Dupilumab in Chronic Actinic Dermatitis: a retrospective case series

We report a retrospective case series from two UK photobiology units of twelve patients with concomitant Atopic Dermatitis and Chronic Actinic Dermatitis treated with dupilumab as a systemic monotherapy. Whilst dupilumab is an effective therapy for moderate-severe AD, our results suggest that it may be less effective for the photosensitivity of CAD. In 11 of 12 patients with CAD, dupilumab was associated with improvement in dermatitis, but only half of patients noted improvement in photosensitivity.

A novel variant in the PTPN11 gene c.1277A>G p.(His426Arg) in a patient with Noonan Syndrome with Multiple Lentigines

Noonan Syndrome with Multiple Lentigines (NSML) is a rare autosomal dominant condition arising from gene variants involved in the RAS-MAPK pathway. The presence of multiple skin cancers is not widely reported in NSML. We report on a novel missense variant causing NSML in a patient with an unusual distribution of lentigines and multiple skin cancers. An increased awareness of the potential for malignant change of lentigines in NSML may encourage regular skin surveillance as a mainstay of multidisciplinary management, enabling early diagnosis and management of skin cancers in this group of patients.

A single-centre retrospective review of treatment responses and adverse events of thalidomide in patients with inflammatory skin disease

This retrospective review summarizes the effectiveness and safety concerns around using thalidomide in the treatment of inflammatory dermatoses.

Neurological disease in xeroderma pigmentosum: prospective cohort study of its features and progression

Xeroderma pigmentosum (XP) results from biallelic mutations in any of eight genes involved in DNA repair systems, thus defining eight different genotypes (XPA, XPB, XPC, XPD, XPE, XPF, XPG and XP variant or XPV). In addition to cutaneous and ophthalmological features, some patients present with XP neurological disease. It is unknown whether the different neurological signs and their progression differ among groups. Therefore, we aim to characterize the XP neurological disease and its evolution in the heterogeneous UK XP cohort. Patients with XP were followed in the UK National XP Service, from 2009 to 2021. Age of onset for different events was recorded. Cerebellar ataxia and additional neurological signs and symptoms were rated with the Scale for the Assessment and Rating of Ataxia (SARA), the Inventory of Non-Ataxia Signs (INAS) and the Activities of Daily Living questionnaire (ADL). Patients' mutations received scores based on their predicted effects. Data from available ancillary tests were collected. Ninety-three XP patients were recruited. Thirty-six (38.7%) reported neurological symptoms, especially in the XPA, XPD and XPG groups, with early-onset and late-onset forms, and typically appearing after cutaneous and ophthalmological symptoms. XPA, XPD and XPG patients showed higher SARA scores compared to XPC, XPE and XPV. SARA total scores significantly increased over time in XPD (0.91 points/year, 95% confidence interval: 0.61, 1.21) and XPA (0.63 points/year, 95% confidence interval: 0.38, 0.89). Hyporeflexia, hypopallesthaesia, upper motor neuron signs, chorea, dystonia, oculomotor signs and cognitive impairment were frequent findings in XPA, XPD and XPG. Cerebellar and global brain atrophy, axonal sensory and sensorimotor neuropathies, and sensorineural hearing loss were common findings in patients. Some XPC, XPE and XPV cases presented with abnormalities on examination and/or ancillary tests, suggesting underlying neurological involvement. More severe mutations were associated with a faster progression in SARA total score in XPA (0.40 points/year per 1-unit increase in severity score) and XPD (0.60 points/year per 1-unit increase), and in ADL total score in XPA (0.35 points/year per 1-unit increase). Symptomatic and asymptomatic forms of neurological disease are frequent in XP patients, and neurological symptoms can be an important cause of disability. Typically, the neurological disease will be preceded by cutaneous and ophthalmological features, and these should be actively searched in patients with idiopathic late-onset neurological syndromes. Scales assessing cerebellar function, especially walking and speech, and disability can show progression in some of the groups. Mutation severity can be used as a prognostic biomarker for stratification purposes in clinical trials.

Retrospective study of efficacy and adverse events of immune checkpoint inhibitors in 22 xeroderma pigmentosum patients with metastatic or unresectable cancers

Background

Xeroderma pigmentosum (XP), a rare disease with defects in DNA repair genes, has >1,000-fold increased risk of ultraviolet-induced skin cancers. Immune checkpoint inhibitors (ICIs) are used for treating cancers with large numbers of mutations but may also promote adverse events (AEs). Deficient DNA repair in XP patients may lead to increased numbers of mutations, leading to enhanced efficacy of cancer response or, alternatively, to increased AE in response to ICI. We sought to compare the efficacy and AE of ICI in XP patients with metastatic or unresectable cancers to that of ICI-treated patients in the general population.

Methods

In this retrospective study, we reviewed medical records of XP patients treated in the United States and in London (UK). We also reviewed published reports of ICI-treated XP patients and patients in the general population.

Results

Metastatic or unresectable cancers in all 22 (100%) XP patients showed regression or remission in response to ICI. The types and frequencies of AE in XP patients were similar to those reported among ICI-treated patients in the general population. However, two XP patients had concurrent additional cancers that did not respond to ICI, two XP patients had cancer recurrence or progression after initial response, and eight XP patients developed new skin cancers during or after ICI treatment.

Conclusion

In this retrospective study with small sample size, XP patients demonstrated positive responses to ICI and the treatment was well tolerated but some patients developed new skin cancers while being treated. ICIs can be considered in treating metastatic or unresectable cancers in XP patients.

A novel heterozygous missense variant in ribosomal protein L21 associated with familial hypotrichosis simplex

Hypotrichosis 12 (HYPT12) is an autosomal dominant, nonsyndromic hypotrichosis, caused by a pathogenic variant in the RPL21 gene encoding ribosomal protein L21, although only two pedigrees harbouring the amino acid substitution, p.Arg32Gln, have been reported previously. We present the case of a 44-year-old White British man with progressive hair loss since the age of 10 months, affecting his scalp, eyebrow, eyelashes and most of his body. Similar hair loss also affected several members of his family, with likely autosomal dominant inheritance. Using whole-exome sequencing, we identified a rare heterozygous missense variant (NM_000982.3:c.127A > G, NP_000973.2:p.Lys43Glu) in RPL21, and subsequent Sanger sequencing confirmed segregation of this variant in affected family members.

Genomic mutation landscape of skin cancers from DNA repair-deficient xeroderma pigmentosum patients

Xeroderma pigmentosum (XP) is a genetic disorder caused by mutations in genes of the Nucleotide Excision Repair (NER) pathway (groups A-G) or in Translesion Synthesis DNA polymerase η (V). XP is associated with an increased skin cancer risk, reaching, for some groups, several thousand-fold compared to the general population. Here, we analyze 38 skin cancer genomes from five XP groups. We find that the activity of NER determines heterogeneity of the mutation rates across skin cancer genomes and that transcription-coupled NER extends beyond the gene boundaries reducing the intergenic mutation rate. Mutational profile in XP-V tumors and experiments with POLH knockout cell line reveal the role of polymerase η in the error-free bypass of (i) rare TpG and TpA DNA lesions, (ii) 3' nucleotides in pyrimidine dimers, and (iii) TpT photodimers. Our study unravels the genetic basis of skin cancer risk in XP and provides insights into the mechanisms reducing UV-induced mutagenesis in the general population.

The Spectrum of MORC2-Related Disorders: A Potential Link to Cockayne Syndrome

BACKGROUND

Cockayne syndrome (CS) is a DNA repair disorder primarily associated with pathogenic variants in ERCC6 and ERCC8. As in other Mendelian disorders, there are a number of genetically unsolved CS cases.

METHODS

We ascertained five individuals with monoallelic pathogenic variants in MORC2, previously associated with three dominantly inherited phenotypes: an axonal form of Charcot-Marie-Tooth disease type 2Z; a syndrome of developmental delay, impaired growth, dysmorphic facies, and axonal neuropathy; and a rare form of spinal muscular atrophy.

RESULTS

One of these individuals bore a strong phenotypic resemblance to CS. We then identified monoallelic pathogenic MORC2 variants in three of five genetically unsolved individuals with a clinical diagnosis of CS. In total, we identified eight individuals with MORC2-related disorder, four of whom had clinical features strongly suggestive of CS.

CONCLUSIONS

Our findings indicate that some forms of MORC2-related disorder have phenotypic similarities to CS, including features of accelerated aging. Unlike classic DNA repair disorders, MORC2-related disorder does not appear to be associated with a defect in transcription-coupled nucleotide excision repair and follows a dominant pattern of inheritance with variants typically arising de novo. Such de novo pathogenic variants present particular challenges with regard to both initial gene discovery and diagnostic evaluations. MORC2 should be included in diagnostic genetic test panels targeting the evaluation of microcephaly and/or suspected DNA repair disorders. Future studies of MORC2 and its protein product, coupled with further phenotypic characterization, will help to optimize the diagnosis, understanding, and therapy of the associated disorders.

Local cutaneous refractoriness to sun exposure following omalizumab injections in solar urticaria

Images of solar urticaria in which localized skin areas remained refractory to sun exposure following omalizumab injections.

Pediatric Autoimmune Bullous Disease: A Literature Review and Update on Management

Pediatric autoimmune bullous disease is a rare group of blistering skin disorders in children that result from autoimmunity against intercellular and basement membrane antigens in the skin and mucous membranes. Most pediatric cases are treated with oral corticosteroids or longer-term immunosuppressants such as azathioprine or mycophenolate mofetil. Immunomodulating drugs such as rituximab are increasingly being considered as options for refractory disease.

Bilateral cochlear implantation in a young patient with xeroderma pigmentosum (XP-D) and progressive sensorineural hearing loss-How to do it?

Xeroderma pigmentosum (XP), a rare genetic skin condition, causes ultraviolet (UV)-induced neoplasms and possible neurological deficits including sensorineural hearingloss.

We present the first case in literature of bilateral cochlear implantation (CI) in a patient with XP-D with neurodegeneration. Multi-disciplinary team members (national XP team, dermatologist, anaesthetist, theatre team, biophysicists) were involved. UV exposure from equipment and areas where the 14-year-old patient would track was measured. Maximum possible surgery was performed under operating headlights to limit higher-UV microscope exposure. Its bulb light intensity was reduced to achieve safe UV level (0–10 μW/cm²). Skin was protected under surgical drapes. Challenges included drilling unpredicted hard thick bone under low-intensity light and requiring bulkier Nucleus®-7 processor due to unanticipated increased scarring. A delayed left facial weakness was resolved with steroids. He is undergoing hearing rehabilitation.

This highlights challenges of CI in XP. Its impact in preserving cognition and on neurodegeneration should also be observed.

100,000 Genomes Pilot on Rare-Disease Diagnosis in Health Care - Preliminary Report

BACKGROUND

The U.K. 100,000 Genomes Project is in the process of investigating the role of genome sequencing in patients with undiagnosed rare diseases after usual care and the alignment of this research with health care implementation in the U.K. National Health Service. Other parts of this project focus on patients with cancer and infection.

METHODS

We conducted a pilot study involving 4660 participants from 2183 families, among whom 161 disorders covering a broad spectrum of rare diseases were present. We collected data on clinical features with the use of Human Phenotype Ontology terms, undertook genome sequencing, applied automated variant prioritization on the basis of applied virtual gene panels and phenotypes, and identified novel pathogenic variants through research analysis.

RESULTS

Diagnostic yields varied among family structures and were highest in family trios (both parents and a proband) and families with larger pedigrees. Diagnostic yields were much higher for disorders likely to have a monogenic cause (35%) than for disorders likely to have a complex cause (11%). Diagnostic yields for intellectual disability, hearing disorders, and vision disorders ranged from 40 to 55%. We made genetic diagnoses in 25% of the probands. A total of 14% of the diagnoses were made by means of the combination of research and automated approaches, which was critical for cases in which we found etiologic noncoding, structural, and mitochondrial genome variants and coding variants poorly covered by exome sequencing. Cohortwide burden testing across 57,000 genomes enabled the discovery of three new disease genes and 19 new associations. Of the genetic diagnoses that we made, 25% had immediate ramifications for clinical decision making for the patients or their relatives.

CONCLUSIONS

Our pilot study of genome sequencing in a national health care system showed an increase in diagnostic yield across a range of rare diseases. (Funded by the National Institute for Health Research and others.).

Pathogenesis of solar urticaria: Classic perspectives and emerging concepts

Solar urticaria is a rare, immunologically mediated photodermatosis in which activation of cutaneous mast cells is triggered by specific wavelengths of solar electromagnetic radiation. This manifests clinically as the rapid development of cutaneous itch, erythema and wheal formation after several minutes of sun exposure. Disease mechanisms in solar urticaria remain incompletely elucidated and there have been few recent investigations of its pathobiology. Historic passive transfer experiments performed during the twentieth century provide support for a 'photoallergy' model of disease pathogenesis, wherein molecular alteration of a putative chromophore by solar electromagnetic radiation produces mast cell activation via an IgE-dependent mechanism. However, this model does not account for several observations made during passive transfer experiments nor does it explain a range of subsequent clinical and photobiological observations made in solar urticaria patients. Furthermore, increased understanding of the molecular dynamics underpinning cutaneous mast cell responses highlights the need to reformulate our understanding of solar urticaria pathogenesis in the context of this contemporary scientific landscape. In this review, we discuss the current understanding of solar urticaria pathogenesis and, by incorporating recent scientific and clinical observations, develop new hypotheses to drive future investigation into this intriguing disorder.

Metronidazole-Induced Hepatitis in a Teenager With Xeroderma Pigmentosum and Trichothiodystrophy Overlap

A teenage girl had the rare combined phenotype of xeroderma pigmentosum and trichothiodystrophy, resulting from mutations in the XPD (ERCC2) gene involved in nucleotide excision repair (NER). After treatment with antibiotics, including metronidazole for recurrent infections, she showed signs of acute and severe hepatotoxicity, which gradually resolved after withdrawal of the treatment. Cultured skin fibroblasts from the patient revealed cellular sensitivity to killing by metronidazole compared with cells from a range of other donors. This reveals that the metronidazole sensitivity was an intrinsic property of her cells. It is well recognized that patients with Cockayne syndrome, another NER disorder, are at high risk of metronidazole-induced hepatotoxicity, but this had not been reported in individuals with other NER disorders. We would urge extreme caution in the use of metronidazole in the management of individuals with the xeroderma pigmentosum and trichothiodystrophy overlap or trichothiodystrophy phenotypes.

Photodiagnostic services in the UK and Republic of Ireland: a British Photodermatology Group Workshop Report

BACKGROUND

Photodiagnostic investigations are essential for the accurate diagnosis of abnormal cutaneous photosensitivity and provide important information for the management of patients with photodermatoses (cutaneous photosensitivity disorders). Although photodiagnosis has been undertaken since the early 1970s, specialist services in the United Kingdom (UK) and Republic of Ireland are limited and there is no formal guidance on diagnostic approach. Indeed, there is a limited literature in this area of methodology and diagnostic practice.

OBJECTIVES

The primary objective was to undertake a British Photodermatology Group Workshop to review the role and activities of specialist centres in the UK and Republic of Ireland in order to ascertain whether there were consensus practices. Secondary objectives were to identify key priorities for service, training and research.

METHODS

An initial detailed survey review of current activities was undertaken prior to the Workshop and data from this survey were used to inform discussion at the Workshop, which was attended by key photodermatology experts from the UK and Republic of Ireland.

RESULTS/CONCLUSIONS

We have undertaken a detailed review of current Photodiagnostic Services in the UK and Republic of Ireland and report on our findings from the 12 centres and we have identified key areas of consensus practice. This is an important step in the process of standardising and optimising procedures and protocols and defining minimum clinical standards for photodiagnostic investigations, which are of such diagnostic importance in Dermatology.

Molecular analysis directs the prognosis, management and treatment of patients with xeroderma pigmentosum

Xeroderma pigmentosum (XP) is a well-studied disorder of (in most cases) nucleotide excision repair. The establishment in 2010 of a multidisciplinary XP clinic in the UK has enabled us to make a detailed analysis of genotype-phenotype relationships in XP patients and in several instances to make confident prognostic predictions. Splicing mutations in XPA and XPD and a specific amino acid change in XPD are associated with mild phenotypes, and individuals assigned to the XP-F group appear to have reduced pigmentation changes and a lower susceptibility to skin cancer than XPs in other groups. In an XP-C patient with advanced metastatic cancer arising from an angiosarcoma, molecular analysis of the tumour DNA suggested that immunotherapy, not normally recommended for angiosarcomas, might in this case be successful, and indeed the patient showed a dramatic recovery following immunotherapy treatment. These studies show that molecular analyses can improve the management, prognoses and therapy for individuals with XP.

Comparison of Narrowband UV-B With Psoralen-UV-A Phototherapy for Patients With Early-Stage Mycosis Fungoides: A Systematic Review and Meta-analysis

Importance

Phototherapy is one of the mainstays of treatment for early mycosis fungoides (MF). The most common modalities are psoralen-UV-A (PUVA) and narrowband UV-B (NBUVB).

Objective

To compare the efficacy and adverse effects of PUVA vs NBUVB in early-stage MF.

Data Sources

A systematic review was performed by searching Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Ovid Medline, PubMed, Cochrane Library, American College of Physicians ACP Journal Club, and Database of Abstracts of Review of Effectiveness from inception to March 30, 2018. UV A, PUVA, mycosis fungoides, Sézary syndrome, cutaneous T-cell lymphoma, UV B, and UVB were used as either key words or MeSH terms.

Study Selection

Studies of cohorts with histologically confirmed early-stage MF, defined as stages IA, IB, and IIA, that compared PUVA vs NBUVB, had at least 10 patients in each comparator group, and reported outcomes of response to therapy. Exclusion criteria were studies with patients with stage IIB or higher MF, pediatric patients, fewer than 10 in each comparator group, noncomparative studies, case reports, and abstract studies.

Data Extraction and Synthesis

The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline was followed. Data were pooled using a random-effects model with odds ratio (OR) as effect size.

Main Outcomes and Measures

Main outcomes were complete response rate, partial response rate, disease recurrence, and adverse effects, including erythema, nausea, pruritus, phototoxic effects, dyspepsia, and pain.

Results

Seven studies were included with a total of 778 patients (405 of 724 [55.9%] men; mean age, 52 years); 527 were treated with PUVA and 251 with NBUVB. Most of the included studies were of poor to moderate quality. Any response was found in 479 of the 527 (90.9%) patients treated with PUVA vs 220 of 251 (87.6%) treated with NBUVB (OR, 1.40; 95% CI, 0.84-2.34; P = .20). Complete response was found in 389 of 527 (73.8%) patients who received PUVA vs 156 of 251 (62.2%) who received NBUVB, which was statistically significant (OR, 1.68; 95% CI, 1.02-2.76; P = .04). Partial response was similar (90 of 501 [18.0%] vs 64 of 233 [27.5%]; OR, 0.58; 95% CI, 0.33-1.04; P = .07). No significant difference was found between PUVA and NBUVB in terms of adverse effects of erythema (38 of 527 [7.2%] vs 17 of 251 [6.7%]; P = .54), nausea (10 of 527 [1.9%] vs 3 of 251 [1.2%]; P = .72), pruritus (2 of 527 [0.4%] vs 4 of 251 [1.7%]; P = .26), phototoxic effects (7 of 527 [1.4%] vs 2 of 251 [0.9%]; P = .72), dyspepsia (6 of 527 [1.2%] vs 0 of 251 [0%]; P = .59), or pain (0 of 527 [0%] vs 2 of 251 [0.9%]; P = .50).

Conclusions and Relevance

The findings suggest that PUVA is a potential alternative to NBUVB in the management of early-stage MF. These findings have implications for clinicians involved in the management of early-stage MF.

Dramatic response of metastatic cutaneous angiosarcoma to an immune checkpoint inhibitor in a patient with xeroderma pigmentosum: whole-genome sequencing aids treatment decision in end-stage disease

"Mutational signatures" are patterns of mutations that report DNA damage and subsequent repair processes that have occurred. Whole-genome sequencing (WGS) can provide additional information to standard diagnostic techniques and can identify therapeutic targets. A 32-yr-old male with xeroderma pigmentosum developed metastatic angiosarcoma that was unresponsive to three lines of conventional sarcoma therapies. WGS was performed on his primary cancer revealing a hypermutated tumor, including clonal ultraviolet radiation-induced mutational patterns (Signature 7) and subclonal signatures of mutated DNA polymerase epsilon (POLE) (Signature 10). These signatures are associated with response to immune checkpoint blockade. Immunohistochemistry confirmed high PD-L1 expression in metastatic deposits. The anti-PD-1 monoclonal antibody pembrolizumab was commenced off-label given the POLE mutation and high mutational load. After four cycles, there was a significant reduction in his disease with almost complete resolution of the metastatic deposits. This case highlights the importance of WGS in the analysis, interpretation, and treatment of cancers. We anticipate that as WGS becomes integral to the cancer diagnostic pathway, treatments will be stratified to the individual based on their unique genomic and/or transcriptomic profile, enhancing classical approaches of histologically driven treatment decisions.

Hydroa vacciniforme-like lymphoproliferative disorder: an EBV disease with a low risk of systemic illness in whites

Patients with classic hydroa vacciniforme-like lymphoproliferative disorder (HVLPD) typically have high levels of Epstein-Barr virus (EBV) DNA in T cells and/or natural killer (NK) cells in blood and skin lesions induced by sun exposure that are infiltrated with EBV-infected lymphocytes. HVLPD is very rare in the United States and Europe but more common in Asia and South America. The disease can progress to a systemic form that may result in fatal lymphoma. We report our 11-year experience with 16 HVLPD patients from the United States and England and found that whites were less likely to develop systemic EBV disease (1/10) than nonwhites (5/6). All (10/10) of the white patients were generally in good health at last follow-up, while two-thirds (4/6) of the nonwhite patients required hematopoietic stem cell transplantation. Nonwhite patients had later age of onset of HVLPD than white patients (median age, 8 vs 5 years) and higher levels of EBV DNA (median, 1 515 000 vs 250 000 copies/ml) and more often had low numbers of NK cells (83% vs 50% of patients) and T-cell clones in the blood (83% vs 30% of patients). RNA-sequencing analysis of an HVLPD skin lesion in a white patient compared with his normal skin showed increased expression of interferon-γ and chemokines that attract T cells and NK cells. Thus, white patients with HVLPD were less likely to have systemic disease with EBV and had a much better prognosis than nonwhite patients. This trial was registered at www.clinicaltrials.gov as #NCT00369421 and #NCT00032513.

Xeroderma pigmentosum: overview of pharmacology and novel therapeutic strategies for neurological symptoms

Xeroderma pigmentosum (XP) encompasses a group of rare diseases characterized in most cases by malfunction of nucleotide excision repair (NER), which results in an increased sensitivity to UV radiation in affected individuals. Approximately 25-30% of XP patients present with neurological symptoms, such as sensorineural deafness, mental deterioration and ataxia. Although it is known that dysfunctional DNA repair is the primary pathogenesis in XP, growing evidence suggests that mitochondrial pathophysiology may also occur. This appears to be secondary to dysfunctional NER but may contribute to the neurodegenerative process in these patients. The available pharmacological treatments in XP mostly target the dermal manifestations of the disease. In the present review, we outline how current understanding of the pathophysiology of XP could be used to develop novel therapies to counteract the neurological symptoms. Moreover, the coexistence of cancer and neurodegeneration present in XP led us to focus on possible new avenues targeting mitochondrial pathophysiology. LINKED ARTICLES: This article is part of a themed section on Mitochondrial Pharmacology: Featured Mechanisms and Approaches for Therapy Translation. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.22/issuetoc.

Xeroderma pigmentosum is a definite cause of Huntington's disease-like syndrome

Xeroderma pigmentosum is characterized by cutaneous, ophthalmological, and neurological features. Although it is typical of childhood, late presentations can mimic different neurodegenerative conditions. We report two families presenting as Huntington's disease‐like syndromes. The first case (group G) presented with neuropsychiatric features, cognitive decline and chorea. Typical lentigines were only noticed after the neurological disease started. The second case (group B) presented adult‐onset chorea and neuropsychiatric symptoms after an aggressive ocular melanoma. Xeroderma pigmentosum can manifest as a Huntington's Disease‐like syndrome. Classic dermatological and oncological features have to be investigated in choreic patients with negative genetic tests for Huntington's disease‐like phenotypes.

Transcription restores DNA repair to heterochromatin, determining regional mutation rates in cancer genomes

Somatic mutations in cancer are more frequent in heterochromatic and late-replicating regions of the genome. We report that regional disparities in mutation density are virtually abolished within transcriptionally silent genomic regions of cutaneous squamous cell carcinomas (cSCCs) arising in an XPC(-/-) background. XPC(-/-) cells lack global genome nucleotide excision repair (GG-NER), thus establishing differential access of DNA repair machinery within chromatin-rich regions of the genome as the primary cause for the regional disparity. Strikingly, we find that increasing levels of transcription reduce mutation prevalence on both strands of gene bodies embedded within H3K9me3-dense regions, and only to those levels observed in H3K9me3-sparse regions, also in an XPC-dependent manner. Therefore, transcription appears to reduce mutation prevalence specifically by relieving the constraints imposed by chromatin structure on DNA repair. We model this relationship among transcription, chromatin state, and DNA repair, revealing a new, personalized determinant of cancer risk.

Patients with xeroderma pigmentosum complementation groups C, E and V do not have abnormal sunburn reactions

BACKGROUND

Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder of DNA repair. It is divided into eight complementation groups: XP-A to XP-G (classical XP) and XP variant (XP-V). Severe and prolonged sunburn reactions on minimal sun exposure have been considered a cardinal feature of classical XP. However, it has recently become clear that not all patients have abnormal sunburn reactions.

OBJECTIVES

To examine sunburn reactions in a cohort of patients with XP and correlate this to the complementation group.

METHODS

Sixty patients with XP attending the U.K. National XP Service from 2010 to 2012 were studied. Their history of burning after minimal sun exposure was assessed using a newly developed sunburn severity score. The age at which the first skin cancer was histologically diagnosed in each patient, and the presence of any neurological abnormality, was also recorded.

RESULTS

Sunburn severity scores were abnormally high in patients with XP-A, XP-D, XP-F and XP-G compared with non-XP controls. There was no significant difference in sunburn score of patients with XP-C, XP-E and XP-V compared with controls (P > 0·05). Patients with XP-C, XP-E and XP-V were more likely to have skin cancer diagnosed at an earlier age than those with severe sunburn on minimal sun exposure. In addition, patients with XP with severe sunburn had an increased frequency of neurological abnormalities.

CONCLUSIONS

Not all patients with XP have a history of severe and prolonged sunburn on minimal sun exposure. The normal sunburn response of patients with XP-C, XP-E and XP-V may relate to the preservation of transcription-coupled DNA repair in these groups. Those with a history of severe sunburn on minimal sun exposure developed their first skin cancer at an older age compared with patients with XP-C, XP-E and XP-V, but they had an increased frequency of neurological abnormalities. Physicians need to be aware that about half of all patients with XP will present without a history of abnormal sunburn.

Malfunction of nuclease ERCC1-XPF results in diverse clinical manifestations and causes Cockayne syndrome, xeroderma pigmentosum, and Fanconi anemia

Cockayne syndrome (CS) is a genetic disorder characterized by developmental abnormalities and photodermatosis resulting from the lack of transcription-coupled nucleotide excision repair, which is responsible for the removal of photodamage from actively transcribed genes. To date, all identified causative mutations for CS have been in the two known CS-associated genes, ERCC8 (CSA) and ERCC6 (CSB). For the rare combined xeroderma pigmentosum (XP) and CS phenotype, all identified mutations are in three of the XP-associated genes, ERCC3 (XPB), ERCC2 (XPD), and ERCC5 (XPG). In a previous report, we identified several CS cases who did not have mutations in any of these genes. In this paper, we describe three CS individuals deficient in ERCC1 or ERCC4 (XPF). Remarkably, one of these individuals with XP complementation group F (XP-F) had clinical features of three different DNA-repair disorders--CS, XP, and Fanconi anemia (FA). Our results, together with those from Bogliolo et al., who describe XPF alterations resulting in FA alone, indicate a multifunctional role for XPF.

Development and successful clinical application of preimplantation genetic haplotyping for Herlitz junctional epidermolysis bullosa

BACKGROUND

Herlitz junctional epidermolysis bullosa (HJEB) is a severe, life-threatening, autosomal recessive blistering skin disease for which no cure is currently available. Prenatal diagnosis for couples at risk is feasible through fetal skin biopsy or analysis of DNA extracted from chorionic villi, but these methods can be applied only after pregnancy has been established. An alternative approach, which involves the analysis of single cells from embryos prior to establishment of pregnancy, is preimplantation genetic diagnosis (PGD). Until now, its clinical uptake has been hindered by lengthy delays in establishing mutation-specific protocols, and by the small amount of template DNA that can be obtained from a single cell. A new method that addresses these problems, preimplantation genetic haplotyping (PGH), relies on whole genome amplification followed by haplotyping of multiple polymorphic markers using standard DNA-based polymerase chain reaction (PCR) assays.

OBJECTIVES

To design and validate a generic PGH assay for HJEB and to transfer this into clinical practice.

MATERIALS AND METHODS

We established a multiplex PCR-based PGH assay involving 16 markers within and flanking the LAMB3 gene (the most frequently mutated gene in HJEB). The assay was then validated in 10 families with at least one previously affected offspring. After licensing by the Human Fertilisation and Embryology Authority (HFEA), the new test was used for PGD in a couple at risk of HJEB.

RESULTS

The chromosome 1 LAMB3 markers within the assay were shown to be of sufficient heterogeneity to have widespread application for preimplantation testing of HJEB. In one couple that were heterozygous carriers of nonsense mutations in LAMB3, we used the new assay to identify unaffected embryos in a series of PGD cycles. Pregnancy was established in the third PGD cycle and a healthy, unaffected child was born. DNA analysis of cord blood confirmed the predicted single-cell mutation status of wild-type LAMB3 alleles.

CONCLUSIONS

PGH represents a major step forward in widening the scope and availability of preimplantation testing for serious mapped single-gene disorders. We have established a generic test that is suitable for the majority of couples at risk of HJEB.

Unusual molecular findings in Kindler syndrome

Kindler syndrome (KS) is a rare inherited skin disorder with blistering and poikiloderma as its main clinical features. It is caused by loss-of-function mutations in the C20orf42 (KIND1) gene which encodes kindlin-1, an actin cytoskeleton-focal contact-associated protein which is predominantly expressed in keratinocytes. We investigated the molecular basis of KS in a 16-year-old Indian boy who had additional clinical findings, including scleroatrophic changes of the hands and feet, pseudoainhum and early onset of squamous cell carcinoma on his foot. Immunostaining for kindlin-1 in the patient's skin was completely absent and sequencing of C20orf42 (KIND1) genomic DNA showed a homozygous splice-site mutation at the -6 position, IVS9-6T-->A. Amplification and sequencing of cDNA from the skin revealed aberrant splicing with either deletion of exon 10 or deletion of exons 9, 10 and 11, both of which involve loss of the pleckstrin homology domain of kindlin-1 that is thought to play a role in cytoskeletal attachment and integrin-mediated cell signalling. Pathogenic splice-site mutations at the -6 position are unusual and have rarely been reported for any genetic disorder. Collectively, these findings extend the spectrum of clinical and molecular abnormalities in this rare genodermatosis.

Patients with recessive dystrophic epidermolysis bullosa develop squamous-cell carcinoma regardless of type VII collagen expression

Recent data suggest that individuals with recessive dystrophic epidermolysis bullosa (RDEB) only develop squamous-cell carcinoma (SCC) in the presence of the NC1 domain of type VII collagen. This conclusion was based on experimental work in which cryosections of SCCs from 10 people with RDEB all showed positive type VII collagen immunostaining and observations in a murine model of SCC development in which tumors only occurred using keratinocytes from RDEB subjects that expressed detectable levels of the NC1 domain of the type VII collagen protein. To assess whether the clinical interpretation was valid in another cohort of RDEB patients, we examined expression of type VII collagen in 17 SCC tumors excised from 11 patients. Indirect immunofluorescent staining of SCC cryosections and Western blotting of cultured keratinocyte lysates identified two RDEB individuals who did not express detectable levels of type VII collagen. Mutation analysis revealed that these two patients harbor compound heterozygous nonsense mutations within the region of the COL7A1 gene encoding the NC1 domain. These data suggest that individuals with RDEB can develop SCC regardless of type VII collagen expression and that additional factors have a role in explaining the high incidence of tumors complicating this genodermatosis.