pigmentation, recurrent haematomas, predisposition to cellulitis, nail dystrophy, carpal tunnel syndrome, recurrent hypoglycaemia in infancy, joint dislocation, and splenomegaly. Importantly, we report fusiform aneurysm of the basilar artery in two patients. Complications include thrombosis and stroke in the oldest reported patient and fatal rupture at the age of 21 in the patient with the novel variant. We conclude that cerebrovascular complications are part of the phenotypic spectrum of KOGS and KOGS-like disorders and suggest vascular imaging is indicated in these patients.

Background Aplasia cutis congenita (ACC) is a rare, congenital disorder characterized by localized or widespread absence of skin at birth with heterogeneous clinical presentation. The classification proposed by Frieden in 1986 is widely used. Aim To establish whether, 34 years on, the Frieden classification still meets the needs of dermatologists. Methods We conducted a retrospective chart review of all patients with a diagnosis of ACC presenting over a 25-year period to a tertiary paediatric dermatology department. We compiled demographic data, clinical characteristics (e.g. number, location and morphology of the lesions), imaging and genetic results where available, and other associated abnormalities, and grouped them according to the Frieden classification. For Type 6 ACC (Bart syndrome) we reviewed neonatal photographs of all babies born with epidermolysis bullosa (EB) over 5 years. Results Excluding Type 6, there were 56 children with ACC. The scalp was involved in 82.1%, and Type 1 was the commonest type. Over 5 years, 13 of 108 neonates (12%) with EB were born with the appearance of Type 6 ACC. Two children did not fit Frieden's original classification and one had a previously undescribed association of ACC with cleft lip/palate-ectodermal dysplasia 1 syndrome. Conclusion We conclude that the Frieden classification remains valid with some modifications. Type 3 ACC probably represents a mosaic RASopathy syndrome, while Type 7 could cover nongenetic ACC attributable to trauma. Type 8 should be subdivided into two subgroups: teratogenic and infective. Type 9 covers at least four subgroups. The classification will continue to evolve as new genes and pathomechanisms emerge.

Background: Several new genes and clinical subtypes have been identified since the publication in 2014 of the report of the last International Consensus Meeting on Epidermolysis Bullosa (EB). Objectives: We sought to reclassify disorders with skin fragility, with a focus on EB, based on new clinical and molecular data. Methods: This was a consensus expert review. Results: In this latest consensus report, we introduce the concept of genetic disorders with skin fragility, of which classical EB represents the prototype. Other disorders with skin fragility, where blisters are a minor part of the clinical picture or are not seen because skin cleavage is very superficial, are classified as separate categories. These include peeling skin disorders, erosive disorders, hyperkeratotic disorders, and connective tissue disorders with skin fragility. Because of the common manifestation of skin fragility, these ‘EB-related’ disorders should be considered under the EB umbrella in terms of medical and socioeconomic provision of care. Conclusions: The proposed classification scheme should be of value both to clinicians and researchers, emphasizing both clinical and genetic features of EB. What is already known about this topic?. Epidermolysis bullosa (EB) is a group of genetic disorders with skin blistering. The last updated recommendations on diagnosis and classification were published in 2014. What does this study add?. We introduce the concept of genetic disorders with skin fragility, of which classical EB represents the prototype. Clinical and genetic aspects, genotype–phenotype correlations, disease-modifying factors and natural history of EB are reviewed. Other disorders with skin fragility, e.g. peeling skin disorders, erosive disorders, hyperkeratotic disorders, and connective tissue disorders with skin fragility are classified as separate categories; these ‘EB-related’ disorders should be considered under the EB umbrella in terms of medical and socioeconomic provision of care. Linked Comment: Pope. Br J Dermatol 2020; 183:603.

Child abuse is a broad term which describes various forms of maltreatment and neglect in children and is recognized increasingly. Physical abuse presents to dermatologists as well as pediatricians because the skin is so readily accessible for harm. Doctors unfamiliar with the wide range of skin disorders that simulate child abuse may mistakenly diagnose child abuse or “fabricated or induced illness by carers” (Munchausen by proxy), with traumatic consequences for the family. Mimics of child abuse include various cultural practices, birthmarks, bleeding disorders, bacterial infections, bullous diseases, and hereditary conditions. Dermatitis artefacta and self-harm must also be considered. Observation of the skin lesions and their evolution during hospitalization may provide the correct answer, but knowledge of the morphology and presentation of various skin disorders is crucial to avoid incorrect diagnosis of child abuse. This article describes some of the less well-known mimics of child abuse. It is essential that dermatologists support pediatricians in managing conditions that appear unusual and possibly artifactual.

Cutaneous lymphadenoma is an uncommon benign neoplasm often considered to be an adamantinoid variant of trichoblastoma. Lesions present in both sexes, between 14 and 87 years of age, and are mainly located on the head and neck. Cases in children are rare and there is only 1 previous case of a congenital lymphadenoma. An 8-year-old Asian girl presented with a congenital lesion on her forehead comprising 4 pink papules, the largest 5 mm in diameter. Microscopy revealed a well-circumscribed tumor within the dermis and subcutis comprising well-demarcated epithelial lobules of basaloid and clear cells with subtle peripheral palisading, growing in a collagenous stroma but lacking retraction artefact. A relatively dense accompanying predominantly lymphocytic inflammatory cell infiltrate including both T-cells (CD3+) and B-cells (CD20+) permeated the nodules and spilled into the stroma. CD68+ histiocytes and CD1a+ Langerhans cells were moderately numerous. This is the second case of congenital lymphadenoma which-in spite of its rarity in childhood-widens the diagnostic possibilities of cutaneous lymphoepithelial tumors in children.

SummaryBackground Accurately diagnosing the subtype of epidermolysis bullosa (EB) is critical for management and genetic counselling. Modern laboratory techniques are largely inaccessible in developing countries, where the diagnosis remains clinical and often inaccurate. Objectives To develop a simple clinical diagnostic tool to aid in the diagnosis and subtyping of EB. Methods We developed a matrix indicating presence or absence of a set of distinctive clinical features (as rows) for the nine most prevalent EB subtypes (as columns). To test an individual patient, presence or absence of these features was compared with the findings expected in each of the nine subtypes to see which corresponded best. If two or more diagnoses scored equally, the diagnosis with the greatest number of specific features was selected. The matrix was tested using findings from 74 genetically characterized patients with EB aged > 6 months by an investigator blinded to molecular diagnosis. For concordance, matrix diagnoses were compared with molecular diagnoses. Results Overall, concordance between the matrix and molecular diagnoses for the four major types of EB was 91·9%, with a kappa coefficient of 0·88 [95% confidence interval (CI) 0·81–0·95; P < 0·001]. The matrix achieved a 75·7% agreement in classifying EB into its nine subtypes, with a kappa coefficient of 0·73 (95% CI 0·69–0·77; P < 0·001). Conclusions The matrix appears to be simple, valid and useful in predicting the type and subtype of EB. An electronic version will facilitate further testing.

BACKGROUND Recessive forms of congenital ichthyosis encompass a group of rare inherited disorders of keratinization leading to dry, scaly skin. So far, 13 genes have been implicated, but there is a paucity of data on genotype-phenotype correlation in some populations. OBJECTIVES We compiled an English cohort of 146 individuals with recessive ichthyosis and assessed genotype-phenotype correlation. METHODS Deep phenotyping was undertaken by history-taking and clinical examination. DNA was screened for mutations using a next-generation sequencing ichthyosis gene panel and Sanger sequencing. RESULTS Cases were recruited from 13 National Health Service sites in England, with 65% of patients aged < 16 years at enrolment. Pathogenic biallelic mutations were found in 83% of cases, with the candidate gene spread as follows: TGM1 29%, NIPAL4 12%, ABCA12 12%, ALOX12B 9%, ALOXE3 7%, SLC27A4 5%, CERS3 3%, CYP4F22 3%, PNPLA1 2%, SDR9C7 1%. Clinically, a new sign, an anteriorly overfolded ear at birth, was noted in 43% of patients with ALOX12B mutations. The need for intensive care stay (P = 0·004), and hand deformities (P < 0·001), were associated with ABCA12 mutations. Self-improving collodion ichthyosis occurred in 8% of the cases (mostly TGM1 and ALOX12B mutations) but could not be predicted precisely from neonatal phenotype or genotype. CONCLUSIONS These data refine genotype-phenotype correlation for recessive forms of ichthyosis in England, demonstrating the spectrum of disease features and comorbidities, as well as the gene pathologies therein. Collectively, the data from these patients provide a valuable resource for further clinical assessment, improving clinical care and the possibility of future stratified management. What's already known about this topic? Recessive forms of ichthyosis are rare but often difficult to diagnose. Mutations in 13 genes are known to cause recessive forms of ichthyosis: ABCA12, ALOX12B, ALOXE3, CERS3, CYP4F22, LIPN, NIPAL4, PNPLA1, SDR9C7, SLC27A4, SULT2B1, ST14 and TGM1. Some phenotypic features may associate with certain gene mutations, but paradigms for genotype-phenotype correlation need refining. What does this study add? The genotypic spectrum of recessive ichthyosis in England (based on 146 cases) comprises TGM1 (29%), NIPAL4 (12%), ABCA12 (12%), ALOX12B (9%), ALOXE3 (7%), SLC27A4 (5%), CERS3 (3%), CYP4F22 (3%), PNPLA1 (2%) and SDR9C7 (1%). New or particular phenotypic clues were defined for mutations in ALOX12B, ABCA12, CYP4F22, NIPAL4, SDR9C7 and TGM1, either in neonates or in later life, which allow for greater diagnostic precision. In around 17% of cases, the molecular basis of recessive ichthyosis remains unknown.

Happle-Tinschert syndrome (HTS) and Curry-Jones syndrome (CJS; OMIM 601707) are rare, sporadic, multisystem disorders characterized by hypo- and hyperpigmented skin patches following Blaschko's lines, plus acral skeletal and other abnormalities. The blaschkoid pattern implies mosaicism, and indeed CJS was found in 2016 to be caused by a recurrent postzygotic mutation in a gene of the hedgehog signalling pathway, namely SMO, c.1234C>T, p.Leu412Phe. More recently the original case of HTS was found to carry the same somatic mutation. Despite this genetic and phenotypic overlap, two significant differences remained between the two syndromes. The histological hallmark of HTS, basaloid follicular hamartomas, is not a feature of CJS. Meanwhile, the severe gastrointestinal manifestations regularly reported in CJS had not been described in HTS. We report a patient whose phenotype was entirely consistent with HTS apart from intractable constipation, and a second patient with classic features of CJS plus early-onset medulloblastoma, a feature of basal cell naevus syndrome (BCNS). Both had the same recurrent SMO mutation. This prompted a literature review that revealed a case with the same somatic mutation, with basaloid follicular hamartomas and other features of both CJS and BCNS. Segmental BCNS can also be caused by a somatic mutation in PTCH1. We thus demonstrate for the first time phenotypic and genetic overlap between HTS, CJS and segmental BCNS. All of these conditions are caused by somatic mutations in genes of the hedgehog signalling pathway and we therefore propose the unifying term 'mosaic hedgehog spectrum'. What's already known about this topic? Happle-Tinschert syndrome (HTS) and Curry-Jones syndrome (CJS) are rare mosaic multisystem disorders with linear skin lesions. CJS is characterized by severe constipation, which has not previously been reported in HTS. HTS is characterized by basaloid follicular hamartomas, which are not a recognized feature of CJS. The recurrent mosaic SMO mutation found in CJS was recently reported in a patient with HTS. What does this study add? We describe a patient with HTS and intractable constipation, and a case of CJS with medulloblastoma. Both patients had the same recurrent somatic SMO mutation also found in a case reported as segmental basal cell naevus syndrome. SMO functions in the hedgehog pathway, explaining phenotypic overlap between HTS, CJS and mosaic basal cell naevus syndrome. We propose the term 'mosaic hedgehog spectrum' for these overlapping conditions.

Chronic ulcerating lesions on the face are rarely seen in toddlers. Blistering disease, vasculitis, infections and self-mutilation due to neurometabolic disease can usually be excluded on clinical and histological grounds. In the absence of identifiable disease, such lesions are sometimes attributed to child abuse or fabricated illness. We describe three toddlers with chronic mid-face erosions, two from India and one from the UK. One had moderate developmental delay and one had had seizures. The lesions appeared to be self-inflicted, no underlying disease was identified and there was no suspicion of child abuse. Recognition of the same disease pattern in different continents implies a distinct pathological entity. The pattern closely resembles that seen in some patients with mutations in the pain-insensitivity genes PRDM12 and SCN11A. We suggest the term 'mid-face toddler excoriation syndrome' (MiTES) to acknowledge the existence of this condition, encourage further reports and help clarify the pathogenesis.

Summary The association of hypophosphataemic rickets with verrucous epidermal naevus (EN) and elevated fibroblast growth factor 23 levels is known as cutaneous–skeletal hypophosphataemia syndrome (CSHS), and can be caused by somatic activating mutations in RAS genes. We report a unique patient with CSHS associated with giant congenital melanocytic naevus (CMN), neurocutaneous melanosis and EN syndrome, manifesting as facial linear sebaceous naevus, developmental delay and ocular dermoids. An activating mutation Q61R in the NRAS gene was found in affected skin and ocular tissue but not blood, implying that the disparate manifestations are due to a multilineage activating mutation (mosaic RASopathy). We speculate on the apparently rare association of CSHS with CMN compared with EN. We also report the favourable outcome of this patient at the age of 8 years after extensive neonatal curettage of the giant CMN and use of vitamin D and phosphate supplementation.

Background Midface toddler excoriation syndrome (MiTES) is a condition recently reported in three unrelated children. Habitual scratching from the first year of life inflicted deep, chronic, scarring wounds around the nose and eyes. One child had a mild neurological deficit but there was no other evidence of insensitivity to pain. Bilateral distribution and localization to the midface distinguish MiTES from other causes of self-inflicted skin damage such as trigeminal trophic syndrome. An earlier study of five siblings from a consanguineous Irish family, with lesions corresponding to MiTES plus other sensory deficits, showed homozygous mutations in a gene for hereditary sensory and autonomic neuropathy type VIII (HSAN8), PRDM12. Objectives To study further cases of MiTES, including analysis of PRDM12. Methods We describe five further children, from four families, with facial lesions typical of MiTES, in whom mutation analysis of PRDM12 was carried out. Results Homozygous or compound heterozygous pathogenic expansions of the PRDM12 polyalanine tract were found in four of five affected individuals, in three families. Conclusions Our finding of autosomal recessive mutations in PRDM12 in four of five patients with MiTES extends the phenotypic spectrum of PRDM12 mutations, which usually cause HSAN8, characterized by mutilating self-inflicted wounds of the extremities, lips and tongue. By contrast, MiTES shows severe midfacial lesions with little if any evidence of generalized pain insensitivity. The condition is probably genetically heterogeneous, and other congenital insensitivity to pain and HSAN genes such as SCN11A may be implicated. This new understanding of the nature of MiTES, which can masquerade as factitious disease, will facilitate appropriate management.

BACKGROUND Our earlier study, published in 2004,found no skin cancer in a cohort of paediatric organ transplant recipients (POTRs) 5-16 years post-transplantation. We re-evaluated the same cohort 10 years later. OBJECTIVES To determine the prevalence of premalignant and malignant skin lesions and identify known risk factors associated with melanocytic naevi in a U.K. paediatric transplant population. METHODS Ninety-eight POTRs from the original 2004 study were invited to participate in this longitudinal follow-up study. History of sun exposure, demographics and transplantation details were collected using face-to-face interviews, questionnaires and case note reviews. Skin examination was performed for regional count of malignant lesions, benign and atypical naevi. RESULTS Of the 98 patients involved in the initial study, 45 POTRs (eight kidney, 37 liver), with a median follow-up of 19 years (range 15-26 years), agreed to participate. Neither skin cancer nor premalignant lesions were detected in these patients. When compared with the 2004 cohort, 41 patients in our current cohort had increased numbers of benign naevi (P

Setleis syndrome, focal facial dermal dysplasia type III (FFDD3, MIM #227260), is characterized by scar-like bitemporal lesions and other ocular and facial dysmorphic features. The syndrome results from recessive mutations in the TWIST2 gene, encoding a basic helix-loop-helix transcription factor or de novo genomic duplication or triplication, which include 1.3 Mb at 1p36.22p36.21, or other yet undefined lesions, emphasizing the syndrome's genetic heterogeneity. Recently, three patients were reported with 1p36.22p36.21 duplications/triplication that had the characteristic FFDD3 features and developmental delay or intellectual disabilities. Here, we describe a male with this microduplication, and the typical FFDD3 phenotype, but normal intelligence. Notably, his duplication was inherited from his father who did not have any FFDD3 manifestations, indicating lack of penetrance of the 1p36.22p36.21 microduplication. These findings emphasize phenotypic heterogeneity of the 1p36.22p36.21 copy number variant and the importance of screening the parents of patients with the 1p36.22p36.21 copy number variant to determine whether the duplication/triplication is de novo or inherited, for informed reproductive and genetic counseling.

Dermatitis artefacta (DA) is skin damage caused deliberately and secretly by the patient, and presented as skin disease, for covert secondary gain. In children DA must be distinguished from skin damage inflicted by others (abuse and fabricated or induced illness). Excluding the possibility of rare skin disease is difficult for paediatricians, who may feel unable to dismiss other dermatological diagnoses with authority. However there are usually positive diagnostic clues in the history, such as previous unexplained illness or psychosocial difficulties alleviated by the DA. Examination may reveal either a characteristic distribution or particular morphology of the lesions which will suggest the diagnosis. Most of the published cases are adults, in whom DA usually reflects significant psychological needs, or conscious deception for material gain. Children with DA have psychological needs too, but the spectrum of causes is different. At one end, normal children sometimes inflict lesions on themselves experimentally or in response to peer pressure, then find themselves caught up in a medical scenario. At the other, children trapped in an intolerable situation may resort to DA as a cry for help. Skill and sensitivity are required to provide an "exit strategy" or to divert a dermatological presentation to the appropriate agency such as clinical psychology or child protection.

Background Sporadic vascular malformations (VMs) are complex congenital anomalies of blood vessels that lead to stroke, life-threatening bleeds, disfigurement, overgrowth, and/or pain. Therapeutic options are severely limited and multi-disciplinary management remains challenging, particularly for high-flow arteriovenous malformations (AVM). Project To investigate the pathogenesis of 160 sporadic VMs in which known genetic causes had been excluded, sequencing of affected tissue DNA was undertaken using deep next generation sequencing with analysis optimised for detection of low mutant allele frequency. Results Mosaic activating variants in KRAS, NRAS, BRAF and MAP2K1 were identified, most commonly in AVM, both intracranial and extracranial. Transgenic zebrafish expressing BRAFV600E only in the vasculature recapitulated the human phenotype. Treatment of zebrafish with the BRAF inihibitor, vemurafinib, restored blood flow in AVM. Conclusions These findings reveal an important unifying cause of sporadic vascular malformations of different clinical types, and offer the potential of personalised medical treatment for affected individuals by repurposing of existing licensed cancer therapies.

Summary Dyskeratosis congenita (DC) is a clinically and genetically heterogeneous multisystem bone marrow failure disorder of telomere maintenance, which may present with dermatological features. The main cause of mortality is bone marrow failure, often developing in the second decade of life, although pulmonary disease and malignancies such as squamous cell carcinomas (SCCs) may also prove fatal. We report the case of a 28-year-old man with X-linked DC and confirmed DKC1 gene mutation. In addition to the classic triad of nail dystrophy, hyperpigmentation and oral leucoplakia, the patient had actinic keratosis (AK) and photodamaged skin, hitherto under-recognized features of this condition. Awareness of the clinical presentation of DC is important, as accurate clinical and molecular diagnosis affords patients and their families genetic counselling, cancer prevention and screening measures, and planning for complications such as bone marrow failure.

Three patients with CHKB deficient muscular dystrophy are described which broadens the previously described phenotype. Blood smear in one patient showed Jordans anomaly (vacuolated leukocytes). Gastrointestinal features occurred in two patients and there appeared to be acute deterioration with infection/general anaesthesia. Brain imaging showed no structural changes but brain magnetic resonance proton spectroscopy (MRS) demonstrated significant reduction in choline:N-acetyl aspartate and choline:creatine ratios in keeping with a general decrease in the amount of choline and phosphocholine-based substrate. Muscle pathology showed either myopathic or dystrophic features, uneven oxidative enzyme staining, COX deficient fibres and peripherally located large mitochondria. CHKB activity was reduced in all three patients and complex 1 activity was significantly reduced in one patient.

Diabetes mellitus is associated with a range of dermatologic presentations, including granuloma annulare and necrobiosis lipoidica diabeticorum. Granuloma annulare occurs earlier than necrobiosis lipoidica diabeticorum and the association with diabetes mellitus is much weaker. We describe two children with diabetes who both developed granuloma annulare and later, necrobiosis lipoidica diabeticorum. We postulate that the early onset and transient nature of granuloma annulare, compared with the later onset and persistence of necrobiosis lipoidica diabeticorum, might account for the different apparent rates of association with diabetes mellitus.

Recent high-profile cases have made paediatricians very aware of the serious implications of either missing or wrongly diagnosing non-accidental injury. Subdural fluid collections in non-mobile infants usually represent haemorrhage caused by non-accidental injury. We report a 6-month-old male who presented to the Accident and Emergency Department of Birmingham Heartlands Hospital with bilateral subdural fluid collections and skin ulcers resembling cigarette burns. Non-accidental injury was considered to be the most likely diagnosis. However, while under observation in hospital, the child's neurological condition deteriorated with progressive cerebral infarctions, and serial photographs of the skin lesions showed failure to heal. The revised diagnosis, confirmed histologically, was Degos disease, an extremely rare and often fatal occlusive vasculopathy. The child was treated palliatively and died 8 weeks after presentation. This report informs doctors of a new simulator of non-accidental injury to be considered in infants with otherwise unexplained subdural fluid collections.

Three children with pronounced livedo reticularis present since birth (cutis marmorata-telangiectasia congenita) have been followed to the ages of eight, 17 and 21 years. During childhood they developed frequent recurrent transient stroke-like hemipareses, affecting either side of the body, associated with ipsilateral pain, headache, visual symptoms, dysphasia, fits and confusion. Intellectual failure and, in one, progressive spasticity have followed. Attacks were more frequent in winter. Other problems have included abnormal peripheral vascular responses to temperature change, gastro-intestinal bleeding, glaucoma, local tissue hypertrophy and, in the two older patients, renal involvement with hypertension. Their condition represents a form of congenital vasculopathy. Anticonvulsants, anti-migraine agents, anti-platelet drugs and flunarizine have been ineffective. Nifedipine prevented further attacks in one patient and reduced attacks in another, but has not helped the third child. Adequate clothing and warmth may also be important.

Papillon-Lefevre syndrome (PLS) (OMIM: 245000) is a rare disease characterized by severe periodontitis and palmoplantar keratoderma. It is caused by mutations in both alleles of the cathepsin C (CatC) gene CTSC that completely abrogate the proteolytic activity of this cysteine proteinase. Most often, a genetic analysis to enable early and rapid diagnosis of PLS is unaffordable or unavailable. In this study, we tested the hypothesis that active CatC is constitutively excreted and can be easily traced in the urine of normal subjects. If this is true, determining its absence in the urine of patients would be an early, simple, reliable, low-cost and easy diagnostic technique. All 75 urine samples from healthy control subjects (aged 3 months to 80 years) contained proteolytically active CatC and its proform, as revealed by kinetic analysis and immunochemical detection. Of the urine samples of 31 patients with a PLS phenotype, 29 contained neither proteolytically active CatC nor the CatC antigen, so that the PLS diagnosis was confirmed. CatC was detected in the urine of the other two patients, and genetic analysis revealed no loss-of-function mutation in CTSC, indicating that they suffer from a PLS-like condition but not from PLS. Screening for the absence of urinary CatC activity soon after birth and early treatment before the onset of PLS manifestations will help to prevent aggressive periodontitis and loss of many teeth, and should considerably improve the quality of life of PLS patients.

Congenital erythropoietic porphyria (CEP, Günther's disease) has a very variable phenotype. In the more severely affected, bone marrow transplantation (BMT) is potentially curative, but is not without risks. We describe a 7-year-old girl with CEP characterized by severe photosensitivity but only mild anaemia, in whom the difficult decision to proceed with allogeneic BMT was made after discussion in a multidisciplinary team. She has shown successful engraftment, accompanied by biochemical and clinical resolution of her metabolic disease. She remains well 3 years later, the oldest patient with CEP receiving BMT to survive beyond 12 months. However, she has experienced significant morbidity including florid cutaneous graft-versus-host disease with postinflammatory hypopigmentation. Her case is important in highlighting the delay in diagnosis not uncommon in this condition and the complex decision-making process involved in proceeding with BMT.

Summary Background Solid organ transplant recipients are at increased risk of skin cancer. Melanoma is less common than nonmelanoma skin cancer (NMSC) although the relative proportion of melanoma among skin cancers has been shown to be higher in paediatric than adult recipients. Multiple melanocytic naevi and/or atypical naevi may be a risk factor for the development of melanoma. The relationship between naevus counts and phenotypic characteristics, disease-related variables and sun exposure has not been explored in paediatric transplant patients. Objectives To determine the prevalence of premalignant and malignant skin lesions and to identify known risk factors associated with benign and atypical melanocytic naevi in a U.K. paediatric transplant population. Methods Paediatric (≤ 19 years) renal and liver transplant patients, who were 5 or more years post-transplantation, were reviewed over 12 months. Lifetime history of sun exposure, episodes of sunburn, sunny holidays, sunscreen use, sun bed use, demographic and transplantation details were collected using interview, questionnaire and case note review. A skin examination was performed for regional counts of malignant lesions, benign and atypical naevi. Results Ninety-eight patients (82 liver, 13 renal, three multiorgan) with a median follow up of 9 years (range 5–16) were reviewed. Neither skin cancer nor premalignant lesions for NMSC were detected in this group. Eighty-five patients had benign naevi (median 6, range 1–57). Clinical risk factors for increased counts of benign naevi included increasing age (P = 0·03), more episodes of sunburn (P = 0·003) and prolonged treatment with ciclosporin (P = 0·009). The presence of atypical naevi in six patients was significantly associated with more episodes of sunburn (P = 0·006) and more transplants (P = 0·04). Other variables including phenotype, skin type, sun exposure, holidays abroad, residence abroad and total duration of immunosuppression did not correlate with benign or atypical naevus counts. Conclusions Skin cancer was not observed in paediatric solid organ transplant recipients who were 5–16 years post-transplantation. Both benign and atypical naevus counts were higher in children with frequent episodes of sunburn. As both naevi and sunburn are risk factors for melanoma, we should target fair-skinned transplant recipients with naevi for intensive sun avoidance education. A prospective, longitudinal follow-up study should determine the onset of skin cancer post-transplantation and the significance of benign and atypical naevus counts in this cohort.

Neurofibromatosis 1 (NF1) is a common neurocutaneous condition with an autosomal dominant pattern of inheritance. The complications are diverse and disease expression varies, even within families. Progress in molecular biology and neuroimaging and the development of mouse models have helped to elucidate the aetiology of NF1 and its clinical manifestations. Furthermore, these advances have raised the prospect of therapeutic intervention for this complex and distressing disease. Members of the United Kingdom Neurofibromatosis Association Clinical Advisory Board collaborated to produce a consensus statement on the current guidelines for diagnosis and management of NF1. The proposals are based on published clinical studies and on the pooled knowledge of experts in neurofibromatosis with experience of providing multidisciplinary clinical and molecular services for NF1 patients. The consensus statement discusses the diagnostic criteria, major differential diagnoses, clinical manifestations and the present strategies for monitoring and management of NF1 complications.

A 3-year-old boy with Proteus syndrome has a novel germline p.Y68D mutation of the PTEN gene inherited from his mother who has Cowden syndrome. In addition, DNA extracted from curettings of his widespread epidermal naevus shows loss of heterozygosity for this mutation. To our knowledge, this has not been described before.

Transgrediens et progrediens palmoplantar keratoderma, known as Greither's syndrome, was originally described in 1952 and is characterized by diffuse keratoderma of the palms and soles, extending to the back aspects (transgrediens) and involving the skin over the Achilles' tendon. Patchy hyperkeratosis also develops on the shins, knees, elbows, and sometimes on the skin flexures. We describe two unrelated families affected with Greither's syndrome, in which the same dominant missense mutation gave rise to the amino acid change N188S in K1. The previously reported cases of Greither's syndrome showed phenotypic variability suggestive of different underlying gene defects. Our findings suggest that at least some cases of Greither's syndrome are caused by keratin mutations.

Segmental neurofibromatosis type 1 (SNF1), characterized by the regionally limited distribution of neurofibromatosis type 1 (NF1) features, has been attributed to mosaicism for an NF1 gene mutation. The occurrence of classical NF1 in the offspring of a parent with SNF1 suggests that cutaneous mosaicism may be accompanied by gonadal mosaicism. We studied a girl with generalized NF1, and her mother who has SNF1. A recurrent nonsense mutation in exon 31 (R1947X) of the NF1 gene was identified in the lymphocyte DNA of the affected child by denaturing high-performance liquid chromatography and PCR/direct sequencing. DNA sequence analysis failed, however, to identify the R1947X mutation in peripheral lymphocytes, and in keratinocytes and fibroblasts cultured from affected and unaffected skin in the mother. DNA fragments containing exon 31 were then cloned from each cell line and these clones were screened using allele-specific PCR. The R1947X mutation was identified in 29 of 146 clones derived from keratinocytes from the affected region and in 12 of 136 clones derived from fibroblasts from the affected region, but in no clones derived from clinically unaffected tissues. These findings confirm that gonosomal mosaicism can occur in SNF1, with consequent important implications for genetic counselling.

Xeroderma pigmentosum (XP) and Cockayne syndrome (CS) are both rare autosomal recessive disorders with defects in DNA repair. They are usually distinct both clinically and genetically but in rare cases, patients exhibit the clinical characteristics of both diseases concurrently. We report two new phenotypically distinct cases of XP with additional features of CS (xeroderma pigmentosum and Cockayne syndrome crossover syndrome (XP/CS)) carrying an identical mutation (G47R) in the XPD gene within the N terminus of the protein. Both patients had clinical features of XP and CS but only one fulfilled most criteria for diagnosing CS. Unusually, patient 1 developed early skin cancer, in contrast to patient 2, who never developed any malignancies. Cells from both these patients have repair defects typical of xeroderma pigmentosum complementation group D (XPD) cells, but also had the phenotype of uncontrolled DNA breakage found specifically in XPD/CS cells and similarly reduced levels of TFIIH. Despite these similarities between our two patients, their clinical features are quite different and the clinical severity correlates with other cellular responses to ultraviolet irradiation.

Herlitz junctional epidermolysis bullosa (JEB) is an autosomal recessive mechanobullous disorder that results from loss-of-function mutations in the genes encoding the basement membrane component, laminin 5. Typically, there are frameshift, splice site or nonsense mutations on both alleles of either the LAMA3, LAMB3 or LAMC2 genes, with affected individuals inheriting one mutated allele from each parent. In this report, we describe a patient with Herlitz JEB in whom DNA analysis revealed homozygosity for the recurrent nonsense mutation R635X in LAMB3, located on chromosome 1q32.2. However, screening of parental DNA showed that although the patient's father was a heterozygous carrier of this mutation, the mother's DNA showed only wild-type sequence. Subsequent genotype analysis using 13 microsatellite markers spanning chromosome 1 revealed that the affected child was homozygous for the entire series of markers tested and that all of the alleles originated from the father. These results indicate that the Herlitz JEB phenotype in this patient is due to complete paternal isodisomy of chromosome 1 and reduction to homozygosity of the mutant LAMB3 gene locus. This is the fourth case of uniparental disomy to be described in Herlitz JEB, but it represents the first example of complete paternal isodisomy for chromosome 1 with a pathogenic mutation in the LAMB3 gene. These findings have important implications for mutation screening in JEB and for genetic counselling.

Slug is a zinc-finger neural crest transcription factor, encoded by the SLUG gene, which is critical for development of hematopoietic stem cells, germ cells, and melanoblasts in the mouse. In mouse, heterozygous and homozygous slug mutations result in anemia, infertility, white forehead blaze, and depigmentation of the ventral body, tail, and feet. This phenotype is very similar to the heterozygous W (KIT)-mutant mouse phenotype and to human piebaldism, which is characterized by a congenital depigmented patches and poliosis (white forelock). To investigate the possibility that some cases of human piebaldism might result from abnormalities of the human SLUG (SNAI2) gene, we carried out Southern blot analysis of the SLUG gene in 17 unrelated patients with piebaldism, who lack apparent KIT mutations. Three of these patients had evident heterozygous deletions of the SLUG gene encompassing the entire coding region. Real-time PCR confirmed the deletion in all cases. Fluoresence in situ hybridization (FISH) of genomic SLUG probes to metaphase chromosomes independently confirmed the deletion in one of the cases. These findings indicate that some cases of human piebaldism result from mutation of the SLUG gene on chromosome 8, and provide further strong evidence for the role of SLUG in the development of human melanocytes.

Background Familial progressive hyper- and hypopigmentation (FPHH) is an autosomal dominant skin condition presenting in childhood with generalized macular dyspigmentation, usually reported in patients of East Asian origin. It overlaps phenotypically with other dyschromatoses, but can now be distinguished by mutations in the KIT ligand gene (KITLG). Aim We report two unrelated white families with similar phenotypic presentations of FPHH developing in early childhood in several generations. Methods Sanger sequencing of the exons and flanking introns of KITLG was performed. Results This identified a new heterozygous missense mutation in each family (p.Thr34Asn and p.Val37Gly, respectively). Of the six affected individuals examined by us, two had cancer: a 62-year-old man in family 1 had developed two primary melanomas and a pharyngeal carcinoma, and a 42-year-old woman in family 2 had developed thyroid carcinoma. All had unusually sparse lateral eyebrows, a finding not previously reported in this condition. Conclusions We summarize the genetic spectrum of the dyschromatoses and discuss a possible increased risk of malignancy in FPHH.

Summary Introduction The role of pulsed dye lasers (PDL) in the treatment of childhood haemangiomas is controversial. Our aim was to compare treatment with PDL with a wait-and-see policy. Methods We did a prospective, randomised controlled trial in which we enrolled 121 infants aged 1–14 weeks with early haemangiomas. We assigned infants to PDL treatment (n=60) or observation (n=61), and followed them up to age 1 year. The main outcome measures assessed were proportion of lesions completely clear or with minimum residual signs, adverse reactions, including pigmentary disturbance and skin atrophy, complications such as ulceration and infection, proportion of children whose parents considered the haemangioma a problem, characteristics of the haemangioma, and an independent assessment of the haemangioma problem by a panel of five parents. Analysis was by intention to treat. Findings All infants completed the study. The number of children whose lesions showed complete clearance or minimum residual signs at 1 year was not significantly different in the PDL treated and observation groups (25, 42%, vs 27, 44%; p=0·92). However, PDL treated infants were more likely to have skin atrophy (17, 28%, vs 5, 8%; p=0·008) and hypopigmentation (27, 45%, vs 9, 15%; p=0·001). The frequency of complications was similar between groups. The only objective measure of resolution that improved with PDL treatment was haemangioma redness. The number of children whose parents considered the haemangioma to be a problem at 1 year did not differ much between groups (11 of 60, 18%, vs 9 of 61, 15%; p=0·78). The independent parent panel validated this result. Interpretation PDL treatment in uncomplicated haemangiomas is no better than a wait-and-see policy.

Summary Background Acral peeling skin syndrome (APSS) is a rare skin fragility disorder usually caused by mutations in the transglutaminase 5 gene (TGM5). Methods We investigated the mutation spectrum of APSS in the U.K., Germany and Poland. Results We identified 59 children with APSS from 52 families. The phenotype was readily recognizable, with some variation in severity both within and between families. Most cases had been misdiagnosed as the localized form of epidermolysis bullosa simplex (EBS-loc). Eighteen different TGM5 mutations were identified, 15 of which were novel. Eight mutations were unique to a single family, nine each occurred in two families, while the common p.Gly113Cys mutation linked to a second missense variant p.Thr109Met occurred in 47 of the 52 families and was homozygous in 28. Most patients were of nonconsanguineous white European origin. Conclusions We propose that APSS is under-reported and widely misdiagnosed as EBS-loc, with significant counselling implications as APSS is autosomal recessive while EBS-loc is dominant. We recommend screening for TGM5 mutations when EBS-loc is suspected but not confirmed by mutations in KRT5 or KRT14. Our report trebles the number of known TGM5 mutations. It provides further evidence that p.Gly113Cys is a founder mutation in the European population. This is consistent with the striking ethnic distribution of APSS in U.K., where the majority of patients are of nonconsanguineous white European origin, in contrast to the pattern of other recessive skin disorders.

Hypohidrotic ectodermal dysplasia (HED), a congenital disorder of teeth, hair, and eccrine sweat glands, is usually inherited as an X-linked recessive trait, although rarer autosomal dominant and recessive forms exist. We have studied males from four families with HED and immunodeficiency (HED-ID), in which the disorder segregates as an X-linked recessive trait. Affected males manifest dysgammaglobulinemia and, despite therapy, have significant morbidity and mortality from recurrent infections. Recently, mutations in IKK-gamma (NEMO) have been shown to cause familial incontinentia pigmenti (IP). Unlike HED-ID, IP affects females and, with few exceptions, causes male prenatal lethality. IKK-gamma is required for the activation of the transcription factor known as “nuclear factor kappa B” and plays an important role in T and B cell function. We hypothesize that “milder” mutations at this locus may cause HED-ID. In all four families, sequence analysis reveals exon 10 mutations affecting the carboxy-terminal end of the IKK-gamma protein, a domain believed to connect the IKK signalsome complex to upstream activators. The findings define a new X-linked recessive immunodeficiency syndrome, distinct from other types of HED and immunodeficiency syndromes. The data provide further evidence that the development of ectodermal appendages is mediated through a tumor necrosis factor/tumor necrosis factor receptor–like signaling pathway, with the IKK signalsome complex playing a significant role.

Epidermolysis bullosa simplex (EBS) is a blistering skin disease caused in most cases by mis-sense mutations in genes encoding the basal epidermal keratin (K) 5 and K14. The inheritance is usually autosomal dominant and the mutant keratin proteins appear to exert a dominant negative effect on the keratin intermediate filament cytoskeleton in basal keratinocytes. We report a child with a homozygous K14 mutation resulting in the complete absence of K14 protein in the epidermis; remarkably, he only had mild to moderate disease. Electron microscopy of a skin biopsy showed a marked reduction in numbers of keratin intermediate filaments in the basal keratinocytes. Immunofluorescence microscopy using monoclonal antibody LL001 against K14 showed no staining, suggesting a functional knockout of K14. Sequence analysis of genomic DNA revealed a homozygous mutation in codon 31 of K14 that resulted in a premature stop codon further downstream in exon 1. The child's mother, who is unaffected by the disease, is heterozygous for the mutation. The consanguineous father was unaffected and unavailable for testing. The resulting mRNA is predicted to encode a protein of 116 amino acids, of which the first 30 are identical to the normal K14 sequence, and the remaining 86 residues are mis-sense sequence. Four previously reported cases of autosomal recessive EBS with functional knockout of K14 were severely affected by blistering, in contrast to our patient in whom the predicted protein has only the first 30 amino acids of K14 and is therefore the closest to a true knockout of K14 protein yet identified.

Subcutaneous fat necrosis in a newborn is a rare, benign and self-limiting panniculitis. Hypercalcemia may develop and has been implicated as the cause of serious complications including seizures, nephrocalcinosis, and death. We report a case of subcutaneous fat necrosis in a newborn associated with asymptomatic and uncomplicated hypercalcemia, which resolved spontaneously.

Background The most serious complication of subcutaneous fat necrosis (SCFN), a rare condition of the newborn characterized by indurated purple nodules, is hypercalcaemia. However, the mechanism for this hypercalcaemia remains unclear. Objectives To determine whether the hypercalcaemia associated with SCFN involves expression of the vitamin D-activating enzyme 25-hydroxyvitamin D3-1α-hydroxylase (1α-hydroxylase) in affected tissue. Methods Skin biopsies from two male patients with SCFN and hypercalcaemia were taken. The histological specimens were assessed using a polyclonal antibody against 1α-hydroxylase. Results Histology in both cases showed strong expression of 1α-hydroxylase protein (brown staining) within the inflammatory infiltrate associated with SCFN. This was consistent with similar experiments in other granulomatous conditions. Conclusions Hypercalcaemia in SCFN appears to be due to abundant levels of 1α-hydroxylase in immune infiltrates associated with tissue lesions. This is consistent with previous observations of extrarenal 1α-hydroxylase in skin from other granulomatous conditions such as sarcoidosis and slack skin disease.

Lichen Planus (LP) is a common, very itchy papulosquamous disorder. Most reports of LP in children have come from the Indian subcontinent, suggesting that children of South Asian origin are more susceptible to developing LP. We conducted a retrospective, open, observational study of children with LP over a 10-year period, comparing the proportion of ethnicity in this group with the background ethnicity using UK census data from 2001. Of 26 children included in the study, 21 (80.8%) were from the Indian subcontinent, whereas the majority of the child population of Birmingham (0-17 years) was white (58%), with only 28% of the population being South Asian. Statistical analysis showed that the over-representation of South Asians in our series is significant (P < 0.001, 95% CI 56-91%). To our knowledge, this is the largest study on LP in children outside the Indian subcontinent.