Xeroderma Pigmentosum

Xeroderma pigmentosum(XP) is a rare autosomal recessive disease, in which the ability of the DNA repair is impaired, symptom presentation is majorly observed over the skin exposed to sunlight and can range from minor hyperpigmentation to ulcerative nodules. We report a rare case of skin cancer associated with xeroderma pigmentosum, in a 6-year-old male child, admitted in a cancer hospital. Initially, the patient was treated for xeroderma pigmentosum. The condition exaggerated and took a form of skin cancer with presentation of distributed pattern of hypo and hyper pigmented macules. Lesions were closely aggregated over the face with ulcerative nodules over scalp, nose, near inner canthus of the eyes. The patient underwent excision followed by reconstruction and post-procedure external beam radiotherapy (EBRT) with the dose of 54Gy/30 in fraction for 6week. The condition did not resolved; patient then underwent radiofrequency excision of scalp nodule with electrosurgical excision of outgrowing lesion in medial canthus under general anesthesia (GA), and was maintained on isotretinoin 10mg with photoprotection. Procedure of electro chemotherapy was done, with intra-tumoral injection (2000 IU Bleomycin) at multiple sites covering entire tumor area in 8 pulses of 100µs on left facial lesion and wide local excision (WLE) with full thickness graft of medial canthus lesion was performed using diathermy.

Objectives: This review aimed to group studies related to xeroderma pigmentosum, presenting their means of diagnosis and current therapeutic strategies. Methods: A search was carried out in the PubMed and Virtual Health Library (BVSALUD) databases using the descriptors: "XERODERMA PIGMENTOSUM", "XERODERMA PIGMENTOSO", "DNA REPAIR", "SKIN CANCER", "PHOTOSENSITIVITY", "CUTANEOUS NEOPLASMS" and "PHOTOSENSITIVITY" in the last 10 years, analyzing and applying the inclusion and exclusion criteria. In the end, 8 articles were selected. Discussion: Xeroderma Pigmentosum is an autosomal recessive disease, being of hereditary character and that increases the prevalence of cutaneous neoplasms and is subdivided into 7 groups in which the error is in the NER protein (Nucleotide Excision Repair) and 1 group with defect in the DNA polymerase. Based on the intensity and type of UV light and on the mutation presented, the clinical picture may vary, being milder or more aggressive, and may affect only the skin, nervous system or more than one system, also causing internal tumors. The diagnosis is clinical, but molecular tests to evaluate DNA synthesis in cells exposed to the sun and complementary analyzes can be performed to better define the alteration. When it comes to therapeutic strategies, currently the most used is sunlight deprivation since childhood, while other forms of management are still being studied. Conclusions: It is concluded that Xeroderma Pigmentosum is a disease of difficult control, diagnosis and management, requiring further studies on the subject and universal access to early diagnostic methods, enabling adequate prophylaxis in order to avoid future complications from the disease.

Beyond the disorders recognized as mitochondrial diseases, abnormalities in function and/or ultrastructure of mitochondria have been reported in several unrelated pathologies. These encompass ageing, malformations, and a number of genetic or acquired diseases, as diabetes and cardiologic, haematologic, organ-specific (e.g., eye or liver), neurologic and psychiatric, autoimmune, and dermatologic disorders. The mechanistic grounds for mitochondrial dysfunction (MDF) along with the occurrence of oxidative stress (OS) have been investigated within the pathogenesis of individual disorders or in groups of interrelated disorders. We attempt to review broad-ranging pathologies that involve mitochondrial-specific deficiencies or rely on cytosol-derived prooxidant states or on autoimmune-induced mitochondrial damage. The established knowledge in these subjects warrants studies aimed at elucidating several open questions that are highlighted in the present review. The relevance of OS and MDF i...

DNA damage has been long recognized as causal factor for cancer development. When erroneous DNA repair leads to mutations or chromosomal aberrations affecting onco-genes and tumor suppressor genes, cells undergo malignant transformation resulting in cancerous growth. Genetic defects can predispose to cancer: mutations in distinct DNA repair systems elevate the susceptibility to various cancer types. However, DNA damage not only comprises a root cause for cancer development but also continues to provide an important avenue for chemo-and radiotherapy. Since the beginning of cancer therapy, genotoxic agents that trigger DNA damage checkpoints have been applied to halt the growth and trigger the apoptotic demise of cancer cells. We provide an overview about the involvement of DNA repair systems in cancer prevention and the classes of genotoxins that are commonly used for the treatment of cancer. A better understanding of the roles and interactions of the highly complex DNA repair machineries will lead to important improvements in cancer therapy.

Basal cell carcinoma (BCC) is the commonest cancer in humans. Predisposing factors reflect common genetic variations and environmental influences in most cases. However, an underlying Mendelian disorder should be suspected in a specific subset of patients, namely those with multiple, early onset lesions. Some specific conditions, including Gorlin, Bazex-Dupré-Christol and Rombo syndromes, and Xeroderma Pigmentosum, show BCC as a prominent feature. In addition, BCC may represent a relatively common, although less specific, finding in many other genodermatoses. These include disorders of DNA replication/repair functions (Bloom, Werner, Rothmund-Thomson and Muir-Torre syndromes), genodermatoses affecting the folliculo-sebaceus unit (Brooke-Spiegler, Schöpf-Schulz-Passarge and Cowden syndromes), immune response (cartilage-hair hypoplasia and epidermodysplasia verruciformis) and melanin biosynthesis (oculocutaneous albinism and Hermansky-Pudlak syndrome), and some epidermal nevus syndrom...

Xeroderma pigmentosum is a rare autosomal recessive skin disorder characterized by freckle-like dry pigmented skin, photosensitivity, and photophobia. Skin and ocular symptoms are confined to sun exposed areas of the body. Patients have markedly increased risk for UV-induced skin, ocular, and oral cancers. Some patients develop neurodegenerative symptoms, including diminished tendon reflexes and microcephaly. In this study, we describe clinical and genetic findings of 36 XP patients from Egypt, a highly consanguineous population from North Africa. Thorough clinical evaluation followed by Sanger sequencing of XPA and XPC genes were done. Six novel and seven previously reported mutations were identified. Phenotype-genotype correlation was investigated. We report clinical and molecular findings consistent with previous reports of countries sharing common population structure, and geographical and historical backgrounds with implications on common ancestral origins and historical migrat...

Xeroderma Pigmentosum (XP) is a rare autosomal recessive disorder characterized by cutaneous and ocular alterations. Eight genes, Xeroderma Pigmentosum group A (XPA) to Xeroderma Pigmentosum group G (XPG) and Xeroderma Pigmentosum group V (XPV), are known to be responsible for the disease and products of these genes are involved in the repair of deoxyribonucleic acid (DNA) lesions generated by UV radiation. Several XP patients suffer from neurological defects, found in the XPA (the most common form), D and G groups. The aim of this study was to investigate the mutational spectrum of XPA in Tunisia, in order to propose a simple tool for molecular diagnosis. This study was carried out on six unrelated families with nine Tunisian XPA patients. Clinical features were recorded. As a previous study showed the presence of the R228X mutation in Tunisia, patients were first screened for this mutation by polymerase chain reaction-restriction fragment length polymorphism and then confirmed by direct sequencing. The results showed that all patients carried the XPA R228X mutation. This mutation corresponds to a C to T transition, which creates a premature stop codon at position 228, thus causing a DNA repair defect. The XPA R228X mutation is common in Tunisian population. This mutation is associated with a relatively moderate phenotype of the XPA. As all explored patients presented the recurrent mutation XPA R228X, a potential founder effect was searched and confirmed by haplotype analysis. Taking into account similar genetic background, investigation of this mutation should allow a cost effective and rapid diagnosis of XPA in north-African populations.

Xeroderma pigmentosum (XP) and Cockayne syndrome (CS) are quite distinct genetic disorders that are associated with defects in excision repair of UV-induced DNA damage. A few patients have been described previously with the clinical features of both disorders. In this paper we describe an individual in this category who has unusual cellular responses to UV light. We show that his cultured fibroblasts and lymphocytes are extremely sensitive to irradiation with UV-C, despite a level of nucleotide excision repair that is 30%-40% that of normal cells. The deficiency is assigned to the XP-D complementation group, and we have identified two causative mutations in the XPD gene: a gly-->arg change at amino acid 675 in the allele inherited from the patient's mother and a -1 frameshift at amino acid 669 in the allele inherited from his father. These mutations are in the C-terminal 20% of the 760-amino-acid XPD protein, in a region where we have recently identified several mutations in ...

Cockayne syndrome (CS) and xeroderma pigmentosum (XP) are human photosensitive diseases with mutations in the nucleotide excision repair (NER) pathway, which repairs DNA damage from UV exposure. CS is mutated in the transcription-coupled repair (TCR) branch of the NER pathway and exhibits developmental and neurological pathologies. The XP-C group of XP patients have mutations in the global genome repair (GGR) branch of the NER pathway and have a very high incidence of UV-induced skin cancer. Cultured cells from both diseases have similar sensitivity to UV-induced cytotoxicity, but CS patients have never been reported to develop cancer, although they often exhibit photosensitivity. Because cancers are associated with increased mutations, especially when initiated by DNA damage, we examined UV-induced mutagenesis in both XP-C and CS cells, using duplex sequencing for high-sensitivity mutation detection. Duplex sequencing detects rare mutagenic events, independent of selection and in m...

Benzo[a]pyrene (BaP) is a ubiquitously distributed environmental pollutant known to cause DNA damage, which may be repaired through nucleotide excision repair (NER). However, little is known about dynamic changes in levels of DNA damage and their correlations with levels of NER proteins in cells exposed to BaP. In a series of experiments using the human bronchial epithelia cells (16HBE) exposed to different concentrations of BaP for different times, we measured dynamic changes in levels of DNA damage and expression of NER subunit xeroderma pigmentosum (XP) groups A, C, F, G (XPA, XPC, XPF, XPG) and excision repair cross-complementing 1 (ERCC1), and analyzed their possible correlations. We found that in vitro exposure to BaP reduced cell viability in a dose-dependent manner ranging from 2 to 64microM and increased DNA damage in a dose- and time-dependent manner. Our results showed that levels of these NER proteins significantly increased and peaked at 12th or 24th, 8th or 12th and 4th or 8th hours in cells exposed to 2, 8 and 16microM BaP, respectively. ERCC1 expression increased by 2.4-, 4.2- and 19.3-fold for exposure to 2, 8 and 16microM BaP, respectively, compared with control group. Moreover, levels of ERCC1 in cells exposed 16microM BaP significantly higher than those in 2 and 8microM BaP from 2nd to 48th hours. In addition, there was a significant positive correlation between Olive tail moments and relative ratios of ERCC1 in cells exposed to BaP. Our results suggested ERCC1 may be an important limiting factor for NER, but the mechanisms underlying this observation needs further investigation.