Midfacial Toddler Excoriation syndrome (MiTES): case series, diagnostic criteria and evidence for a pathogenic mechanism.

BACKGROUND: PRDM12 polyalanine tract expansions cause two different disorders; Midfacial Toddler Excoriation Syndrome (MiTES) - itch with normal pain sensation associated with homozygous 18 alanines (18A), and congenital insensitivity to pain (CIP) with normal itch with homozygous 19A. Knowledge of the phenotype, genotype, and disease mechanism of MiTES is incomplete. Why PRDM12 18A versus 19A can cause almost opposite phenotypes is unknown; no other poly-alanine or poly-glutamine tract expansion disease causes two such disparate phenotypes. METHODS: We assessed the genotype and phenotype of 9 new, 9 atypical, and 6 previously reported patients diagnosed with MiTES. Using cell lines with homozygous PRDM12 of 12A (normal), 18A (MiTES) and 19A (CIP) we examined PRDM12 aggregation and subcellular localisation by image separation confocal microscopy and sub-cellular fractionation western blotting. RESULTS: MiTES presents in the first year of life, and in all cases the condition regresses over the first decade leaving scarring. The MiTES phenotype is highly distinctive. Features overlapping with PRDM12-CIP are rarely found. The genotype-phenotype study of PRDM12 polyalanine tract shows that 7A -15A are normal; 16A -18A are associated with MiTES; 19A leads to CIP; and no clinically atypical MiTES cases had an expansion. PRDM12 aggregation and sub-cellular localisation differ significantly between 18A and normal 12A cell lines and between 18A and 19A cell lines. MiTES is a new protein aggregation disease. CONCLUSION: We provide diagnostic criteria for MiTES, and improved longitudinal data. MiTES and CIP are distinct phenotypes despite their genotypes varying by a single alanine in the PRDM12 polyalanine tract. We found clear distinctions between the cellular phenotypes of normal, MiTES and CIP cells.. We hypothesise that the developmental environment of the trigeminal ganglion is unique and critically sensitive to prenatal and postnatal levels of PRDM12.

Topical steroid withdrawal: a survey of UK dermatologists' attitudes.

The term topical steroid withdrawal (TSW) refers to a condition widely discussed on social media, but rarely mentioned in the medical literature. It typically involves a patient with chronic eczema who abruptly discontinues topical corticosteroids (TCS) believing they are ineffective and damaging. Symptoms include an acute eruption, worse than the previous eczema, of painful erythema followed by oozing, crusting, desquamation and sometimes prolonged systemic weakness. Patients self-diagnose and often avoid healthcare professionals who dismiss the diagnosis and persist in offering TCS, leaving them unsupported. We analysed 121 responses to a survey of UK dermatologists' attitudes to TSW. Views on aetiology included relapsed eczema, erythroderma and a social construct. A total of 88.4% (107/121) agreed that TSW needs better understanding and more research. Respondents earlier in their careers are more cautious than senior respondents about prescribing TCS long term because of TSW, suggesting a trend that might lead to better understanding, communication and management.

Do people with eczema and their carers understand topical steroid potency? Results of two surveys.

Topical corticosteroids (TCSs) are classified into four potencies: mild, moderate, potent and very potent. Confusion arises from the wide range of products available, none of which have the potency level printed on the tubes or packaging. An online survey of patients and carers of people with eczema showed that only 17% of 984 respondents knew how many potencies there are. In a second survey, 315 respondents provided 1520 assignments of the potency of commonly used TCSs: 55.5% were correct, 21% were underestimates and 23.5% overestimates. Some errors were extreme: 12 (8%) of those using a very potent TCS considered it mild while 9 (27%) using a mild TCS considered it potent or very potent. Other themes expressed in free-text comments included inadequate and conflicting advice about using TCSs and lack of warnings about long-term adverse effects, particularly topical steroid withdrawal. Ninety-five per cent of respondents wanted TCSs to be clearly labelled with potency.

Börjeson-Forssman-Lehmann syndrome: delineating the clinical and allelic spectrum in 14 new families.

Börjeson-Forssman-Lehmann syndrome (BFLS) is an X-linked intellectual disability syndrome caused by variants in the PHF6 gene. We ascertained 19 individuals from 15 families with likely pathogenic or pathogenic PHF6 variants (11 males and 8 females). One family had previously been reported. Six variants were novel. We analysed the clinical and genetic findings in our series and compared them with reported BFLS patients. Affected males had classic features of BFLS including intellectual disability, distinctive facies, large ears, gynaecomastia, hypogonadism and truncal obesity. Carrier female relatives of affected males were unaffected or had only mild symptoms. The phenotype of affected females with de novo variants overlapped with the males but included linear skin hyperpigmentation and a higher frequency of dental, retinal and cortical brain anomalies. Complications observed in our series included keloid scarring, digital fibromas, absent vaginal orifice, neuropathy, umbilical hernias, and talipes. Our analysis highlighted sex-specific differences in PHF6 variant types and locations. Affected males often have missense variants or small in-frame deletions while affected females tend to have truncating variants or large deletions/duplications. Missense variants were found in a minority of affected females and clustered in the highly constrained PHD2 domain of PHF6. We propose recommendations for the evaluation and management of BFLS patients. These results further delineate and extend the genetic and phenotypic spectrum of BFLS.

British Society for Paediatric and Adolescent Dermatology assessment and support of mental health in children and young people with skin conditions: a multidisciplinary expert consensus statement and recommendations.

BACKGROUND: Psychological and mental health difficulties are common in children and young people (CYP) living with skin conditions and can have a profound impact on wellbeing. There is limited guidance on how best to assess and support the mental health of this population, who are at risk of poor health outcomes. OBJECTIVES: To provide consensus-based recommendations on the assessment and monitoring of and support for mental health difficulties in CYP with skin conditions (affecting the skin, hair and nails); to address practical clinical implementation questions relating to consensus guidance; and to provide audit and research recommendations. METHODS: This set of recommendations was developed with reference to the AGREE II instrument. A systematic review and literature appraisal was carried out. A multidisciplinary consensus group was convened, with two virtual panel meetings held: an initial meeting to discuss the scope of the study, to review the current evidence and to identify areas for development; and a second meeting to agree on the content and wording of the recommendations. Recommendations were then circulated to stakeholders, following which amendments were made and agreed by email. RESULTS: The expert panel achieved consensus on 11 recommendations for healthcare workers managing CYP with skin conditions. A new patient-completed history-taking aid ('You and Your Skin') was developed and is being piloted. CONCLUSIONS: The recommendations focus on improved mental health assessments for CYP presenting with a skin condition, with clinical guidance and suggested screening measures included. Information on accessing psychological support for CYP, when required, is given, and recommendations for staff training in mental health and neurodiversity provided. Embedding a psychosocial approach within services treating CYP with skin disease should ensure that CYP with psychological needs are able to be identified, listened to, supported and treated. This is likely to improve health outcomes.

Clinical, genetic, epidemiologic, evolutionary, and functional delineation of TSPEAR-related autosomal recessive ectodermal dysplasia 14.

TSPEAR variants cause autosomal recessive ectodermal dysplasia (ARED) 14. The function of TSPEAR is unknown. The clinical features, the mutation spectrum, and the underlying mechanisms of ARED14 are poorly understood. Combining data from new and previously published individuals established that ARED14 is primarily characterized by dental anomalies such as conical tooth cusps and hypodontia, like those seen in individuals with WNT10A-related odontoonychodermal dysplasia. AlphaFold-predicted structure-based analysis showed that most of the pathogenic TSPEAR missense variants likely destabilize the ß-propeller of the protein. Analysis of 100000 Genomes Project (100KGP) data revealed multiple founder TSPEAR variants across different populations. Mutational and recombination clock analyses demonstrated that non-Finnish European founder variants likely originated around the end of the last ice age, a period of major climatic transition. Analysis of gnomAD data showed that the non-Finnish European population TSPEAR gene-carrier rate is ∼1/140, making it one of the commonest AREDs. Phylogenetic and AlphaFold structural analyses showed that TSPEAR is an ortholog of drosophila Closca, an extracellular matrix-dependent signaling regulator. We, therefore, hypothesized that TSPEAR could have a role in enamel knot, a structure that coordinates patterning of developing tooth cusps. Analysis of mouse single-cell RNA sequencing (scRNA-seq) data revealed highly restricted expression of Tspear in clusters representing enamel knots. A tspeara -/-;tspearb -/- double-knockout zebrafish model recapitulated the clinical features of ARED14 and fin regeneration abnormalities of wnt10a knockout fish, thus suggesting interaction between tspear and wnt10a. In summary, we provide insights into the role of TSPEAR in ectodermal development and the evolutionary history, epidemiology, mechanisms, and consequences of its loss of function variants.

Biallelic TUFT1 variants cause woolly hair, superficial skin fragility and desmosomal defects.

BACKGROUND: Desmosomes are complex cell junction structures that connect intermediate filaments providing strong cell-to-cell adhesion in tissues exposed to mechanical stress. OBJECTIVES: To identify causal variants in individuals with woolly hair and skin fragility of unknown genetic cause. METHODS: This research was conducted using whole-genome sequencing, whole-exome sequencing, clinical phenotyping, haplotype analysis, single-cell RNA sequencing data analysis, immunofluorescence microscopy and transmission electron microscopy. RESULTS: We identified homozygous predicted loss-of-function tuftelin-1 (TUFT1) variants in nine individuals, from three families, with woolly hair and skin fragility. One donor splice-site variant, c.60+1G>A, was present in two families, while a frameshift variant, p.Gln189Asnfs*49, was found in the third family. Haplotype analysis showed the c.60+1G>A substitution to be a founder variant in the Irish population that likely arose approximately 20 generations ago. Human and mouse single-cell RNA sequencing data showed TUFT1 expression to be enriched in the hair dermal sheath and keratinocytes. TUFT1 expression was highly correlated with genes encoding desmosomal components implicated in diseases with phenotypes that overlap with the cohort presented here. Immunofluorescence showed tuftelin-1 to be mainly localized to the peripheral cell membranes of keratinocytes in normal skin. Skin samples from individuals with TUFT1 variants showed markedly reduced immunoreactivity for tuftelin-1, with a loss of the keratinocyte cell membrane labelling. Light microscopy revealed keratinocyte adhesion, mild hyperkeratosis and areas of superficial peeling. Transmission electron microscopy showed panepidermal acantholysis with widening of intercellular spaces throughout the epidermis and desmosomal detachment through the inner plaques. CONCLUSIONS: Biallelic loss-of-function TUFT1 variants cause a new autosomal recessive skin/hair disorder characterized by woolly hair texture and early-onset skin fragility. Tuftelin-1 has a role in desmosomal integrity and function.

Achenbach syndrome: no need for skin biopsy.

As dermatologists with Achenbach syndrome, we argue against the need for skin biopsy to confirm the diagnosis in this benign condition.

Mutations in the ribosome biogenesis factor gene LTV1 are linked to LIPHAK syndrome, a novel poikiloderma-like disorder.

In the framework of the UK 100 000 Genomes Project, we investigated the genetic origin of a previously undescribed recessive dermatological condition, which we named LIPHAK (LTV1-associated Inflammatory Poikiloderma with Hair abnormalities and Acral Keratoses), in four affected individuals from two UK families of Pakistani and Indian origins, respectively. Our analysis showed that only one gene, LTV1, carried rare biallelic variants that were shared in all affected individuals, and specifically they bore the NM_032860.5:c.503A > G, p.(Asn168Ser) change, found homozygously in all of them. In addition, high-resolution homozygosity mapping revealed the presence of a small 652-kb stretch on chromosome 6, encompassing LTV1, that was haploidentical and common to all affected individuals. The c.503A > G variant was predicted by in silico tools to affect the correct splicing of LTV1's exon 5. Minigene-driven splicing assays in HEK293T cells and in a skin sample from one of the patients confirmed that this variant was indeed responsible for the creation of a new donor splice site, resulting in aberrant splicing and in a premature termination codon in exon 6 of this gene. LTV1 encodes one of the ribosome biogenesis factors that promote the assembly of the small (40S) ribosomal subunit. In yeast, defects in LTV1 alter the export of nascent ribosomal subunits to the cytoplasm; however, the role of this gene in human pathology is unknown to date. Our data suggest that LIPHAK could be a previously unrecognized ribosomopathy.

The epidemiology of epidermolysis bullosa in England and Wales: data from the national epidermolysis bullosa database.

BACKGROUND: The National Health Service (NHS) epidermolysis bullosa (EB) service, established in 2002, offers comprehensive, free care to all patients in England and Wales. OBJECTIVES: To quantify prevalence, incidence and mortality of EB in England and Wales. METHODS: Demographic data for patients in England and Wales were collected on a secure electronic database, prospectively from January 2002 to April 2021 and retrospectively for cases prior to 2002. Vital status was verified using central NHS data. RESULTS: By March 2021, 2594 individuals were registered, of whom 2361 were living, which yielded a prevalence of 34·8 per million of the population for all EB types [EB simplex (EBS) 17 per million, dystrophic EB (DEB) 10·7 per million, junctional EB (JEB) 1 per million and Kindler EB 0·3 per million]. We recorded 1200 babies with EB born since 2002. The average incidence per million live births for EBS, DEB, JEB and Kindler EB was 32·5, 26·1, 8·9 and 0·9, respectively (total incidence for all types of EB was 67·8 per million). Birth rates fell progressively over the 19-year period for JEB-severe (JEB-S) (r = -0·56) and recessive DEB-severe (r = -0·44) and also for milder types of EB. We observed longer survival in JEB-S over the 19-year period (r2 = 0·18) with a median survival of 12·7 months over the past 5 years. CONCLUSIONS: In this study, we provide the first accurate epidemiological data for EB in England and Wales. We believe the observed reduction in birth incidence of severe types of EB reflects an uptake of genetic counselling advice, whereas the reduction in milder types may be due to delayed presentation. A potential small trend towards longer survival of babies with JEB-S may reflect improved multidisciplinary care.

Lung Protection by Cathepsin C Inhibition: A New Hope for COVID-19 and ARDS?

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-Lefèvre 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.

Kosaki overgrowth syndrome: A novel pathogenic variant in PDGFRB and expansion of the phenotype including cerebrovascular complications.

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.