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Atypical fibroxanthoma of the skin and the lower lip in xeroderma pigmentosum.

Xeroderma pigmentosum (XP) is a rare, usually autosomal recessive disorder related to DNA repair defects. Atypical fibroxanthoma (AFX) is a pleomorphic tumour that occurs infrequently on the limbs and trunk in children. We report a child with XP who presented with AFX of the facial skin and the lower lip. The diagnosis of AFX was confirmed using histological and immunohistochemical techniques. We discuss the possibility that ultraviolet-induced damage might be implicated in the pathogenesis of AFX.

Carcinoma, Squamous Cell↗

Management of xeroderma pigmentosum.

Xeroderma pigmentosum is an autosomal recessive disease associated with a defect in DNA repair from damage by ultraviolet light. It is characterized by the development of cutaneous malignancies in childhood and by death from the local or systemic complications thereof by the third decade of life. The head and the neck are the most frequently affected areas. Management involves sunlight avoidance and prompt biopsy of any new skin lesion. Due to the chronic nature of the disease, it is necessary to excise the least amount of tissue consistent with tumor removal in order to preserve skin for future procedures. In some patients, radiation therapy and/or certain chemotherapeutic agents are abnormally cytotoxic and must be utilized with caution.

Head and Neck Neoplasms↗

The treatment of basal skin carcinomas in two sisters with xeroderma pigmentosum.

Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder that causes defects in the DNA repair system. It is characterized by a marked sensitivity to sunlight, and sufferers develop serious sunburns with onset of poikilodermia in the light-exposed skin. Squamous cell carcinomas, basal cell carcinomas (BCCs) and malignant melanomas appear in childhood. Two sisters with XP presented with previously treated facial BCCs. They were treated with imiquimod 5% cream three times weekly, one for 6 weeks and the other for 10 weeks. Although both sisters temporarily discontinued treatment due to severe erythema and erosion, successful long-term clearance was observed with no recurrences in both cases.

Administration, Topical↗

[Xeroderma pigmentosum].

Xeroderma pigmentosum(XP) is an autosomal recessive disease that is characterized by hypersensitivity to sunlight with high incidence of skin cancer and that exhibit variable neurological abnormalities in some groups. There are eight different complementation groups in XP; groups A through G and a variant(XP-V). XP-A through XP-G have a defect in nucleotide excision repair(NER), while XP-V has a defect in translesion DNA synthesis. Almost all of genes for XP have been cloned and their functions in the NER mechanism have been progressively unveiled. In this review, the present knowledge of the pathological features and genetic defects in XP has been discussed.

Animals↗

[Ultrastructural findings in the cornea in xeroderma pigmentosum].

Xeroderma pigmentosum is a very rare disease caused by an inherited defect in the DNA repair system. The cells are less able to repair defects caused by UV radiation, which results in early aging of the skin and the development of malignant skin tumors. Robins assumes that the eye is involved in 60% of the cases. In our patient we found a dense opacity of both corneas in addition to the typical lentiginous alteration of the skin. Therefore, a corneal transplantation was carried out on both eyes. The corneal buttons obtained by keratoplasty were examined by light, and transmission electron microscopy. We found massive alterations in the tissues of all corneal layers.

Adult↗

[Xeroderma pigmentosum].

Xeroderma pigmentosum (XP), an autosomal recessive disorder, is characterized by extreme sensitivity to sun exposure, a high incidence of skin cancer and frequent neurological abnormalities. Cells from XP patients of seven complementation groups (A-G) have defects in the nucleotide excision repair of UV damage, whereas the defect of another type, the XP variant, is not yet known. Recent discoveries of causative genes of XP have uncovered the molecular mechanisms of nucleotide excision repair. The analysis of gene mutation in XPA gene made a diagnosis of patients and carriers quicker and easier. Further, a relationship between the type of XPA gene mutation and clinical severity has also been uncovered. By analysing skin cancers developed on XP patients, the representative of UV-induced skin cancers, the molecular bases of UV skin carcinogenesis have also been rapidly discovered.

Animals↗

HLA antigens in 16 families with xeroderma pigmentosum.

Xeroderma pigmentosum is an autosomal recessive disease. HLA-A and -B typing was performed on peripheral blood lymphocytes and platelets. Sixteen Tunisian families were typed with 37 patients and 108 relatives. Genetic transmission of the disease and of the HLA system seemed to be independent in this study. Comparison of HLA gene frequencies between (unrelated) parents of patients and a control population showed no difference, proving that there is no clear association in populations between deleterious XP genes and a particular HLA gene. However, an excess of identical HLA among pairs of diseased siblings would suggest that the disease is polymorphic and a form of the XP could be linked to HLA.

Blood Platelets↗

Xeroderma pigmentosum.

Xeroderma pigmentosum is a rare, recessively transmitted disease associated with increased sensitivity to ultraviolet radiation in wavelengths found in sunlight, development of cancers in sun-exposed areas of the body in much larger numbers and much earlier in life than in normal individuals, and in some patients, neurologic deficiencies unrelated to sun exposure. Extensive cellular, biochemical, and molecular genetic studies in numerous laboratories have revealed that cells derived from patients with this disease have defective repair of ultraviolet-light-induced damage in cellular DNA, and that extensive genetic heterogeneity and numerous distinct genes are involved in the genetics of this disease and the etiopathogenesis of its associated changes. A number of these genes and gene products are now being, or have been, cloned, and their gene products characterized.

DNA↗

hRAD30 mutations in the variant form of xeroderma pigmentosum.

Xeroderma pigmentosum (XP) is an autosomal recessive disease characterized by a high incidence of skin cancers. Yeast RAD30 encodes a DNA polymerase involved in the error-free bypass of ultraviolet (UV) damage. Here it is shown that XP variant (XP-V) cell lines harbor nonsense or frameshift mutations in hRAD30, the human counterpart of yeast RAD30. Of the eight mutations identified, seven would result in a severely truncated hRad30 protein. These results indicate that defects in hRAD30 cause XP-V, and they suggest that error-free replication of UV lesions by hRad30 plays an important role in minimizing the incidence of sunlight-induced skin cancers.

Alleles↗

Evidence that lack of deoxyribonucleic acid repair causes death of neurons in xeroderma pigmentosum.

Xeroderma pigmentosum (XP) is an autosomal recessive disorder with hypersensitivity to the lethal effects of ultraviolet radiation caused by inherited defects in deoxyribonucleic acid (DNA) repair processes. Some patients with XP develop a primary neuronal degeneration which has been thought to result from unrepaired damage in neuronal DNA. Five years ago we reported that cultured skin fibroblasts from a 12-year-old girl with XP, who then had only one major neurological abnormality of the disease, had a sensitivity to ultraviolet radiation intermediate between that of XP patients with numerous neurological abnormalities and those with none. Recent neurological studies reveal that she has a slowly but progressively developing sensorineural deafness as well as cerebellar and motor dysfunction typical of XP. The results support the postulate that defective DNA repair is associated with premature neuron death.

Adolescent↗

Effect of isotretinoin therapy on natural killer cell activity in patients with xeroderma pigmentosum.

Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder characterized by sun sensitivity, defective DNA repair, markedly increased susceptibility to skin cancer, and a variety of immunological defects, including defective natural killer (NK) cell activity. Retinoid therapy has been demonstrated to protect effectively against the development of skin cancers in patients with XP, although its mechanism of action is unknown. We describe a series of eight XP patients, six of whom were given oral isotretinoin. The NK cell activity was not affected by low-dose isotretinoin, i.e. 0.5 mg/kg per day. However, higher doses of isotretinoin, e.g. 1.0 mg/kg per day, produced a significant decrease in NK cell function, at the same time as producing a reduction in the frequency of development of skin cancers. Retinoid therapy may have a skin cancer preventing effect by enhancing other immune effector mechanisms or via epithelial cell differentiation.

Adolescent↗

Molecular cytogenetic parameters in fibroblasts from patients and carriers of xeroderma pigmentosum.

Xeroderma pigmentosum (XP) is a rare autosomal recessive syndrome. Laboratory investigations have failed to detect any consistent anomaly in cells from XP heterozygotic subjects, although examples of behavior intermediate between normal and XP cells have been reported. To estimate random aneuploidy we applied fluorescence in situ hybridization (FISH) with alpha-satellite probes for chromosomes 8 and 9 and replication pattern for TP53 (p53), ERBB2 (HER-2/neu), and MYCN (N-MYC) loci and for the imprinted SNRPN locus. A significantly higher rate of aneuploidy rate was observed in XP patients and carriers than in controls. The asynchrony pattern was significantly higher in XP carriers and patients with all three coding loci analyzed and significantly lower in XP patients and carriers with the imprinted locus SNRPN than in the control group. Molecular cytogenetic parameters such as random aneuploidy and replication pattern, which are known to reflect chromosomal instability, may be part of the tumorigenesis process. In XP patients and carriers, this genetic instability may represent a potential for developing malignancies.

Aneuploidy↗

[Anesthetic management of a patient with xeroderma pigmentosum].

Xeroderma pigmentosum (XP) is a rare autosomal recessive disease, which is characterized by hypersensitivity of the skin to ultraviolet (UV)-radiation and progressive neurological complications. Patients with XP show a failure to properly repair UV-induced DNA lesions by the nucleotide excision repair (NER) mechanism. This results predominantly in a high frequency of UV-induced skin tumors at an early age. Therefore, patients with XP must avoid exposure to UV-radiation by use of protective clothing, sunscreen and UV-blocking film. We report a 15-year-old girl, who underwent surgical treatment twice for clubfoot under general anesthesia using propofol and fentanyl. We protected her skin from light with UV blocking film in the operating room. Both surgical procedures were performed uneventfully except for delayed awakening. A number of precautions must be taken in the perioperative management of XP patients, which include proper shielding from damaging light, avoidance of all drugs that harm DNA such as halothane and careful evaluation of neurological abnormalities. There is a possibility of difficult endotracheal intubation or prolonged effect of muscle relaxation due to skin atrophy and joint contracture.

Adolescent↗

[Progress of research on xeroderma pigmentosum].

Xeroderma pigmentosum (XP) is an autosomal recessive human disease, clinically characterized by high incidence of skin cancers on sun-exposed areas. XP cells are hypersensitive to killing by ultraviolet light (UV), because they have a defect in DNA excision repair of UV-induced DNA damages. Genetic complementation analysis by cell fusion has identified 9 genetic complementation groups, designated groups A through H and a variant. However, the genetic basis of the physiological defect of XP has not yet been characterized. Recently, XP genes and human DNA repair genes have been molecularly cloned by DNA transfection methods. Molecular biological analysis of these genes should be a clue to elucidating the molecular mechanism of DNA repair in human. Moreover, an in vivo microinjection system and an in vitro system for study of DNA repair synthesis promoted by human cell extract have been developed and they can be utilized as assays during the purification of protein factors that complement repair defective XP cells. A nuclear factor that binds to DNA lesion has been identified and it was defective in group E XP cells. Yeast homolog of this nuclear factor appears to be a photolyase.

Animals↗

DNA cross-linked by cisplatin: a new probe for the DNA repair defect in xeroderma pigmentosum.

Xeroderma pigmentosum (XP) is an inherited disease characterized by the defective repair of DNA damaged by ultraviolet radiation and a number of chemicals. In this paper, plasmid DNA carrying a marker gene is cross-linked in vitro by the antitumor drug cisplatin and successfully introduced into tissue culture cells by both calcium phosphate coprecipitation and electroporation. Transient expression of the marker gene is greatly decreased in XP cells compared to wild-type. As few as seven lesions will inactivate the marker gene in XP cells. Furthermore, the biochemical defect must include an impaired capacity for repair of cisplatin-DNA intrastrand cross-links. Since the host cell itself is not exposed to chemical modification, a cisplatin cross-linked plasmid shuttle vector can be used as a specific probe for the DNA repair capacity of cultured cells. Paradoxically, when cisplatin cross-linked plasmid carrying the selectable marker neo is introduced into cells, there is an increase in the number of stable neo+ transformants in both XP and wild-type cells. Thus, cisplatin damage appears to stimulate the integration of transfected DNA into the host chromosome by a mechanism that is independent of the defective repair pathway in XP.

Cell Line↗

Identical mutations in the CSB gene associated with either Cockayne syndrome or the DeSanctis-cacchione variant of xeroderma pigmentosum.

Xeroderma pigmentosum (XP) and Cockayne syndrome (CS) are two hereditary disorders in which photosensitivity is associated with distinct clinical and cellular phenotypes and results from genetically different defects. We have identified the primary molecular alteration in two patients in whom clinical manifestations strongly reminiscent of a severe form of XP were unexpectedly associated with the CS cellular phenotype and with a defect in the CSB gene. Sequencing of the CSB -coding region in both cDNA and genomic DNA showed that these patients had identical alterations to those in a patient with the clinical features of the classical form of CS. These data, together with fluorescence in situ hybridization analysis, demonstrated that the two siblings with XP as well as the CS patient were homozygous for the same CSB mutated allele, containing a silent C2830T change and a nonsense mutation C2282T converting Arg735 to a stop codon. The finding that the same inactivating mutation underlies different pathological phenotypes indicates that there is no simple correlation between the molecular defect and the clinical features. Therefore, alterations in the CSB gene give rise to the same repair defect at the cellular level but other genetic and/or environmental factors determine the pathological phenotype.

Cells, Cultured↗

Impaired interferon production and natural killer cell activation in patients with the skin cancer-prone disorder, xeroderma pigmentosum.

Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder with sun sensitivity, markedly increased skin cancer susceptibility, and defective DNA repair without consistently identified symptoms of immune deficiency. We examined natural killer (NK) cell activity and interferon production in peripheral blood lymphocytes (PBL) of eight XP patients who had multiple primary skin cancers. The XP patients had normal numbers of T cells and NK cells, as well as normal lymphokine-activated killer cell activity and normal tumor necrosis factor-alpha production. Unstimulated NK cell function was 40% of normal controls in five XP patients, but was normal in three other XP patients. However, PBL from all the XP patients tested showed no enhancement of NK activity by the interferon inducer, polyinosinic acid:polycytidilic acid (polyIC) but enhancement by interferon-alpha was normal, suggesting an impairment in interferon production. Parallel studies in non-XP skin cancer patients revealed that both unstimulated and polyIC-enhanced NK activity were normal. Further investigation using PBL from XP patients revealed that the production of interferon-gamma after stimulation with interferon inducers (polyIC, interleukin 2, or K562 tumor cells) was 13-43% of normals. These data indicate that XP lymphocytes have a defect in production of interferons and suggest that defective interferon production, as well as DNA repair defects, may play an important role in the susceptibility of XP patients to skin cancer.

Adolescent↗

[Carcinoma of the tongue in xeroderma pigmentosum].

Xeroderma pigmentosum (XP) is a rare genodermatosis characterized by a defect in the repair of DNA damage induced by ultraviolet rays. The cutaneous tumours are frequent and occur at an early age, but neoplasias of the mucosae are seldom observed. Among the mucosae, the lipids and the conjunctiva clearly predominate. Tumours of the buccal cavity are much less frequent, and this is why we report a case of epidermoid carcinoma of the tip of the tongue in a Moroccan boy. Only 25 cases of intrabuccal tumour have been reported in patients with XP, and 22 were epidermoid carcinomas of the tip of the tongue. These carcinomas may be preceded by precancerous lesions such as leucoplasia. The early occurrence and elective location at the tip of the tongue clearly differentiate lingual carcinomas associated with XP from their homologues in adults. The aggressiveness of these lesions is difficult to determine due to a usually short follow-up and to the lack of details in reports. Treatment is surgical and non-specific. Concerning epidemiology, the predominance of African and Near-Eastern patients among those suffering from lingual carcinoma is striking. Moreover, when the complementation group is known it is always group C; our patients presented with characteristics of this group. Some authors believe that the lingual tumours are due to ultraviolet light (overexposure in case of natural pigmentation, with exposure of the tip of the tongue) and to certain toxic substances in food.(ABSTRACT TRUNCATED AT 250 WORDS)

Basal Cell Carcinoma↗