Evidence for persistent UV-induced DNA damage and altered DNA damage response in xeroderma pigmentosa patient corneas

Xeroderma pigmentosum (XP) is a rare genetic disorder characterized by injury to the ocular surface due to exposure to ultraviolet (UV) radiation. UV-induced damage in the cells leads to the formation of cyclobutane pyrimidine dimers (CPDs) and 6-4 pyrimidine-pyrimidone photoproducts that are repaired by the NER (Nucleotide Excision Repair) pathway. Mutations in the genes coding for NER proteins, as reported in XP patients, would lead to sub-optimal damage repair resulting in clinical signs varying from photo-keratitis to cancerous lesions on the ocular surface. Here, we aimed to provide evidence for the accumulation of DNA damage and activation of DNA repair pathway proteins in the corneal cells of patients with XP. Corneal buttons of patients who underwent penetrating keratoplasty were stained to quantify DNA damage and the presence of activated DNA damage response proteins (DDR) using specific antibodies. Positive staining for pH2A.X and thymidine dimers confirmed the presence of DNA damage in the corneal cells. Positive cells were found in both control corneas and XP samples however, unlike normal tissues, positive cells were found in all cell layers of XP samples indicating that these cells were sensitive to very low levels of UV. pH2A.X-positive cells were significantly more in XP corneas (p < 0.05) indicating the presence of double strand breaks in these tissues. A positive expression of phosphorylated-forms of DDR proteins was noted in XP corneas (unlike controls) such as ataxia telangiectasia mutated/Rad-3 related proteins (ATM/ATR), breast cancer-1 and checkpoint kinases-1 and -2. Nuclear localization of XPA was noted in XP samples which co-localized (calculated using Pearson's correlation) with pATM (0.9 ± 0.007) and pATR (0.6 ± 0.053). The increased presence of these in the nucleus confirms that unresolved DNA damage was accumulating in these cells thereby leading to prolonged activation of the damage response proteins. An increase in pp53 and TUNEL positive cells in the XP corneas indicated cell death likely driven by the p53 pathway. For comparison, cultured normal corneal epithelial cells were exposed to UV-radiation and stained for DDR proteins at 3, 6 and 24 h after irradiation to quantify the time taken by cells with intact DDR pathway to repair damage. These cells, when exposed to UV showed nuclear translocation of DDR proteins at 3 and 6 h which reduced significantly by 24 h confirming that the damaged DNA was being actively repaired leading to cell survival. The persistent presence of the DDR proteins in XP corneas indicates that damage is being actively recognized and DNA replication is stalled, thereby causing accumulation of damaged DNA leading to cell death, which would explain the cancer incidence and cell loss reported in these patients.

Physical, oral, and swallowing functions of three patients with type a xeroderma pigmentosum: a report of three cases

BACKGROUND

Xeroderma pigmentosum (XP) is an extremely rare and severe form of photosensitivity. It is classified into types A-G or V according to the gene responsible for the disease. The progression and severity of symptoms vary depending on the type. Although dysphagia caused by decreased swallowing function and dental malposition due to stenosis of the dentition in the facial and oral regions is common, it has not been reported in detail. We report three cases of type A XP, in which central and peripheral neurological symptoms appeared early on and progressed rapidly. We describe the oral function of these patients, focusing on the swallowing function and dentition malposition.

CASE PRESENTATION

Two males (27 and 25 years old) and one female (28 years old) presented with diverse neurological symptoms. We focused on the relationship between the changes in swallowing and oral functions and conditions due to decline in physical function. Some effects were observed by addressing the decline in swallowing and oral functions. In particular, a dental approach to manage the narrowing of the dentition, which was observed in all three patients, improved the swallowing and oral functions and maintained the current status of these functions.

CONCLUSIONS

In type A XP, early decline in oral and swallowing functions is caused by the early decline in physical function, and it is necessary to monitor the condition at an early stage.

TFIIH central activity in nucleotide excision repair to prevent disease

The heterodecameric transcription factor IIH (TFIIH) functions in multiple cellular processes, foremost in nucleotide excision repair (NER) and transcription initiation by RNA polymerase II. TFIIH is essential for life and hereditary mutations in TFIIH cause the devastating human syndromes xeroderma pigmentosum, Cockayne syndrome or trichothiodystrophy, or combinations of these. In NER, TFIIH binds to DNA after DNA damage is detected and, using its translocase and helicase subunits XPB and XPD, opens up the DNA and checks for the presence of DNA damage. This central activity leads to dual incision and removal of the DNA strand containing the damage, after which the resulting DNA gap is restored. In this review, we discuss new structural and mechanistic insights into the central function of TFIIH in NER. Moreover, we provide an elaborate overview of all currently known patients and diseases associated with inherited TFIIH mutations and describe how our understanding of TFIIH function in NER and transcription can explain the different disease features caused by TFIIH deficiency.

Successful treatment of non-melanoma skin cancer in three patients with Xeroderma Pigmentosum by modified ALA-PDT

Xeroderma pigmentosum(XP) is a rare autosomal recessive genodermatosis. Individuals with XP are characterized by severe skin sensitivity to sunlight, and more susceptible to the development of skin malignancies in sun-exposed regions. We report the experience of modified 5-aminolaevulinic acid photodynamic therapy (M-PDT) in the treatment of three children with XP. They all developed multiple freckle-like hyperpigmented papules and plaques on the face from an early age. Multiple cutaneous squamous cell carcinoma (cSCC) and actinic keratosis (AK) were developed in case 1 and case 2, and basal cell carcinoma (BCC) was observed in case 3. Sanger sequencing of targeted gene identified that case 1 and case 3 carried compound heterozygous mutations, and case 2 carried a homozygous mutation in the XPC gene. After multiple courses of M-PDT, the lesions were removed with mild adverse reactions, nearly painless and satisfactory safety.

Sarcomatoid Carcinoma of Orbit in a Patient With Xeroderma Pigmentosum

Spindle cell carcinoma (SpCC), also referred to as sarcomatoid carcinoma, makes up less than 3% of all head and neck squamous cell carcinomas (SCCs). It is an uncommon and unusual biphasic malignant tumor primarily affecting the upper aero-digestive tract. SpCC consists of spindled or pleomorphic tumor cells. Mostly, these tumors are seen in the fifth or sixth decades of life and are strongly associated with smoking and alcohol. We hereby report an infrequently encountered case of SpCC in a patient with xeroderma pigmentosum (XP), who was young, nonsmoker, and did not consume alcohol. The mass arose from the right orbit and involved the entire right face. The postoperative histopathological report showed SpCC. Surgical excision of the mass was performed. We aimed to add to the prevailing literature by reporting this case.

The nucleotide excision repair proteins through the lens of molecular dynamics simulations

Mutations that affect the proteins responsible for the nucleotide excision repair (NER) pathway can lead to diseases such as xeroderma pigmentosum, trichothiodystrophy, Cockayne syndrome, and Cerebro-oculo-facio-skeletal syndrome. Hence, understanding their molecular behavior is needed to elucidate these diseases' phenotypes and how the NER pathway is organized and coordinated. Molecular dynamics techniques enable the study of different protein conformations, adaptable to any research question, shedding light on the dynamics of biomolecules. However, as important as they are, molecular dynamics studies focused on DNA repair pathways are still becoming more widespread. Currently, there are no review articles compiling the advancements made in molecular dynamics approaches applied to NER and discussing: (i) how this technique is currently employed in the field of DNA repair, focusing on NER proteins; (ii) which technical setups are being employed, their strengths and limitations; (iii) which insights or information are they providing to understand the NER pathway or NER-associated proteins; (iv) which open questions would be suited for this technique to answer; and (v) where can we go from here. These questions become even more crucial considering the numerous 3D structures published regarding the NER pathway's proteins in recent years. In this work, we tackle each one of these questions, revising and critically discussing the results published in the context of the NER pathway.

Recurrent squamous cell carcinoma and a novel mutation in a patient with xeroderma pigmentosum: a case report

BACKGROUND

Xeroderma pigmentosum is an extremely serious genetic disorder defined by sensitivity to sunlight, resulting in sunburn and pigment changes. If patients are not completely protected from ultraviolet radiation, xeroderma pigmentosum is characterized by a greatly increased risk of sunlight-induced cutaneous neoplasms. There is no standard therapy for skin cancer of xeroderma pigmentosum. However, immune checkpoint inhibitors were reported to increase response rates and improve outcomes and life expectancy in patients with various cancers, including squamous cell carcinoma in xeroderma pigmentosum. In this paper, we report on a patient with xeroderma pigmentosum from a consanguineous family with recurrent facial chemotherapy-resistant squamous cell carcinoma lesions treated successfully with an anti-programmed cell death protein 1 monoclonal antibody in both relapses.

CASE PRESENTATION

A 7-year-old Turkish male was referred to our oncology department for recurring squamous cell carcinoma after local excision of the tumor over his nose. The lesion was a rapidly growing lesion, measuring 8 × 4 cm in size. Physical examination revealed that he also had hemorrhagic crusted plaques and nodules over both eyelids and upper lip, with multiple hypo- and hyperpigmented punctate lesions all over his body. After two more cycles of chemotherapy, progressive disease was noted, and a new lesion on the right eyelid caused blurred vision. Anti-programmed cell death protein 1 antibody treatment was planned with concomitant radiotherapy. He received nivolumab every 3 weeks for 4 months, improving his vision. No new lesions or active complaints have been observed in the current situation, and complete remission has been achieved. On the last admission, the patient was clinically diagnosed with xeroderma pigmentosum. Owing to the condition's genetic heterogeneity, whole-exome sequencing was performed with Ion Proton next-generation sequencing platform, and the c.2250 + 1G>A splice site mutation of the XPC gene was detected in the homozygous state.

CONCLUSIONS

The clinical report emphasizes the importance of clinical awareness and crucial early diagnosis of xeroderma pigmentosum and presents a novel causative homozygous c.2250 + 1G>A splice site mutation. Our case proves that next-generation sequencing is an effective method for the rapid diagnosis and determination of xeroderma pigmentosum genetic etiology.

Current state of knowledge of human DNA polymerase eta protein structure and disease-causing mutations

POLη, encoded by the POLH gene, is a crucial protein for replicating damaged DNA and the most studied specialized translesion synthesis polymerases. Mutations in POLη are associated with cancer and the human syndrome xeroderma pigmentosum variant, which is characterized by extreme photosensitivity and an increased likelihood of developing skin cancers. The myriad of structural information about POLη is vast, covering dozens of different mutants, numerous crucial residues, domains, and posttranslational modifications that are essential for protein function within cells. Since POLη is key vital enzyme for cell survival, and mutations in this protein are related to aggressive diseases, understanding its structure is crucial for biomedical sciences, primarily due to its similarities with other Y-family polymerases and its potential as a targeted therapy-drug for tumors. This work provides an up-to-date review on structural aspects of the human POLη: from basic knowledge about critical residues and protein domains to its mutant variants, posttranslational modifications, and our current understanding of therapeutic molecules that target POLη. Thus, this review provides lessons about POLη's structure and gathers critical discussions and hypotheses that may contribute to understanding this protein's vital roles within the cells.

Management of coexisting bilateral ocular surface disease in xeroderma pigmentosum - sequence and outcomes

PURPOSE

To report a rare presentation of bilateral, coexisting ocular surface disease in a case of Xeroderma pigmentosum and its successful management.

METHODS

Case report.

RESULTS

A 21-year-old male with Xeroderma pigmentosum presented with bilateral ocular surface squamous neoplasia (OSSN) along with central guttae in the right eye and corneal decompensation of the left eye. Subsequently, the patient developed dry eyes and lid margin keratinization in both eyes followed by perforation in the left eye. Sequential procedures both medical and surgical, including excision of the tumour, corneal transplantation and mucous membrane grafting addressing each of these ocular surface issues resulted in a successful outcome. There was no recurrence of the tumour over 3 years. Corneal transplantation is preferably done after a minimum of 6 months following excision. Mucous membrane grafting performed for progressive lid margin keratinization resulted in surface stabilization.

CONCLUSIONS

In Xeroderma Pigmentosum, multiple ocular surface features can rarely coexist and be bilateral. Periodic evaluation of the surface for tumours, progressive dry eyes and endothelial function is recommended as a part of routine evaluation in Xeroderma pigmentosum. Surface procedures should precede intraocular intervention. Sequential management can result in successful outcomes.

Revisiting the structural features of the xeroderma pigmentosum proteins: Focus on mutations and knowledge gaps

The nucleotide excision repair pathway is a broadly studied DNA repair mechanism because impairments of its key players, the xeroderma pigmentosum proteins (XPA to XPG), are associated with multiple hereditary diseases. Due to the massive number of novel mutations reported for these proteins and new structural data published every year, proper categorization and discussion of relevant observations is needed to organize this extensive inflow of knowledge. This review aims to revisit the structural data of all XP proteins while updating it with the information developed in of the past six years. Discussions and interpretations of mutation outcomes, mechanisms of action, and knowledge gaps regarding their structures are provided, as well as new perspectives based on recent research.

First report of oral angiokeratoma in a xeroderma pigmentosum

Introduction and importance

Xeroderma pigmentosum is an autosomal recessive genetic disorder with impaired ability to repair DNA damage. Detection of the intraoral benign and malignant lesion in Xeroderma pigmentosum is uncommon, and the reported few cases were in the lip and tip of the tongue which are related to ultraviolet light exposure.

Case presentation

We present a case of 20 years old male with erythematous to violet, painless and shiny papule at the right side of the tongue. The lesion was surgically excised while the histopathological examination of the lesion showed focally eroded and hyperplastic stratified squamous epithelial covering with underlying capillary sized blood vessel filled with RBCs and lined by endothelium with no atypia or malignancy.

Clinical discussion

Oral angiokeratoma is a rare disease in patient with Xeroderma pigmentosum that should be early detected and diagnosed to decrease the liability for malignant transformation.

Conclusion

Health case workers should be aware of the nature of the disease, protection of the patient from ultraviolet light as well as Frequent follow up of the patients for a better quality of life.

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The management of XP complications, especially orofacial manifestations, represents a considerable challenge to healthcare providers.

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Angiokeratomas are vascular malformations of capillaries in the form of single or multiple keratotic papules and/or plaques.

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Health case workers should be aware of disease’s nature and the follow up of the patient for a better of life.

Severe cisplatin-induced renal toxicity in a patient with xeroderma pigmentosum

INTRODUCTION

Xeroderma pigmentosum is a rare genetic disorder of DNA repair, defined by extreme sensitivity to sunlight, leading to sunburn, skin pigmentation and increased incidence of skin cancers. Cisplatin acts by interfering with DNA repair mechanisms to cause DNA damage and apoptosis. It has indications in many malignancies including bladder, head and neck and lung cancers. Acute kidney injury is a well-known complication of cisplatin.

CASE REPORT

We report a 42-year-old male with a long history of Xeroderma pigmentosum treated with adjuvant cisplatin (40 mg/m²) in combination with radiotherapy for cutaneous squamous cell carcinoma of the neck. He presented to clinic prior to his second weekly dose of cisplatin with a severe acute kidney injury and a creatine level of 813 mmol/L and eGFR of 7 mL/min. No myelosuppression was present.

MANAGEMENT AND OUTCOME

Treatment consisted of aggressive electrolyte and fluid management. Creatinine levels slowly improved with conservative management without the need for dialysis. Radiation was completed without further cisplatin.

DISCUSSION

Three cases of severe adverse effects from cisplatin administration in patients with Xeroderma pigmentosum have been reported, with all fatal. Xeroderma pigmentosum complementation group C plays an important role in the DNA repair process with the recognition and repair of damage to normal cells following cisplatin. Patients with Xeroderma pigmentosum can be carriers of defective Xeroderma pigmentosum complementation group C and if the degree of Xeroderma pigmentosum complementation group C inactivity is significant, fatalities could occur. Physicians should be aware of this rare but potentially lethal toxicity when considering systemic therapy for squamous cell carcinoma in patients diagnosed with Xeroderma pigmentosum.

Differences in peripheral neuropathy in xeroderma pigmentosum complementation groups A and D as evaluated by nerve conduction studies

Background

Xeroderma pigmentosum (XP) is a rare autosomal recessive genetic disorder with defective DNA nucleotide excision repair and associated with a high frequency of skin cancer. Approximately 25% of patients develop progressive neurological degeneration. Complementation groups XP-A and XP-D are most frequently associated with neurological disorders.

Design/methods

This is a retrospective review of patients with XP who were evaluated at NIH from 1986 to 2015 and had nerve conduction studies (NCS). In the complementation groups with peripheral neuropathy, further comparisons of the NCS were made with audiological, brain imaging, neuropsychological assessments that were also performed on most of the patients. Limited neuropathology of XP-A and XP-D patients were examined..

Results

The 33 patients had NCS: XP-A (9 patients), XP-C (7 patients), XP-D (10 patients), XP-E (1 patient), XP-V (4 patients), and XP-unknown (2 patients). Peripheral neuropathy based on nerve conduction studies was documented only in two complementation groups: 78% (7/9) of XP-A patients had a sensorimotor neuropathy while 50% (5/10) of XP-D patients had a sensory neuropathy only. Analysis of sural sensory nerve amplitude in both complementation groups XP-A and XP-D correlated with sensorineural hearing loss (SNHL), MRI/CT severity, and Full-scale Intelligence Quotient (IQ). Analysis of fibular motor nerve amplitude in complementation XP-A correlated with SNHL and MRI/CT severity. Limited follow-up studies showed gradual loss of NCS responses compared to an earlier and more rapid progression of the hearing loss.

Conclusions

Despite similar brain imaging and audiological findings patients, XP-A and XP-D complementation groups differ in the type of neuropathy, sensorimotor versus sensory alone. A few cases suggest that sensorineural hearing loss may precede abnormal NCS in XP and therefore serve as valuable clinical indicators of XP patients that will later develop peripheral neuropathy.

Xeroderma pigmentosum and acute myeloid leukemia: a case report

BACKGROUND

Xeroderma pigmentosum is a rare inherited disease characterized by extreme hypersensitivity to ultraviolet rays and predisposing to cutaneous malignancies that can appear in childhood. These manifestations are often associated with ocular lesions and sometimes with neurological disorders. The association of xeroderma pigmentosum with internal neoplasms such as acute myeloblastic leukemia is not reported with great frequency, which confirms the rarity of this occurrence.

CASE REPORT

A 26-year-old Moroccan women, xeroderma pigmentosum patient, was diagnosed with acute myeloblastic leukemia with a complex karyotype. Due to the adverse risk of the xeroderma pigmentosum association with acute myeloblastic leukemia and the profile of acute myeloblastic leukemia with complex karyotype and monosomy 7, which constitute factors of poor prognosis, as well as the absence of studies conceding the tolerance of the chemotherapy by patients suffering from xeroderma pigmentosum, our patient was put under low-dose cytarabine protocol with granulocyte colony-stimulating factor. Unfortunately, she died on the tenth day of chemotherapy by acute pulmonary edema of cardiogenic pace complicated by tamponade.

CONCLUSION

According to reports, it is the second case showing association of xeroderma pigmentosum with acute myeloblastic leukemia. The management of these patients remains a challenge. Studies focusing on xeroderma pigmentosum patients developing hematological malignancies are necessary to better understand the most appropriate strategies and precautions for this specific case.

Impact of DNA sequences on DNA 'opening' by the Rad4/XPC nucleotide excision repair complex

Rad4/XPC recognizes diverse DNA lesions to initiate nucleotide excision repair (NER). However, NER propensities among lesions vary widely and repair-resistant lesions are persistent and thus highly mutagenic. Rad4 recognizes repair-proficient lesions by unwinding ('opening') the damaged DNA site. Such 'opening' is also observed on a normal DNA sequence containing consecutive C/G's (CCC/GGG) when tethered to Rad4 to prevent protein diffusion. However, it was unknown if such tethering-facilitated DNA 'opening' could occur on any DNA or if certain structures/sequences would resist being 'opened'. Here, we report that DNA containing alternating C/G's (CGC/GCG) failed to be opened even when tethered; instead, Rad4 bound in a 180°-reversed manner, capping the DNA end. Fluorescence lifetime studies of DNA conformations in solution showed that CCC/GGG exhibits local pre-melting that is absent in CGC/GCG. In MD simulations, CGC/GCG failed to engage Rad4 to promote 'opening' contrary to CCC/GGG. Altogether, our study illustrates how local sequences can impact DNA recognition by Rad4/XPC and how certain DNA sites resist being 'opened' even with Rad4 held at that site indefinitely. The contrast between CCC/GGG and CGC/GCG sequences in Rad4-DNA recognition may help decipher a lesion's mutagenicity in various genomic sequence contexts to explain lesion-determined mutational hot and cold spots.

Transcription-coupled repair and the transcriptional response to UV-Irradiation

Lesions in genes that result in RNA polymerase II (RNAPII) stalling or arrest are particularly toxic as they are a focal point of genome instability and potently block further transcription of the affected gene. Thus, cells have evolved the transcription-coupled nucleotide excision repair (TC-NER) pathway to identify damage-stalled RNAPIIs, so that the lesion can be rapidly repaired and transcription can continue. However, despite the identification of several factors required for TC-NER, how RNAPII is remodelled, modified, removed, or whether this is even necessary for repair remains enigmatic, and theories are intensely contested. Recent studies have further detailed the cellular response to UV-induced ubiquitylation and degradation of RNAPII and its consequences for transcription and repair. These advances make it pertinent to revisit the TC-NER process in general and with specific discussion of the fate of RNAPII stalled at DNA lesions.

Xeroderma Pigmentosum: Gene Variants and Splice Variants

The nucleotide excision repair (NER) is essential for the repair of ultraviolet (UV)-induced DNA damage, such as cyclobutane pyrimidine dimers (CPDs) and 6,4-pyrimidine-pyrimidone dimers (6,4-PPs). Alterations in genes of the NER can lead to DNA damage repair disorders such as Xeroderma pigmentosum (XP). XP is a rare autosomal recessive genetic disorder associated with UV-sensitivity and early onset of skin cancer. Recently, extensive research has been conducted on the functional relevance of splice variants and their relation to cancer. Here, we focus on the functional relevance of alternative splice variants of XP genes.

Thyroid nodules in xeroderma pigmentosum patients: a feature of premature aging

PURPOSE

Xeroderma pigmentosum (XP) is an autosomal recessive disease with defective DNA repair, a markedly increased risk of skin cancer, and premature aging. Reports from North Africa have described thyroid nodules in XP patients, but thyroid nodule prevalence has never been determined in XP patients enrolled in our natural history study at the National Institutes of Health (NIH).

METHODS

We performed thyroid ultrasound examinations on all 29 XP patients examined from 2011 to 2019 and assessed nodule malignancy using the Thyroid Imaging Reporting and Data System. Thyroid nodule prevalence was also obtained from comparison cohorts. DNA sequencing was performed on thyroid tissue from XP patients who had surgery for thyroid cancer.

RESULTS

Thyroid nodules were identified in 18/29 XP patients (62%). The median age of patients with thyroid nodules in our XP cohort (20 years) was younger than that of three comparison groups: 36 years (California study-208 subjects), 48 years (Korean study-24,757 subjects), and 52 years (NIH-682 research subjects). Multiple (2-4) thyroid nodules were found in 12/18 (67%) of the patients with nodules. Autopsy examination revealed follicular adenomas in 4/8 (50%) additional XP patients. DNA sequencing revealed rare mutations in two other XP patients with papillary thyroid cancer.

CONCLUSIONS

XP patients have an increased incidence of thyroid nodules at an early age in comparison to the general population. These finding confirm another premature aging feature of XP.

Lung adenocarcinoma concomitant with xeroderma pigmentosum: a case report

BACKGROUND

Xeroderma pigmentosum is a rare, autosomal-recessive photosensitive dermatosis. Patients with xeroderma pigmentosum have an impaired ability to repair deoxyribonucleic acid damage caused by ultraviolet rays, resulting in skin cancer. Patients with xeroderma pigmentosum are more susceptible to some cancers. We herein report a case of xeroderma pigmentosum accompanied by lung cancer.

CASE PRESENTATION

The patient was a Japanese woman in her 70s with a family history of consanguineous marriage. Her medical history included squamous cell carcinoma and basal cell carcinoma, in addition to xeroderma pigmentosum. She presented with dry skin with small, pigmented spots, which were particularly focused around the areas exposed to sunlight. Chest computed tomography was conducted to assess for any evidence of metastatic skin carcinoma, and revealed a tumor in the left upper subpleural lobe of the lung. Consequently, she was referred to our department. Finally, we diagnosed lung adenocarcinoma (pT2aN0M1b: stage IVA). She had an epidermal growth factor receptor (EGFR) mutation (p.L858R). Treatment with an epidermal growth factor receptor tyrosine kinase inhibitor (gefitinib) was initiated, and the tumor gradually regressed. No side effects were observed. However, she later died from aspiration pneumonia.

CONCLUSIONS

Although xeroderma pigmentosum is rare, a history of consanguineous marriage should be verified. Because of the severe side effects of cisplatin and radiotherapy in xeroderma pigmentosum patients, the risks and benefits of treatment should be considered thoroughly.

Xeroderma pigmentosum and renal leiomyosarcoma: A very rare case report association

INTRODUCTION

Xeroderma pigmentosum (XP) is a rare genetic disorder causing extreme sensitivity to ultraviolet (UV) rays. It is transmitted by an autosomal recessive mode. This disease is classically characterized by a high risk of skin cancer. The occurrence of extra-dermatological cancers in patients followed for XP has been rarely reported in the literature. We present the case of a 14-year-old adolescent with an exceptional association of XP and renal leiomyosarcoma.

PRESENTATION OF CASE

A 14-year-old adolescent was presented with an abdominal mass revealed by hematuria and abdominal pain. Computed tomography (CT) of the abdomen showed an enhancing, heterogeneous right renal mass, consistent with the features of renal tumor. After non conclusive biopsy, a total nephrectomy of the right kidney was performed. Based on gross specimen observation and immunochemical analysis, the patient was diagnosed with high-grade renal leiomyosarcoma. An adjuvant chemotherapy was indicated and the patient was referred to medical oncology. At 12 months follow-up, the patient is in total remission; The CT scan did not show any locoregional or distant recurrence CONCLUSION: The risk of renal tumor is increased in patients followed for XP. Attending physicians should ask for renal imaging at the slightest sign of clinical call.

Inhabitual presentation of Sertoli-Leydig cell tumor of the ovary with xeroderma pigmentosum: Case report with review of literature

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Sertoli-Leydig cell tumors are rare sex-cord stromal tumors of the ovary.

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We present a case of Sertoli-Leydig cell tumors with rhabdomyomatous differentiation on the setting of xeroderma pigmentosum.

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We describe clinical, gross and microscopic examinations for diagnosis and treatment.

Introduction

Sertoli-Leydig cell tumors (SLCTs) are rare sex-cord stromal tumors of the ovary. Heterologous components may be present, most commonly in the intermediate differentiated and poorly differentiated groups. Because of their scarcity, SLCTs with heterologous differentiation represent a challenge in both diagnosis and management, with limited available experience.

Presentation of case

We report a case of a 27-year-old, Tunisian woman, followed in the Dermatology Department since the age of six months for xeroderma pigmentosum, with a history of basal cell carcinoma of the face operated on several times. The patient presented with abdominal pain and bloating associated with a medium abundance ascites on physical exam. Ultrasound showed a large left adnexal mass associated with an elevated cancer antigen 125 on serological exam. The patient underwent unilateral salpingo-oophorectomy with resection of two omental nodules. Microscopic examination concluded to poorly differentiated Sertoli-Leydig tumor with rhabdomyomatous differentiation. Adjuvant chemotherapy was performed and there was no clinical evidence of tumor recurrence during the three years of follow-up.

Discussion

SLCTs with rhabdomyomatous differentiation on the setting of xeroderma pigmentosum are exceptional, microscopic diagnosis and management is challenging, considering the tumor scarcity.

Conclusion

Further case reports and retrospective studies are required to more understand the pathogenesis of SLCTs and to determine their optimal treatment regimen.

A novel DDB2 mutation causes defective recognition of UV-induced DNA damages and prevalent equine squamous cell carcinoma

Squamous cell carcinoma (SCC) occurs frequently in the human Xeroderma Pigmentosum (XP) syndrome and is characterized by deficient UV-damage repair. SCC is the most common equine ocular cancer and the only associated genetic risk factor is a UV-damage repair protein. Specifically, a missense mutation in horse DDB2 (T338M) was strongly associated with both limbal SCC and third eyelid SCC in three breeds of horses (Halflinger, Belgian, and Rocky Mountain Horses) and was hypothesized to impair binding to UV-damaged DNA. Here, we investigate DDB2-T338M mutant's capacity to recognize UV lesions in vitro and in vivo, together with human XP mutants DDB2-R273H and -K244E. We show that the recombinant DDB2-T338M assembles with DDB1, but fails to show any detectable binding to DNA substrates with or without UV lesions, due to a potential structural disruption of the rigid DNA recognition β-loop. Consistently, we demonstrate that the cellular DDB2-T338M is defective in its recruitment to focally radiated DNA damages, and in its access to chromatin. Thus, we provide direct functional evidence indicating the DDB2-T338M recapitulates molecular defects of human XP mutants, and is the causal loss-of-function allele that gives rise to equine ocular SCCs. Our findings shed new light on the mechanism of DNA recognition by UV-DDB and on the initiation of ocular malignancy.

XPA deficiency affects the ubiquitin-proteasome system function

Xeroderma pigmentosum complementation group A (XPA), is defective in xeroderma pigmentosum patients, causing pre-disposition to skin cancer and neurological abnormalities, which is not well understood. Here, we analyzed the XPA-deficient cells transcriptional profile under oxidative stress. The imbalance in of ubiquitin-proteasome system (UPS) gene expression was observed in XPA-deficient cells and the involvement of nuclear factor erythroid 2-related factor-2 (NFE2L2) was indicated. Co-immunoprecipitation assays showed the interaction between XPA, apurinic-apyrimidinic endonuclease 1 (APE1) and NFE2L2 proteins. Decreased NFE2L2 protein expression and proteasome activity was also observed in XPA-deficient cells. The data suggest the involvement of the growth arrest and DNA-damage-inducible beta (GADD45β) in NFE2L2 functions. Similar results were obtained in xpa-1 (RNAi) Caenorhabditis elegans suggesting the conservation of XPA and NFE2L2 interactions. In conclusion, stress response activation occurs in XPA-deficient cells under oxidative stress; however, these cells fail to activate the UPS cytoprotective response, which may contribute to XPA patient's phenotypes.

A case of lip squamous cell carcinoma with a familial history of Xeroderma pigmentosum

Xeroderma pigmentosum is an orphan hereditary photosensitive human disorder that is recognized by the development of skin lesions in sun-exposed regions of the body due to severe photosensitivity. Patients with this condition have an abnormal DNA repair process due to a genetic mutation. Xeroderma pigmentosum is considered as a risk factor of cancer since the affected population may develop various cutaneous cancers including both melanoma and non-melanoma cutaneous malignancies even at a younger age than the general population. This risk concerns also asymptomatic heterozygote individuals. Here, we present a case of 46 years old man with a familial history of Xeroderma pigmentosum who developed a microscopically confirmed squamous cell carcinoma of the lip.

Corneal endothelial assessment in xeroderma pigmentosum: a case-control study

PURPOSE

To analyze and compare corneal endothelial mosaic in terms of endothelial cell population, morphology and irregularity in patients with xeroderma pigmentosum (XP) with clear corneas with normal age and sex matched subjects using specular microscopy.

METHODS

Nine patients with XP without corneal involvement were evaluated in the study. An age and sex matched group of nine healthy subjects participated as control group. Evaluation of corneal endothelial layer was performed using specular microscopy.

RESULTS

Each study group consisted of five males and four females with total mean age of 28 ± 11.3 years (12-46 years). Endothelial cell density was significantly lower in patients with XP in comparison with controls (P < 0.002). Maximum and minimum cell areas were significantly higher in XP group (P < 0.016 and P < 0.029, respectively). Although central corneal thickness was higher in controls, the difference was not statistically significant (P = 0.106). Furthermore, our study showed that the patients with XP had no difference with controls in terms of coefficient of variation of cell areas.

CONCLUSIONS

This study showed that endothelial cell population can decrease in patients with XP, although other specular microscopic variables such as coefficient of variation and central corneal thickness may remain within normal values.

Expanding molecular roles of UV-DDB: Shining light on genome stability and cancer

UV-damaged DNA binding protein (UV-DDB) is a heterodimeric complex, composed of DDB1 and DDB2, and is involved in global genome nucleotide excision repair. Mutations in DDB2 are associated with xeroderma pigmentosum complementation group E. UV-DDB forms a ubiquitin E3 ligase complex with cullin-4A and RBX that helps to relax chromatin around UV-induced photoproducts through the ubiquitination of histone H2A. After providing a brief historical perspective on UV-DDB, we review our current knowledge of the structure and function of this intriguing repair protein. Finally, this article discusses emerging data suggesting that UV-DDB may have other non-canonical roles in base excision repair and the etiology of cancer.

Photodynamic therapy in the treatment of xeroderma pigmentosum: A case report

Xeroderma pigmentosum (XP) is a rare autosomal recessive dermatosis that is often complicated by multiple skin tumours at exposed locations, which are difficult to treat. We report a case of a 12-year-old girl with XP treated with oral retinoic acid and photodynamic therapy (PDT) with good clinical results. She had an 8-year history of multiple skin lesions that first appeared on her nasal dorsum, but gradually increased in size and spread to her entire face, neck, and upper limbs. Notably, the lesions became evidently aggravated after sun exposure. When she was 6 years old, sesame-seed-sized papules and plaques appeared, which were fragile and irregular in shape and would self-rupture, accompanied with slight itchiness and bloody exudate. Examination revealed multiple basal cell carcinomas. The tumours were treated with local carbon dioxide laser therapy combined with PDT. On the follow-up visit 2 months after the surgery, most of the skin lesions on her face had subsided. In cases of multiple tumours, PDT can be the treatment method of choice because it is less invasive, has less side effects, and does not damage the surrounding normal tissues.

Identification of a novel DDB2 mutation in a Chinese Han family with Xeroderma pigmentosum group E:a case report and literature review

Background

Xeroderma pigmentosum (XP) is a rare autosomal recessive genodermatosis. There are eight complementation groups of XP (XP-A to G and a variant form). XP-E is one of the least common forms, and XP-E patients are generally not diagnosed until they are adults due to a later onset of skin alterations.

Case presentation

We report a case of a 28-year-old Chinese woman with freckle-like hyperpigmented macules in a sun-exposed area who is prone to develop basal cell carcinomas. A genetic study revealed a novel homozygous c.111_112del deletion in exon 1 of the DDB2 gene. Western blotting analysis revealed that the patient lacked the expression of the wild-type mature DDB2 protein. The proband was first diagnosed with XPE on the basis of clinical findings and genetic testing. Sun protection was recommended, and the patient did not develop any skin cancers during the one-year follow-up.

Conclusions

We identified a novel homozygous deletion in DDB2 gene in Chinese XP-E patients having unique clinical features.

The Iberian legacy into a young genetic xeroderma pigmentosum cluster in central Brazil

In central Brazil, in the municipality of Faina (state of Goiás), the small and isolated village of Araras comprises a genetic cluster of xeroderma pigmentosum (XP) patients. The high level of consanguinity and the geographical isolation gave rise to a high frequency of XP patients. Recently, two founder events were identified affecting that community, with two independent mutations at the POLH gene, c.764 + 1 G > A (intron 6) and c.907 C > T; p.Arg303* (exon 8). These deleterious mutations lead to the xeroderma pigmentosum variant syndrome (XP-V). Previous reports identified both mutations in other countries: the intron 6 mutation in six patients (four families) from Northern Spain (Basque Country and Cantabria) and the exon 8 mutation in two patients from different families in Europe, one of them from Kosovo. In order to investigate the ancestry of the XP patients and the age for these mutations at Araras, we generated genotyping information for 22 XP-V patients from Brazil (16), Spain (6) and Kosovo (1). The local genomic ancestry and the shared haplotype segments among the patients showed that the intron 6 mutation at Araras is associated with an Iberian genetic legacy. All patients from Goiás, homozygotes for intron 6 mutation, share with the Spanish patients identical-by-descent (IBD) genomic segments comprising the mutation. The entrance date for the Iberian haplotype at the village was calculated to be approximately 200 years old. This result is in agreement with the historical arrival of Iberian individuals at the Goiás state (BR). Patients from Goiás and the three families from Spain share 1.8 cM (family 14), 1.7 cM (family 15), and a more significant segment of 4.7 cM within family 13. On the other hand, the patients carrying the exon 8 mutation do not share any specific genetic segment, indicating an old genetic distance between them or even no common ancestry.

Conjunctival melanoma in patients with xeroderma pigmentosum: a series of four cases

PURPOSE

To study the demographic features, treatment, histopathology, and outcomes in patients of xeroderma pigmentosum (XP) with conjunctival melanoma.

METHODS

Retrospective case series.

RESULTS

The median age at presentation was 18 years (range 9-30 years). There were three females and one male patient presenting with a median duration of symptoms of 3 months (range 1-60 months). The tumor was located in the bulbar conjunctiva in all 4 patients. All patients had corneal involvement by the tumor. The median tumor basal diameter was 7 mm (range 4-15 mm). Wide tumor excisional biopsy with alcohol keratoepithelectomy, cryotherapy to the free margins, and amniotic membrane grafting was done in three patients. One patient underwent orbital exenteration for extensive tumor. One patient also received adjuvant plaque brachytherapy for microscopic residual tumor. Over a median follow-up of 22 months (range 2-101 months), there were no recurrences, metastasis, or death.

CONCLUSION

Conjunctival melanoma in XP is rare and manifests at a younger age.

Daylight photodynamic therapy is an option for the treatment of actinic keratosis in patients with xeroderma pigmentosum in Africa

BACKGROUND

Xeroderma pigmentosum (XP) is a very rare and severe genetic disorder with a DNA repair defect of ultraviolet (UV)-induced damage. Photodynamic therapy (PDT) has been successfully used in XP patients to treat actinic keratosis (AK) and daylight PDT (DL-PDT) has demonstrated similar efficacy to conventional PDT (C-PDT) for AK.

OBJECTIVES

To assess DL-PDT for the treatment of AK in patients with XP.

METHODS

Patients with XP were evaluated by a group of Spanish and African dermatologists. Clinical characteristics of the patients were assessed and divided in mild, severe or moderate affectation of AK in the face. A topical photosensitizer was extended on the patients' faces and after two hours of indoor light exposure, fluorescence was assessed and the cream was removed. Patients were examined two and seven days later to assess the reaction to PDT and followed up three months later.

RESULTS

A total of 13 patients were treated on the whole face. Three were classified as severe AK, six as moderate AK and four as mild AK. Fluorescence assessment showed a soft yellow-green colour and a pink-color delineating the AK. Two days after treatment patients presented a scaly reaction. After one week the reaction healed, there was improvement and after three months no adverse events were noticed.

CONCLUSIONS

PDT is an option for treatment of AK in patients with XP.

Molecular Biology of Basal and Squamous Cell Carcinomas

The prevalent keratinocyte-derived neoplasms of the skin are basal cell carcinoma and squamous cell carcinoma. Both so-called non-melanoma skin cancers comprise the most common cancers in humans by far. Common risk factors for both tumor entities include sun exposure, DNA repair deficiencies leading to chromosomal instability, or immunosuppression. Yet, fundamental differences in the development of the two different entities have been and are currently unveiled. The constitutive activation of the sonic hedgehog signaling pathway by acquired mutations in the PTCH and SMO genes appears to represent the early basal cell carcinoma developmental determinant. Although other signaling pathways are also affected, small hedgehog inhibitory molecules evolve as the most promising basal cell carcinoma treatment options systemically as well as topically in current clinical trials. For squamous cell carcinoma development, mutations in the p53 gene, especially UV-induced mutations, have been identified as early events. Yet, other signaling pathways including epidermal growth factor receptor, RAS, Fyn, or p16INK4a signaling may play significant roles in squamous cell carcinoma development. The improved understanding of the molecular events leading to different tumor entities by de-differentiation of the same cell type has begun to pave the way for modulating new molecular targets therapeutically with small molecules.

Neurogenic bladder associated with xeroderma pigmentosum type A: A case report and literature review

Xeroderma pigmentosum (XP) is a rare autosomal recessive disease caused by a defect in deoxyribonucleic acid repair. Along with cutaneous symptoms, neurological symptoms are important clinical features of XP. However, information on neurogenic bladder occurrence among XP cases is rare. Herein, we describe a case of neurogenic bladder in a patient with XP type A (XPA). In this case, low bladder compliance, impaired bladder emptying, and urethral sphincter discoordination were significant cystometric findings, and frequent febrile urinary tract infection was a clinical problem. XPA patients often cannot express their symptoms because of cognitive dysfunction. Close follow-up and assessments are necessary.

Hereditary Tumor Syndromes with Skin Involvement

Cutaneous findings that appear in childhood may be the first sign of a hereditary tumor syndrome. Early detection of genodermatoses allows the patient and at-risk family members to be screened for associated malignancies. This article provides a brief description of the pathogenesis and clinical manifestations of various inherited disorders with skin involvement, along with treatment updates. Advances in molecular-based therapy have spurred development of novel treatment methods for various genodermatoses such as xeroderma pigmentosum (XP) and Gorlin-Goltz syndrome. Further studies are needed to better assess the efficacy of many of these new treatment options.

Frequent retrotransposition of endogenous genes in ERCC2-deficient cells derived from a patient with xeroderma pigmentosum

Background

Retrotransposition of protein-coding genes is thought to occur due to the existence of numerous processed pseudogenes in both animals and plants. Unlike retrotransposons including Alu and LINE-1, direct evidence of such retrotransposition events has not been reported to date. Even if such an event occurs in a somatic cell, it is almost impossible to detect it using bulk of cells as a sample. Single-cell analyses or other techniques are needed.

Methods

In order to examine genetic stability of stem cells, we have established induced pluripotent stem cell (iPSC) lines from several patients with DNA repair-deficiency disorders, such as ataxia telangiectasia and xeroderma pigmentosum, along with healthy controls. Performing whole-exome sequencing analyses of these parental and iPSC lines, we compiled somatic mutations accumulated by the deficiency of DNA repair mechanisms. Whereas most somatic mutations cannot be detected in bulk, cell reprogramming enabled us to observe all the somatic mutations which had occurred in the cell line. Patterns of somatic mutations should be distinctive depending on which DNA repair gene is impaired.

Results

The comparison revealed that deficiency of ATM and XPA preferentially gives rise to indels and single-nucleotide substitutions, respectively. On the other hand, deficiency of ERCC2 caused not only single-nucleotide mutations but also many retrotranspositions of endogenous genes, which were readily identified by examining removal of introns in whole-exome sequencing. Although the number was limited, those events were also detected in healthy control samples.

Conclusions

The present study exploits clonality of iPSCs to unveil somatic mutation sets that are usually hidden in bulk cell analysis. Whole-exome sequencing analysis facilitated the detection of retrotransposition mutations. The results suggest that retrotranspositions of human endogenous genes are more frequent than expected in somatic cells and that ERCC2 plays a defensive role against transposition of endogenous and exogenous DNA fragments.

Damage removal and gap filling in nucleotide excision repair

The nucleotide excision repair (NER) system removes a variety of types of helix-distorting lesions from DNA through a dual incision mechanism, in which the damaged nucleotide bases are excised in the form of a small, excised, damage-containing single-stranded DNA oligonucleotide (sedDNA). Damage removal leaves a gap in the DNA template that must then be filled in by the action of a DNA polymerase and ligated to the downstream phosphodiester backbone in the DNA to complete the repair reaction. Defects in damage removal, sedDNA processing, or gap filling have the potential to be mutagenic and lethal to cells, and thus several human pathologies, including cancer and aging, are associated with defects in NER. This review summarizes our current understanding of NER with a focus on the enzymes that excise sedDNAs and restore the duplex DNA to its native state in human cells.

Corneoscleral locally aggressive fibrous histiocytoma in Xeroderma Pigmentosum patient: A case report

Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder that has been found in all continents and racial groups in relation to faulty repair of DNA with sun exposure. Several cutaneous and ocular tumors have been described in relation to XP including fibrous histiocytoma (FH). The diagnosis of conjunctival FH is challenging owing to the rarity of this tumor and the diversity of its classification into benign, locally aggressive and malignant. We are describing a recurrent FH exhibiting a locally aggressive behavior in a child with history of XP. Detailed histopathological features are presented with literature review.

Spironolactone-induced degradation of the TFIIH core complex XPB subunit suppresses NF-κB and AP-1 signalling

Aims

Spironolactone (SPL) improves endothelial dysfunction and survival in heart failure. Immune modulation, including poorly understood mineralocorticoid receptor (MR)-independent effects of SPL might contribute to these benefits and possibly be useful in other inflammatory cardiovascular diseases such as pulmonary arterial hypertension.

Methods and results

Using human embryonic kidney cells (HEK 293) expressing specific nuclear receptors, SPL suppressed NF-κB and AP-1 reporter activity independent of MR and other recognized nuclear receptor partners. NF-κB and AP-1 DNA binding were not affected by SPL and protein synthesis blockade did not interfere with SPL-induced suppression of inflammatory signalling. In contrast, proteasome blockade to inhibit degradation of xeroderma pigmentosum group B complementing protein (XPB), a subunit of the general transcription factor TFIIH, or XPB overexpression both prevented SPL-mediated suppression of inflammation. Similar to HEK 293 cells, a proteasome inhibitor blocked XPB loss and SPL suppression of AP-1 induced target genes in human pulmonary artery endothelial cells (PAECs). Unlike SPL, eplerenone (EPL) did not cause XPB degradation and failed to similarly suppress inflammatory signalling. SPL combined with siRNA XPB knockdown further reduced XPB protein levels and had the greatest effect on PAEC inflammatory gene transcription. Using chromatin-immunoprecipitation, PAEC target gene susceptibility to SPL was associated with low basal RNA polymerase II (RNAPII) occupancy and TNFα-induced RNAPII and XPB recruitment. XP patient-derived fibroblasts carrying an N-terminal but not C-terminal XPB mutations were insensitive to both SPL-mediated XPB degradation and TNFα-induced target gene suppression. Importantly, SPL treatment decreased whole lung XPB protein levels in a monocrotaline rat model of pulmonary hypertension and reduced inflammatory markers in an observational cohort of PAH patients.

Conclusion

SPL has important anti-inflammatory effects independent of aldosterone and MR, not shared with EPL. Drug-induced, proteasome-dependent XPB degradation may be a useful therapeutic approach in cardiovascular diseases driven by inflammation.

High levels of oxidatively generated DNA damage 8,5'-cyclo-2'-deoxyadenosine accumulate in the brain tissues of xeroderma pigmentosum group A gene-knockout mice

Xeroderma pigmentosum (XP) is a genetic disorder associated with defects in nucleotide excision repair, a pathway that eliminates a wide variety of helix-distorting DNA lesions, including ultraviolet-induced pyrimidine dimers. In addition to skin diseases in sun-exposed areas, approximately 25% of XP patients develop progressive neurological disease, which has been hypothesized to be associated with the accumulation of an oxidatively generated type of DNA damage called purine 8,5'-cyclo-2'-deoxynucleoside (cyclopurine). However, that hypothesis has not been verified. In this study, we tested that hypothesis by using the XP group A gene-knockout (Xpa^-/-) mouse model. To quantify cyclopurine lesions in this model, we previously established an enzyme-linked immunosorbent assay (ELISA) using a monoclonal antibody (CdA-1) that specifically recognizes 8,5'-cyclo-2'-deoxyadenosine (cyclo-dA). By optimizing conditions, we increased the ELISA sensitivity to a detection limit of ˜one cyclo-dA lesion/10⁶ nucleosides. The improved ELISA revealed that cyclo-dA lesions accumulate with age in the brain tissues of Xpa^-/- and of wild-type (wt) mice, but there were significantly more cyclo-dA lesions in Xpa^-/- mice than in wt mice at 6, 24 and 29 months of age. These findings are consistent with the long-standing hypothesis that the age-dependent accumulation of endogenous cyclopurine lesions in the brain may be critical for XP neurological abnormalities.

Skin cancers in patients of skin phototype V or VI with xeroderma pigmentosum type C (XP-C): A retrospective study

BACKGROUND

Xeroderma pigmentosum (XP) is a rare genetic disease comprising 7 subgroups, A to G, all of which are associated with early onset of several forms of skin cancer. Our main objective was to determine the prevalence of skin cancers in a cohort of dark-skinned XP-C patients in Mayotte.

PATIENTS AND METHODS

A single-centre cohort consisting of all XP patients was followed in the island of Mayotte from December 2015 to May 2017 by dermatologists from the University Hospital of Saint-Denis (Reunion) during the course of dermatological missions.

RESULTS

Eighteen patients of median age 12.9 years (7 female/11 male) belonging to 14 families were included. All had XP-C and carried the same mutation. Median age at clinical diagnosis of XP was 1.8 years. A total of 144 skin cancers (94 squamous cell carcinomas [SCC], 30 basal cell carcinomas [BCC], 14 melanomas, 5 sarcomas and 1 sarcomatoid carcinoma) were observed in 11 of the 18 patients (61%). Eleven patients (61%) had at least 1 SCC, 6 (33%) had at least 1 BCC, 6 (33%) had at least 1 melanoma, and 4 (22%) had at least 1 sarcoma. In all, 95.5% of the cancers occurred in light-exposed skin areas. Median age was 5.4 years for the initial cancer and 6.4 years for the second. SCCs and sarcomas occurred earlier than CBCs and melanomas (P<0.0001). All patients had mild to severe poikiloderma and presented photophobia, and 50% had pigmented palmoplantar lesions. One-third had oral mucosal involvement while 78% had ocular or palpebral lesions. Nail and hair involvement was recorded in 17% of patients. The median sun protection score (evaluated on a 7-item scale) was 6/7. The median score on the quality-of-life questionnaire (DLQI) was 4/30. Severity of poikiloderma was significantly correlated with the occurrence of skin cancers.

DISCUSSION AND CONCLUSION

Our cohort showed a high prevalence of skin cancer in XP-C patients of phototype V and VI exposed to UV radiation in a tropical region. SCCs were the most common tumours. The prevalence of melanoma was high, with major risk compared to controls of the same skin phototype. In addition, we found a high prevalence of sarcomas (5 patients). Initial cancers occurred early (5.4 years) compared to data from the literature, and SCCs and sarcomas occurred significantly sooner than melanomas and BCCs.

[Xerodermapigmentosum: Challenge of diagnosis in West Africa]

Xeroderma pigmentosum is related to a defect of the enzymes involved in repairing the oncogenic effects of ultraviolet exposure. The condition is found all over the world, in all ethnicities and races. This rare genodermatosis is often unknown in countries lacking specialist in dermatology. This scarcity and insufficiency of qualified personnel give rise to difficulties in diagnosing this pathology, especially in West Africa where XP is wrongly diagnosed for other pathologies. Objective: To share with colleagues the problem of diagnosis of Xeroderma pigmentosum in countries with insufficient number of dermatologist and poor technical platform. Observation: 21-year-old man, with no pathological history of dermatosis was seeking for medical consultation because of cutaneous dryness and photophobia. Previous visits at several health centers failed to diagnose the condition and no noticeable improvement was seen from given treatment. Verbal questioning found the notion of consanguinity (his father and his mother are cousins, and belong to the same Dogon group). Cutaneous pigmentary disorders were absent at birth but appeared at the age of 12 years. Physical examination highlighted photophobia in addition to specific clinical and paraclinical signs allowed to diagnose Xeroderma pigmentosum varying type. Conclusion: in West Africa, the challenge of diagnosis of Xeroderma pigmentosum is undoubtedly related to a lack of qualified personnel and technical means of diagnosis, which makes its frequency underestimated.

Xeroderma Pigmentosum - Facts and Perspectives

Ultraviolet (UV)-induced DNA lesions are almost exclusively removed by the nucleotide excision repair (NER) pathway, which is essential for prevention of skin cancer development. Patients with xeroderma pigmentosum (XP) are extremely sun sensitive due to a genetic defect in components of the NER cascade. They present with first signs of premature skin aging at an early age, with a considerably increased risk of developing UV-induced skin cancer. XP belongs to the group of DNA repair defective disorders that are mainly diagnosed in the clinic and in hindsight confirmed at the molecular level. Unfortunately, there are no causative treatment options for this rare, autosomal-recessive disorder, emphasizing the importance of an early diagnosis. Subsequently, UV-protective measures such as the reduction of exposure to environmental UV and regular skin cancer screenings should be undertaken to substantially improve prognosis as well as the disease course.

Genetic investigation of XPA gene: high frequency of the c.682C>T mutation in Moroccan XP patients with moderate clinical profile

OBJECTIVE

Xeroderma pigmentosum (XP) is a genetically and clinically heterogeneous disease, associated with an inherited defect in one of eight different genes (XPA to XPG and XPV). In addition to the early onset of the skin manifestations, the XP group A is marked by the presence of a mild to severe neural disorders which appear tardily and worsens with age. In this study, 9 patients with moderate clinical profile belonging to 6 XP families were recruited to determine the XPA mutational spectrum in Morocco, using the direct sequencing of the whole coding region of the XPA gene.

RESULTS

The genetic investigation of the XPA gene showed that 7 from 9 patients were homozygous for the c.682C>T, p.Arg228X mutation, while all their investigated family members were heterozygous. The frequency of this mutation was estimated to be 83.33% (5/6 families) .The molecular analysis of the 5 other exons of the XPA gene, showed that the 2 negative siblings carried no mutation in the XPA gene. This finding suggests that c.682C>T (p.Arg228X) mutation is relatively associated with moderate phenotype in XP group A Moroccan families; this result will also contribute to improve the molecular diagnosis of XP disease in Moroccan patients.

Quantitative analysis of brain atrophy in patients with xeroderma pigmentosum group A carrying the founder mutation in Japan

INTRODUCTION

Xeroderma pigmentosum (XP) is an inherited congenital disease presenting with dermatological and neurological manifestations. In Japan, XP complementation group A (XP-A) is most frequently observed in eight clinical subtypes, and the homozygous founder mutation, IVS3-1G>C in XPA, suffer from severe manifestations including progressive brain atrophy since childhood. In this study, we used magnetic resonance imaging (MRI) and applied volumetric analysis to elucidate the start and the progression of the brain atrophy in these patients.

MATERIAL AND METHODS

Twelve Japanese patients with XP-A carrying the founder mutation and seven controls were included. MRI was performed for each patient once or more. Three-dimensional T1 weighted images were segmented to gray matter, white matter, and cerebrospinal fluid, and each volume was calculated.

RESULTS

Conventional MRI demonstrated progressive whole brain atrophy in patients with XP-A. Moreover, volumetric analysis showed that reductions of total gray matter volumes (GMV) and total brain volumes (TBV) started at the age of five. The slope of reduction was similar in all cases. The GMV and TBV values in controls were higher than those in XP-A cases after the age of five.

CONCLUSIONS

This is the first quantitative report presenting with the progression of brain atrophy in patients with XP-A. It is revealed that the brain atrophy started from early childhood in Japanese patients with XP-A carrying the homozygous founder mutation.

Identification of four novel XPC mutations in two xeroderma pigmentosum complementation group C patients and functional study of XPC Q320X mutant

Xeroderma pigmentosum (XP) is a rare, recessive hereditary disease characterized by sunlight hypersensitivity and high incidence of skin cancer with clinical and genetic heterogeneity. We collected two unrelated Chinese patients showing typical symptoms of XPC without neurologic symptoms. Direct sequencing of XPC gene revealed that patient 1 carried IVS1+1G>A and c.958 C>T mutations, and patient 2 carried c.545_546delTA and c.2257_2258insC mutations. All these four mutations introduced premature terminal codons (PTCs) in XPC gene. The nonsense mutation c.958 C>T yielded truncated mutant Q320X, and we studied its function for global genome repair kinetics. Overexpressed Q320X mutant can localize to site of DNA damage, but it is defective in CPD and 6-4PP repair. Readthrough of PTCs is a new approach to treatment of genetic diseases. We found that aminoglycosides could significantly increase the full length protein expression of Q320X mutant, but NER defects were not rescued in vitro.

Recurrent conjunctival atypical fibroxanthoma in Pigmentosum Xeroderma

CASE REPORT

A 7 year-old boy with Xeroderma Pigmentosum (XP) and who presents a recurrent conjunctival atypical fibroxanthoma after two surgeries. This is the third procedure and the patient is treated with a surgical excision of the tumour and cryotherapy at the surgical bed. Due to the risk of recurrence, topical Mitomycin C 0,02% was added at post-operative care achieving a good clinical outcome.

DISCUSSION

Surgical exeresis with cryotherapy and topical Mitomycin C is an effective treatment for a case of an atypical fibroxanthoma with a high potential for recurrence and invasion. An ophthalmologic follow-up is required for these patients, as well as general paediatric care and support aids.

An investigation of the predictors of photoprotection and UVR dose to the face in patients with XP: a protocol using observational mixed methods

INTRODUCTION

Xeroderma pigmentosum (XP) is a rare genetic condition caused by defective nucleotide excision repair and characterised by skin cancer, ocular and neurological involvement. Stringent ultraviolet protection is the only way to prevent skin cancer. Despite the risks, some patients' photoprotection is poor, with a potentially devastating impact on their prognosis. The aim of this research is to identify disease-specific and psychosocial predictors of photoprotection behaviour and ultraviolet radiation (UVR) dose to the face.

METHODS AND ANALYSIS

Mixed methods research based on 45 UK patients will involve qualitative interviews to identify individuals' experience of XP and the influences on their photoprotection behaviours and a cross-sectional quantitative survey to assess biopsychosocial correlates of these behaviours at baseline. This will be followed by objective measurement of UVR exposure for 21 days by wrist-worn dosimeter and daily recording of photoprotection behaviours and psychological variables for up to 50 days in the summer months. This novel methodology will enable UVR dose reaching the face to be calculated and analysed as a clinically relevant endpoint. A range of qualitative and quantitative analytical approaches will be used, reflecting the mixed methods (eg, cross-sectional qualitative interviews, n-of-1 studies). Framework analysis will be used to analyse the qualitative interviews; mixed-effects longitudinal models will be used to examine the association of clinical and psychosocial factors with the average daily UVR dose; dynamic logistic regression models will be used to investigate participant-specific psychosocial factors associated with photoprotection behaviours.

ETHICS AND DISSEMINATION

This research has been approved by Camden and King's Cross Research Ethics Committee 15/LO/1395. The findings will be published in peer-reviewed journals and presented at national and international scientific conferences.

An assay to detect DNA-damaging agents that induce nucleotide excision-repairable DNA lesions in living human cells

Biochemical risk assessment studies of chemicals that induce DNA lesions are important, because lesions in genomic DNA frequently result in cancer, neurodegeneration, and aging in humans. Many classes of DNA lesions induced by chemical agents are eliminated via DNA repair mechanisms, such as nucleotide excision repair (NER) and base excision repair (BER), for the maintenance of genomic integrity. Individuals with NER-defective xeroderma pigmentosum (XP), in which bulky DNA lesions are not efficiently removed, are cancer-prone and suffer neurodegeneration. For research into cancer and neurological diseases, therefore, it might be important to identify DNA damage from agents that induce NER-repairable bulky DNA lesions. However, simple and quick assays to detect such damaging agents have not been developed using human cells. Here, we report a simple, non-isotopic assay for determining DNA damaging agents that induce NER-repairable DNA lesions by visualizing gene expression from treated fluorescent protein vectors in a mammalian cell system. This assay is based on a comparison of fluorescent protein expression in NER-proficient and NER-deficient cells. When we tested UV-irradiated fluorescent protein vectors, the fluorescent protein was observed in NER-proficient cells, but not in NER-deficient cells. Similar results were obtained for vectors treated with the anticancer drug, cisplatin. In contrast, when treated with the DNA alkylating agent methyl methanesulfonate, believed to cause BER-repairable damage, no difference in gene expression between NER-proficient and NER-deficient cells was observed. These results suggest that our assay can specifically detect DNA-damaging agents that induce NER-repairable DNA lesions, and could be used to analyze chemicals with the potential to cause cancer and neurological diseases. With further validation, the assay might be also applicable to XP diagnosis.