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.

Identifying the psychosocial predictors of ultraviolet exposure to the face in patients with xeroderma pigmentosum: a study of the behavioural factors affecting clinical outcomes in this genetic disease.

BACKGROUND: For patients with xeroderma pigmentosum (XP), the main means of preventing skin and eye cancers is extreme protection against ultraviolet radiation (UVR), particularly for the face. We have recently developed a methodology for objectively measuring photoprotection behaviour ('UVR dose to facial skin') and have found that the degree of photoprotection varies greatly between patients with XP. We have previously identified factors affecting photoprotection behaviour in XP using a subjective measure of photoprotection. Here, we have used this objective methodology to identify the factors which determine photoprotection behaviour in XP. METHODS: We studied 29 psychological, social, demographic and clinical variables in 36 patients with XP. We have previously objectively measured UVR protection (by measuring the dose of UVR reaching the skin of the face over a 3-week period) in these patients. Here, we use linear mixed-effects model analysis to identify the factors which lead to the differences in degree of photoprotection observed in these patients. RESULTS: Psychosocial factors accounted for as much of the interindividual variation in photoprotection behaviour (29%) as demographic and clinical factors (24%). Psychosocial factors significantly associated with worse UVR protection included: automaticity of the behaviours, and a group of beliefs and perceptions about XP and photoprotection known to associate with poor treatment adherence in other diseases. CONCLUSIONS: We have identified factors contributing to poor photoprotection in XP. Identifying these potentially reversible psychosocial features has enabled us to design an intervention to improve photoprotection in patients with XP, aiming to prevent skin and eye cancers in these patients.

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.

Tricyclic antidepressant-induced photosensitivity; A case report and systematic review.

BACKGROUND/PURPOSE: Tricyclic antidepressants (TCAs) are still widely used and are available to purchase without prescription in some countries. Awareness of adverse cutaneous drug reactions is essential. METHOD: We reported a case of photo-distributed hyperpigmentation due to imipramine and carried out a systematic search of the related articles using the search terms "tricyclic antidepressants" or "tricyclic antidepressive agents", and "hyperpigmentation" or "photosensitivity disorder". Fifty non-duplicate citations were identified of which 28 articles which were independently assessed in full. The review was registered in PROSPERO, CRD42018107338. RESULTS: The remaining 25 articles met our inclusion criteria. Photo-distributed hyperpigmentation tricyclic antidepressant-induced photosensitivity reactions (TIPs) was the most common presentation. In 21 cases, this presented as an asymptomatic discolouration of exposed sites. Imipramine (81%), amitriptyline (9.5%), desipramine hydrochloride (4.8%) and mirtazapine (4.8%) were reported to be the culprit drugs. Nineteen were female with a mean age at presentation of 55 years. Mean duration from commencing the culprit drug until the development of discolouration was 10.4 years. Mean daily dose was 222.7 mg for imipramine. Histology was characteristic with golden-brown or brownish granules deposited in dermis. Staining for Masson-Fontana and MEL-5 was positive in all cases. Phototesting had not been done in cases prior to ours (negative 3 months after discontinuation of imipramine). Three further reports of suspected TIP presented with non-specific and eczematous eruption. The two presentations were reported along with systemic problems (thrombocytopenia and hepatic injury). CONCLUSIONS: This systematic review highlights the characteristic features of exposed site hyperpigmentation of TCA-induced photosensitivity occurring after prolonged drug exposure in many cases.

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.

Facial photoprotection in xeroderma pigmentosum (XP) patients: Validation of a new self-reported questionnaire of adherence.

BACKGROUND/PURPOSE: Adherence to photoprotection is the only way to prevent skin cancers and eye disease in xeroderma pigmentosum (XP). No validated self-report questionnaire exists for assessing adherence to photoprotection practices in individuals with XP. We sought to validate a self-reported measure of adherence to face photoprotection in this population. METHODS: Sixty six XP patients recruited from the patient list of the XP specialist service in London, UK, completed a questionnaire of adherence to specific photoprotection behaviours. We measured objective ultraviolet radiation (UVR) exposure to the face continuously for 21 days with a wristworn UVR electronic dosimeter combined with a daily photoprotection diary. Reliability and convergent validity of the questionnaire were tested in relation to overall UVR exposure, UVR dose to the face, daily photoprotection activities, other self-reported photoprotection practices and clinical ratings of patient's protection. RESULTS: Internal consistency of the questionnaire was satisfactory. Questionnaire total scores were concordant with objective UVR exposure and UVR dose to the face. However, not all participants who reported good/excellent face photoprotection on the questionnaire recorded high levels of photoprotection in the daily diary. Correlations between the questionnaire and other practices and the clinical rating ranged from small to large in size. There was no correlation between the level of face photoprotection and self-reported avoidance of going outside. CONCLUSIONS: Our questionnaire was reliable and had good convergent validity with other indicators of photoprotection. This questionnaire could assist clinicians to detect low levels of adherence, and the methodology used to develop validated questionnaires for other photosensitive conditions.

Melanin distribution in human epidermis affords localized protection against DNA photodamage and concurs with skin cancer incidence difference in extreme phototypes.

Epidermal DNA damage, especially to the basal layer, is an established cause of keratinocyte cancers (KCs). Large differences in KC incidence (20- to 60-fold) between white and black populations are largely attributable to epidermal melanin photoprotection in the latter. The cyclobutane pyrimidine dimer (CPD) is the most mutagenic DNA photolesion; however, most studies suggest that melanin photoprotection against CPD is modest and cannot explain the considerable skin color-based differences in KC incidence. Along with melanin quantity, solar-simulated radiation-induced CPD assessed immediately postexposure in the overall epidermis and within 3 epidermal zones was compared in black West Africans and fair Europeans. Melanin in black skin protected against CPD by 8.0-fold in the overall epidermis and by 59.0-, 16.5-, and 5.0-fold in the basal, middle, and upper epidermis, respectively. Protection was related to the distribution of melanin, which was most concentrated in the basal layer of black skin. These results may explain, at least in part, the considerable skin color differences in KC incidence. These data suggest that a DNA protection factor of at least 60 is necessary in sunscreens to reduce white skin KC incidence to a level that is comparable with that of black skin.-Fajuyigbe, D., Lwin, S. M., Diffey, B. L., Baker, R., Tobin, D. J., Sarkany, R. P. E., Young, A. R. Melanin distribution in human epidermis affords localized protection against DNA photodamage and concurs with skin cancer incidence difference in extreme phototypes.

Deep phenotyping of 89 xeroderma pigmentosum patients reveals unexpected heterogeneity dependent on the precise molecular defect.

Xeroderma pigmentosum (XP) is a rare DNA repair disorder characterized by increased susceptibility to UV radiation (UVR)-induced skin pigmentation, skin cancers, ocular surface disease, and, in some patients, sunburn and neurological degeneration. Genetically, it is assigned to eight complementation groups (XP-A to -G and variant). For the last 5 y, the UK national multidisciplinary XP service has provided follow-up for 89 XP patients, representing most of the XP patients in the United Kingdom. Causative mutations, DNA repair levels, and more than 60 clinical variables relating to dermatology, ophthalmology, and neurology have been measured, using scoring systems to categorize disease severity. This deep phenotyping has revealed unanticipated heterogeneity of clinical features, between and within complementation groups. Skin cancer is most common in XP-C, XP-E, and XP-V patients, previously considered to be the milder groups based on cellular analyses. These patients have normal sunburn reactions and are therefore diagnosed later and are less likely to adhere to UVR protection. XP-C patients are specifically hypersensitive to ocular damage, and XP-F and XP-G patients appear to be much less susceptible to skin cancer than other XP groups. Within XP groups, different mutations confer susceptibility or resistance to neurological damage. Our findings on this large cohort of XP patients under long-term follow-up reveal that XP is more heterogeneous than has previously been appreciated. Our data now enable provision of personalized prognostic information and management advice for each XP patient, as well as providing new insights into the functions of the XP proteins.

Sub-optimal Application of a High SPF Sunscreen Prevents Epidermal DNA Damage in Vivo.

The cyclobutane pyrimidine dimer (CPD) is a potentially mutagenic DNA photolesion that is the basis of most skin cancers. There are no data on DNA protection by sunscreens under typical conditions of use. The study aim was to determine such protection, in phototypes I/II, with representative sunscreen-user application. A very high SPF formulation was applied at 0.75, 1.3 and 2.0 mg/cm2. Unprotected control skin was exposed to 4 standard erythema doses (SED) of solar simulated UVR, and sunscreen-treated sites to 30 SED. Holiday behaviour was also simulated by UVR exposure for 5 consecutive days. Control skin received 1 SED daily, and sunscreen-treated sites received 15 (all 3 application thicknesses) or 30 (2.0 mg/cm2) SED daily. CPD were assessed by quantitative HPLC-tandem mass spectrometry (HPLC-MS/MS) and semi-quantitative immunostaining. In comparison with unprotected control sites, sunscreen significantly (p ≤ 0.001-0.05) reduced DNA damage at 1.3 and 2.0 mg/cm2 in all cases. However, reduction with typical sunscreen use (0.75 mg/cm2) was non-significant, with the exception of HPLC-MS/MS data for the 5-day study (p <0.001). Overall, these results support sunscreen use as a strategy to reduce skin cancer, and demonstrate that public health messages must stress better sunscreen application to get maximal benefit.

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.

Successful serial plasmapheresis for solar urticaria, a case report and literature review.

BACKGROUND/PURPOSE: Amidst the emergence of new therapeutic options, traditional therapeutic plasmapheresis (TPE) used in diseases involving a toxic substance in the plasma, remains a viable alternative for cases of recalcitrant solar urticaria (SU). We emphasize the importance of documenting successful experience with repeated plasmapheresis to increase awareness amongst physicians and dermatologists regarding this effective treatment option. MATERIAL AND METHOD: We reported a case of recalcitrant SU that had not responded to a combination of H1-antihistamines, immunosuppressants, omalizumab and intravenous immunoglobulin. We introduced serial TPE, which involved two consecutive days of procedures for each course was introduced. We detailed the regimen and highlighted the clinical and objective benefits observed with multiple treatments. Additionally, we compared this to other plasmapheresis regimens and their treatment responses previously reported for solar urticaria. RESULTS: Our patient underwent serial TPE, totaling 42 procedures over five years. Following the last TPE session, phototesting showed a sustained prolongation of minimal urticating doses (MUDS), which exceeded the maximum tested doses across nearly all ultraviolet (UV) and visible light ranges, with the exception of the two short ultraviolet B (UVB) wavelengths. MUDs increased to 25 from 6 mj/cm2 at 307.5± 5nm, and to 500 from 15 mj/cm2 at 320 ± 10nm, before the initial TPE. In our review, we included five articles covering eight SU patients who received TPE. Of these, the five patients with positive intradermal tests responded particularly well immediately after treatment. However, the condition relapsed within two weeks in one patient and within two months in another. In contrast, the other three patients with negative intradermal tests, showed no significant benefits from the treatment. No serious side effects from TPE were reported amongst the patients. CONCLUSIONS: This review underscores the efficacy of serial plasmapheresis procedures in treating refractory cases of SU, high3lighting the robust results observed.

Skin cancer induction by the antimycotic drug voriconazole is caused by impaired DNA damage detection due to chromatin compaction.

Phototoxicity and skin cancer are severe adverse effects of the anti-fungal drug Voriconazole (VOR). These adverse effects resemble those seen in xeroderma pigmentosum (XP), caused by defective DNA nucleotide excision repair (NER), and we show that VOR decreases NER capacity. We show that VOR treatment does not perturb the expression of NER, or other DNA damage-related genes, but that VOR localizes to heterochromatin, in complexes containing histone acetyltransferase GCN5. Impairment of GCN5 binding to histone H3 reduced acetylation of H3, restricting damage-dependent chromatin unfolding, thereby reducing NER initiation. Restoration of H3 histone acetylation using histone deacetylase inhibitors (HDACi), rescued VOR-induced NER repression, thus offering a preventive therapeutic option. These findings underline the importance of DNA damage-dependent chromatin remodeling as an important prerequisite of functional DNA repair.