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.

Oral mucosa involvement in pediatric patients with xeroderma pigmentosum: a comprehensive review

BACKGROUND

Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder presenting with an inability to repair UV-induced DNA damage. This can lead to the development of neoplasms affecting multiple organ systems, with onset often in childhood. Unfortunately, no cure currently exists for XP, and management strategies focus on sun protection and early intervention for malignancies. Although most skin problems in XP patients are UV induced, various oral lesions are also described. However, the literature has not extensively characterized the oral manifestations and their prognostic significance.

METHODS

We conducted a comprehensive review to evaluate the prevalence and nature of oral mucosal lesions in pediatric XP patients.

RESULTS

Our literature search yielded 130 pediatric XP patients with oral involvement and 210 associated tumoral or non-tumoral lesions. Squamous cell carcinoma was the most common type of oral mucosal tumor reported, with other malignancies including basal cell carcinoma, melanoma, angiosarcoma, fibrosarcoma, and trichilemmal carcinoma.

CONCLUSION

Given the potential morbidity and mortality associated with oral mucosal tumors in XP patients, our study aims to raise awareness of these manifestations. Early diagnosis and treatment are crucial for managing these lesions effectively, and routine oral exams should be considered a critical component of dermatological evaluations for XP patients, especially in the pediatric age group.

Xeroderma pigmentosum group G with pellagroid rash: A rare presentation

Xeroderma pigmentosum (XP), a heterogeneous genodermatoses, has a variable clinical spectrum ranging from mild freckling and photosensitivity to severe skeletal and neurological abnormalities and cutaneous malignancies. Herein, we present the case of a 4-year-old boy with XP group G who presented with a pellagroid rash.

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

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

SNP Array Screening and Long Range PCR-Based Targeted Next Generation Sequencing for Autosomal Recessive Disease with Consanguinity: Insight from a Case of Xeroderma Pigmentosum Group C

Advances in genetic technologies have made genetic testing more accessible than ever before. However, depending on national, regional, legal, and health insurance circumstances, testing procedures may still need to be streamlined in real-world clinical practice. In cases of autosomal recessive disease with consanguinity, the mutation locus is necessarily isodisomy because both alleles originate from a common ancestral chromosome. Based on this premise, we implemented integrated genetic diagnostic methods using SNP array screening and long range PCR-based targeted NGS in a Japanese patient with xeroderma pigmentosum (XP) under the limitation of the national health insurance system. SNP array results showed isodisomy only in XPC and ERCC4 loci. NGS, with a minimal set of long-range PCR primers, detected a homozygous frameshift mutation in XPC; NM_004628.5:c.218_219insT p.(Lys73AsnfsTer9), confirmed by Sanger sequencing, leading to a rapid diagnosis of XP group C. This shortcut strategy is applicable to all autosomal recessive diseases caused by consanguineous marriages, especially in scenarios with a moderate number of genes to test, a common occurrence in clinical genetic practice.

Multiple Facial Basal Cell Carcinoma With Xeroderma Pigmentosum

Multiple basal cell carcinomas are rare in children and adolescents. Xeroderma pigmentosum (XP) is a rare autosomal recessive hereditary disease characterized by photosensitivity, changes in skin pigmentation, and early onset of skin cancer. XP is extremely rare in clinical practice, with only a few cases worldwide. XP is clinically incurable. The main goal of treating this disease is to diagnose as early as possible, educate patients to strictly avoid ultraviolet radiation for life, and follow up regularly to treat skin malignant tumors in time. The authors report a 15-year-old boy with facial multiple basal cell carcinoma with XP. Its medical history, clinical features, auxiliary examination, and surgical treatment process have great reference value for the in-depth understanding of the disease. The authors will discuss how to delay the progression of the disease and treat the existing lesions in different clinical stages of the disease in combination with the existing relevant literature.

Cutaneous Neurocristic Hamartoma Mimicking Basal Cell Carcinoma in a Patient With Xeroderma Pigmentosum

ABSTRACT

Neurocristic hamartomas (NCH) of cutaneous origin are especially rare congenital or acquired neoplasms that often arise through aberrant embryologic development of pluripotent neural crest cells. Clinically, they often present as pigmented macules or papules on the scalp with associated alopecia. NCHs are characterized histopathologically by dermal melanocytic, fibroblastic, and neurosustentacular components. Correct identification of this etiology is critical because of potential for malignant transformation, particularly in acquired NCHs. Our patient was a 6-year-old girl with xeroderma pigmentosum and confirmed XPC mutation followed in our dermatology clinic since the age of 3. She had a history of multiple actinic keratoses but no prior skin cancers. A 4-mm homogenous pink papule on the left frontal scalp concerning for basal cell carcinoma was noted during routine skin examination. After a 3-month course of 3 times weekly topical imiquimod, the lesion had grown to a 6 mm diameter. The patient was then referred to plastic surgery for definitive excision. Histologically, the lesion showed a well-circumscribed proliferation of spindle cells with a trabecular and nested growth pattern. Perivascular pseudorosettes were identified, as were areas that resembled well-differentiated neural tissue. The spindle cells diffusely expressed S100 protein, SOX10, and CD34, with patchy expression of Melan-A and HMB-45. PRAME was negative, and p16 was retained. Array comparative genomic hybridization was performed, and no clinically significant copy number or single nucleotide variants were detected. To the best of our knowledge, this is the first documented case in the literature of a cutaneous neurocristic hamartoma arising in a patient with xeroderma pigmentosum.

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

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

A novel missense variant and multiexon deletion causing a delayed presentation of xeroderma pigmentosum, group C

Pathogenic variants in the XPC complex subunit, DNA damage recognition, and repair factor (XPC) are the cause of xeroderma pigmentosum, group C (MIM: 278720). Xeroderma pigmentosum is an inherited condition characterized by hypersensitivity to ultraviolet (UV) irradiation and increased risk of skin cancer due to a defect in nucleotide excision repair (NER). Here we describe an individual with a novel missense variant and deletion of exons 14-15 in XPC presenting with a history of recurrent melanomas. The proband is a 39-yr-old female evaluated through the Mayo Clinic Department of Clinical Genomics. Prior to age 36, she had more than 60 skin biopsies that showed dysplastic nevi, many of which had atypia. At age 36 she presented with her first melanoma in situ, and since then has had more than 10 melanomas. The proband underwent research whole-exome sequencing (WES) through the Mayo Clinic's Center for Individualized Medicine and a novel heterozygous variant of uncertain significance (VUS) in XPC (c.1709T > G, p.Val570Gly) was identified. Clinical confirmation pursued via XPC gene sequencing and deletion/duplication analysis of XPC revealed a pathogenic heterozygous deletion of ∼1 kb within XPC, including exons 14 and 15. Research studies determined the alterations to be in trans Although variants in XPC generally result in early-onset skin cancer in childhood, the proband is atypical in that she did not present with her first melanoma until age 36. Review of the patient's clinical, pathological, and genetic findings points to a diagnosis of delayed presentation of xeroderma pigmentosum.

Xeroderma Pigmentosum - Cockayne Syndrome Complex (XP-CS) - Another case

We present the case of a 3-year old girl with clinical manifestations typical of XP-CS, an extremely rare combination of Xeroderma Pigmentosum and Cockayne Syndrome. She had a swelling above the upper lip and multiple brown spots on her face, neck, arms and back. She was globally delayed, deaf, dumb and photophobic. MRI brain showed mild cerebral atrophy and bilateral demyelination. De Sanctis Cacchione variant (dSCS) and Rothmund Thomson syndrome (RTS), which were among the differential diagnosis were ruled out upon careful evaluation. Supportive treatment was given and regular checkups were recommended to monitor the progression of the disease but our patient did not show up for the follow up. This report shows that the diagnosis of XP-CS can be based on clinical features and MRI findings when the genetic testing is not available.

Recommendations for Childhood Cancer Screening and Surveillance in DNA Repair Disorders

DNA repair syndromes are heterogeneous disorders caused by pathogenic variants in genes encoding proteins key in DNA replication and/or the cellular response to DNA damage. The majority of these syndromes are inherited in an autosomal-recessive manner, but autosomal-dominant and X-linked recessive disorders also exist. The clinical features of patients with DNA repair syndromes are highly varied and dependent on the underlying genetic cause. Notably, all patients have elevated risks of syndrome-associated cancers, and many of these cancers present in childhood. Although it is clear that the risk of cancer is increased, there are limited data defining the true incidence of cancer and almost no evidence-based approaches to cancer surveillance in patients with DNA repair disorders. This article is the product of the October 2016 AACR Childhood Cancer Predisposition Workshop, which brought together experts from around the world to discuss and develop cancer surveillance guidelines for children with cancer-prone disorders. Herein, we focus on the more common of the rare DNA repair disorders: ataxia telangiectasia, Bloom syndrome, Fanconi anemia, dyskeratosis congenita, Nijmegen breakage syndrome, Rothmund-Thomson syndrome, and Xeroderma pigmentosum. Dedicated syndrome registries and a combination of basic science and clinical research have led to important insights into the underlying biology of these disorders. Given the rarity of these disorders, it is recommended that centralized centers of excellence be involved directly or through consultation in caring for patients with heritable DNA repair syndromes. Clin Cancer Res; 23(11); e23-e31. ©2017 AACRSee all articles in the online-only CCR Pediatric Oncology Series.

[Multiple facial squamous cell carcinomas in a child, revealing a xeroderma pigmentosum]

BACKGROUND

Squamous cell carcinoma of the skin is very rare in children. One of its most common risk factors is xeroderma pigmentosum (XP), an autosomal recessive disease characterized by defective cellular DNA repair, and hypersensitivity to ultraviolet radiation.

CASE REPORT

We report a case of XP in a 7-year-old black African boy, revealed by squamous cell carcinomas of the inferior lip and upper left eyelid.

DISCUSSION

In sub-Saharan regions, the early diagnosis of XP is difficult because of its uncommon occurrence on black skin and black skin specificities. The strong sun radiation in the tropics and a late diagnosis make XP treatment challenging. Thus, prevention in patients' families is mandatory.

Xeroderma pigmentosum: a case report and review of the literature

Inherited molecular defects in nucleotide excision repair genes cause the autosomal recessive condition xeroderma pigmentosum. Xeroderma pigmentosum is characterized by photo-hypersensitivity of sun-exposed tissues, and by a several thousand-fold increase in the risk of developing malignant neoplasms of the skin and of the eyes. Mutations in xeroderma pigmentosum genes that regulate nucleotide excision repair, not only predispose persons with xeroderma pigmentosum to multiple malignancies, but also promote premature cutaneous and ocular ageing, and in some cases promote progressive neurodegenerative changes. This paper describes a case of xeroderma pigmentosum with advanced cutaneous squamous cell carcinoma, actinic cheilitis and ocular lesions in a 19-year-old black woman. The extensive ultraviolet radiation-induced skin and eye damage are evidence of neglect of sun-protection and lack of appropriate medical care from childhood.

[Photosensitive disorders--focusing on photosensitive genetic diseases]

Among various photosensitive disorders, photosensitive genetic diseases are noticeable in that physicians play a key role in early diagnosis. Xeroderma pigmentosum (XP) and erythropoetic protoporphyria (EPP) are focused on this issue as photosensitive genetic diseases. XP is characterized by the proneness to skin cancers of sun-exposed area from younger age. XP-A through G and XP-V are caused by the deficiency in nucleotide excision repair (NER) and by translesional synthesis, respectively. NER is closely related to the transcription and the neurological features developed in some XP patients are attributed to the transcription abnormalities. As for EPP, it was shown that the combination of mutation in FECH in one allele and the low expression type SNP in the other allele cause the apparent clinical phenotype.

The versatile DNA nucleotide excision repair (NER) and its medical significance

Two of DNA's worst enemies, ultraviolet light and chemical carcinogens, can cause damage to the molecule by mutating individual nucleotides or changing its physical structure. In most cases, genomic integrity is restored by specialized suites of proteins dedicated to repairing specific types of injuries. One restoration mechanism, called nucleotide excision repair (NER), recruits and coordinates the services of 20-30 proteins to recognize and remove structure-impairing lesions, including those induced by ultraviolet (UV) light. Mutations in a gene that encodes a protein from the NER machinery might cause a wide variety of rare inherited human disorders. Sun sensitivity, cancer, developmental retardation, neurodegeneration and premature aging characterize these syndromes. Identification of the causative genes and proteins in affected families in Israel allowed us to establish accurate molecular diagnosis of couples at risk, and provide them with better genetic counseling.

Clinical implications of the basic defects in Cockayne syndrome and xeroderma pigmentosum and the DNA lesions responsible for cancer, neurodegeneration and aging

Cancer, aging, and neurodegeneration are all associated with DNA damage and repair in complex fashions. Aging appears to be a cell and tissue-wide process linked to the insulin-dependent pathway in several DNA repair deficient disorders, especially in mice. Cancer and neurodegeneration appear to have complementary relationships to DNA damage and repair. Cancer arises from surviving cells, or even stem cells, that have down-regulated many pathways, including apoptosis, that regulate genomic stability in a multi-step process. Neurodegeneration however occurs in nondividing neurons in which the persistence of apoptosis in response to reactive oxygen species is, itself, pathological. Questions that remain open concern: sources and chemical nature of naturally occurring DNA damaging agents, especially whether mitochondria are the true source; the target tissues for DNA damage and repair; do the human DNA repair deficient diseases delineate specific pathways of DNA damage relevant to clinical outcomes; if naturally occurring reactive oxygen species are pathological in human repair deficient disease, would anti-oxidants or anti-apoptotic agents be feasible therapeutic agent?

Genodermatoses with malignant potential

PURPOSE OF REVIEW

The delineation of syndromes carrying a predisposition to malignancy has led to great insights into the molecular biology of malignancy. Many such syndromes have cutaneous findings which can precede the development of neoplasia. Early recognition of the cutaneous stigmata of the genodermatoses with malignant potential can lead to early diagnosis and initiation of proper screening and treatment when indicated.

RECENT FINDINGS

This article reviews 'classic' genodermatoses with malignant potential and highlights recent recommendations for screening and treatment. Additionally more recently delineated syndromes and their cutaneous findings are discussed.

SUMMARY

Certain inherited syndromes with a risk of neoplasia exhibit characteristic cutaneous findings. Recognition of these findings by the astute practitioner can lead to early intervention which can impact the course of these rare diseases.

Xeroderma pigmentosum: beyond skin cancer

Xeroderma pigmentosum (XP) is a rare, autosomal-recessive inherited disease that is found worldwide at a frequency of approximately 1:250,000. XP is caused by a deficiency in either nucleotide excision repair (NER) or postreplication repair (PRR), and is characterized by severe actinic changes leading to early onset of skin cancers, various ocular manifestations, and occasional neurological abnormalities. Diagnosis is usually made clinically and can be confirmed by unscheduled DNA synthesis. Early preventative care is the most important treatment modality. We present a review of the history, clinical manifestations, pathogenesis, diagnosis, and treatment of XP.

[Contribution of immunohistochemical detection of human herpesvirus-8 latent nuclear antigen-1 in the diagnosis of Kaposi disease]

AIMS

To study the immunohistochemical expression of HHV8 in Kaposi's lesions and in other vascular lesions and to determine the utility of this technique in differentiating between Kaposi's disease (KD) and other vascular lesions.

METHODS

Fixed, paraffin-embedded tissue sections from 25 cases of KD, 9 cases of hemangioma, 2 cases of angiolymphoid hyperplasia with eosinophilia and 9 cases of angiosarcoma were examined immunohistochemically using the monoclonal antibody monoclonal LNA 53 (ABI). Strong, nuclear and granular staining in at least a cell was considered as a positive result.

RESULTS

Sixteen cases of KD showed positive staining, whereas all cases of hemangioma, angiolymphoid hyperplasia with eosinophilia and angiosarcoma were negative for this antigen

CONCLUSION

Immunohistochemical detection of the human herpesvirus-8 latent nuclear antigen-1 is a useful for differentiating between KD and other vascular lesions.

Prenatal diagnosis of xeroderma pigmentosum and trichothiodystrophy in 76 pregnancies at risk

OBJECTIVE

Evaluation of results in a consecutive series of 76 prenatal diagnoses for xeroderma pigmentosum (XP) and trichothiodystrophy (TTD) made since 1977.

METHODS

UV-induced DNA repair synthesis was assessed by the autoradiographic measurement of the incorporation of (3)H-thymidine.

RESULTS

XP was diagnosed in 19 of the 76 investigated pregnancies at risk; cultured chorionic villus (CV) cells were used in 33 pregnancies with ten affected fetuses and cultured amniocytes in 43 pregnancies with nine affected fetuses. In four cases, CVS results were corroborated by subsequent investigation of amniocytes because maternal cell contamination in the CV cell culture was either present or could not be excluded. Uncertain results in two other cases with intermediate DNA repair capacity and severe maternal cell contamination required further investigation. Median time needed for cell culture and analysis was 25 days. To reduce intra-assay variations, a modification of the DNA repair synthesis assay has recently been developed. In this assay, patients and controls are investigated simultaneously in mixed cultures of cells labelled with polystyrene beads.

CONCLUSION

Reliable prenatal diagnosis for XP and TTD can be made by the demonstration of clearly reduced UV-induced DNA repair synthesis due to defective global genome nucleotide excision repair.

Aggravation of Eyelid and Conjunctival Malignancies Following Photodynamic Therapy in DeSanctis-Cacchione Syndrome

A 5-year-old girl with DeSanctis-Cacchione syndrome (a severe variant of xeroderma pigmentosum) was referred for evaluation of multiple eyelid and bulbar conjunctival squamous cell carcinomas. Examination evidenced multiple vegetating lesions on the eyelid, bulbar conjunctiva, and cornea of both eyes. As the lesions were considered not to be manageable by surgical excision and would have required exenteration, photodynamic therapy was performed on the patient's left eye. Three months after photodynamic therapy, the patient presented with a dramatic increase in the extension of the tumors. Since xeroderma pigmentosum is a DNA repair disorder, the radiation involved in photodynamic therapy probably played an iatrogenic role in the evolution of the case. We believe that photodynamic therapy may be harmful to patients with DNA repair disorders.

A novel XPC pathogenic variant detected in archival material from a patient diagnosed with Xeroderma Pigmentosum: a case report and review of the genetic variants reported in XPC

The disease Xeroderma Pigmentosum (XP) is genetically heterogeneous and defined by pathogenic variants (formerly termed mutations) in any of eight different genes. Pathogenic variants in the XPC gene are the most commonly observed in US patients. Moreover, pathogenic variants in just four of the genes, XPA, XPC, XPD/ERCC2 and XPV/POLH account for 91% of all XP cases worldwide. In the current study, we describe the clinical, histopathologic, molecular genetic, and pathophysiological features of a 19-year-old female patient clinically diagnosed with XP as an infant. Analysis of archival material reveals a novel variation of a 13 base pair deletion in XPC exon 14 and a previously reported A>C missense pathogenic variant in the proximal splice site for XPC exon 6. Both variations induce frameshifts most likely leading to a truncated XPC protein product. Quantitative RT-PCR also revealed reduced mRNA levels in the archived specimen. Analysis of the XPA, XPD/ERCC2 and XPV/POLH genes in the current specimen failed to reveal pathologic variants. All previously reported pathogenic variants, polymorphisms and known amino acid changes for the XPC gene are compiled and described in the current nomenclature. Given the relative ease of screening for genetic variation and the potential role for such variation in human disease, a proposal for screening appropriate archival materials for alterations in the four most prevalent XP genes is presented.

[De Sanctis-Cacchione syndrome]

We present a male patient with photosensitivity since the earliest months of his life, and pigmented macules in exposed areas, some showing clinical atypia, which increased in number over time. Molecular biology studies detected an alteration in DNA repair ability, so xeroderma pigmentosum was diagnosed. Shortly after birth, low weight, microcephaly and psychomotor retardation had been observed, but the cause was not established. The patient progressively showed neurological disorders that included perceptive deafness, hyporeflexia and areflexia, as well as choreoathetotic movements. Therefore, we felt that the patient's symptoms fit De Sanctis-Cacchione syndrome.

Xeroderma pigmentosum group E and DDB2, a smaller subunit of damage-specific DNA binding protein: Proposed classification of xeroderma pigmentosum, Cockayne syndrome, and ultraviolet-sensitive syndrome

Xeroderma pigmentosum is a rare photosensitive syndrome that comprises eight different genetic diseases (A to G; variant (V)). Although genotype-phenotype correlations have been evaluated in most XP groups, the relationship between the E subgroup of xeroderma pigmentosum (XP-E) and damage-specific DNA binding protein (DDB) still remained a mystery. Recent studies have provided new insight for XP-E and the role(s) of DDB2, a smaller subunit of DDB. Reclassification studies have confirmed that mutations in DDB2 give rise to XP-E. The mouse model of XP-E demonstrated that DDB2 was well conserved between mouse and human and was critical in controlling proper cell-survival through regulating the tumor suppressor p53-mediated responses after ultraviolet (UV)-irradiation: i.e. defective DDB2 causes the resistance to cell-killing by UV-irradiation due to decreased p53-mediated apoptosis. These phenotypes are unique to XP-E because other XP groups show normal (XP-V) or hypersensitivity (XP-A, B, C, D, F, and G) to UV-irradiation. Thus XP-E is defined as a skin cancer prone disease with unique resistance to UV-irradiation.

Pigmented xerodermoid--report of three cases

Pigmented xerodermoid, a rare genodermatosis, presents with clinical features and pathology similar to xeroderma pigmentosum, but at a later age. DNA repair replication is normal, but there is total depression of DNA synthesis after exposure to UV radiation. Two siblings in their teens and a man in his thirties with features of pigmented xerodermoid, e.g. photophobia, freckle-like lesions, keratoses, dryness of skin, and hypo- and hyper-pigmentation, are described. Although classically the onset of pigmented xerodermoid is said to be delayed till third to fourth decade of life, it seems the disease may appear earlier in the tropics. Early diagnosis and management could be life-saving.

Two new XPD patients compound heterozygous for the same mutation demonstrate diverse clinical features

Xeroderma pigmentosum (XP) and Cockayne syndrome (CS) are both rare autosomal recessive disorders with defects in DNA repair. They are usually distinct both clinically and genetically but in rare cases, patients exhibit the clinical characteristics of both diseases concurrently. We report two new phenotypically distinct cases of XP with additional features of CS (xeroderma pigmentosum and Cockayne syndrome crossover syndrome (XP/CS)) carrying an identical mutation (G47R) in the XPD gene within the N terminus of the protein. Both patients had clinical features of XP and CS but only one fulfilled most criteria for diagnosing CS. Unusually, patient 1 developed early skin cancer, in contrast to patient 2, who never developed any malignancies. Cells from both these patients have repair defects typical of xeroderma pigmentosum complementation group D (XPD) cells, but also had the phenotype of uncontrolled DNA breakage found specifically in XPD/CS cells and similarly reduced levels of TFIIH. Despite these similarities between our two patients, their clinical features are quite different and the clinical severity correlates with other cellular responses to ultraviolet irradiation.

DNA-based diagnosis of xeroderma pigmentosum group C by Whole-genome scan using single-nucleotide polymorphism microarray

In this study, we have established the molecular basis of xeroderma pigmentosum (XP) in two unrelated Chinese families. In the first patient with consanguineous parents, we mapped the disease-causing locus XPC using single-nucleotide polymorphism microarray. Mutational analysis of the XPC gene showed that the patient is homozygous for a nonsense mutation, E149X. After developing DNA-based diagnosis of XPC, we screened another XP patient for XPC mutations. We found that the second patient is a compound heterozygote of 1209delG and Q554X in this gene. These are the first XPC-causing mutations identified in Chinese patients.

Definition of a short region of XPG necessary for TFIIH interaction and stable recruitment to sites of UV damage

XPG is the human endonuclease that cuts 3' to DNA lesions during nucleotide excision repair. Missense mutations in XPG can lead to xeroderma pigmentosum (XP), whereas truncated or unstable XPG proteins cause Cockayne syndrome (CS), normally yielding life spans of <7 years. One XP-G individual who had advanced XP/CS symptoms at 28 years has been identified. The genetic, biochemical, and cellular defects in this remarkable case provide insight into the onset of XP and CS, and they reveal a previously unrecognized property of XPG. Both of this individual's XPG alleles produce a severely truncated protein, but an infrequent alternative splice generates an XPG protein lacking seven internal amino acids, which can account for his very slight cellular UV resistance. Deletion of XPG amino acids 225 to 231 does not abolish structure-specific endonuclease activity. Instead, this region is essential for interaction with TFIIH and for the stable recruitment of XPG to sites of local UV damage after the prior recruitment of TFIIH. These results define a new functional domain of XPG, and they demonstrate that recruitment of DNA repair proteins to sites of damage does not necessarily lead to productive repair reactions. This observation has potential implications that extend beyond nucleotide excision repair.

Xeroderma pigmentosum: from genetics to hopes and realities of cutaneous gene therapy

Xeroderma pigmentosum (XP) is a rare genodermatosis transmitted as an autosomal and recessive trait. XP patients are highly photosensitive and prone to develop skin tumours in sun-exposed areas. Biochemical and genetic studies have demonstrated that nucleotide excision repair, the most versatile DNA repair mechanism, is deficient in XP cells, leading to ultraviolet-induced hypermutagenesis and a predisposition of XP patients to cancer. Cloning of XP genes responsible for the disease, together with the poor efficacy of classical pharmacological treatments, have motivated approaches towards cutaneous gene therapy of the XP. The author's group have successfully reconstructed XP skin in vitro from XP keratinocytes and fibroblasts. More recently, the possibility to fully revert the phenotype of XP keratinocytes after retrovirus-mediated transfer of the adequate wild-type XP gene in XP keratinocytes was demonstrated. Reconstruction of genetically corrected XP skin in vitro constitutes a new hope toward cutaneous gene therapy of the XP.

DNA-based prenatal diagnosis in a Chinese family with xeroderma pigmentosum group A

BACKGROUND

Xeroderma pigmentosum (XP) is a group of autosomal recessive diseases characterized by hypersensitivity to ultraviolet rays. Among its eight complementation groups, XP group A (XPA) is the most severe type. The XPAC gene has been identified as the defective gene in XPA patients.

OBJECTIVES

To examine genomic DNA from a Chinese family with XPA, to determine the XPAC mutation and, after genetic counselling, to undertake DNA-based prenatal diagnosis in a subsequent pregnancy.

METHODS

Fetal DNA was extracted from amniotic fluid and used to amplify exon 5 of XPAC containing the potential mutation. Direct sequencing and restriction endonuclease digestion were used for prenatal diagnosis.

RESULTS

We identified a homozygous nonsense XPAC mutation of 631C-->T, which results in an R211X mutation in XPA protein, in the proband. Both her parents are heterozygous. Prenatal diagnosis demonstrated a heterozygous sequence predicting an unaffected child, and a healthy girl was born.

CONCLUSIONS

These data provide the first example of a DNA-based prenatal test for genodermatosis in China.

Life-threatening vocal cord paralysis in a patient with group A xeroderma pigmentosum

We report a 19-year-old male with group A xeroderma pigmentosum who presented life-threatening vocal cord paralysis. At 3 months of age, he became sensitive to sunlight, and at the age of 4 years he was diagnosed with group A xeroderma pigmentosum. The neurologic symptoms progressed slowly thereafter. From the age of 18 years, he reported the development of occasional episodic inspiratory stridor and dyspnea, but the cause remained unknown. At the age of 19, he had a common cold and became severely dyspneic and cyanotic. Immediate examination of the glottis upon arrival by an otorhinolaryngologist using a fibroscope indicated complete paralysis of both vocal cords, and tracheal intubation resulted in marked improvement of respiration. Tracheostomy was performed thereafter. Inspiratory stridor and dyspnea are the common symptoms in this disease, and some patients with group A xeroderma pigmentosum undergo a tracheostomy, but the pathogenesis remains unknown. To our knowledge, vocal cord paralysis has never been reported in patients with group A xeroderma pigmentosum. This case is presented to illustrate the importance of fibroscopy in the examination of vocal cords in patients with group A xeroderma pigmentosum before the development of life-threatening events.

Xeroderma Pigmentosum: Mondscheinkinder. Xeroderma Pigmentosum: Children of the Moon

Xeroderma pigmentosum is based on a genetic defect in the DNA repair system, which is diagnosed in early childhood. Xeroderma pigmentosum is a rare disorder, which is transmitted in an autosomal recessive manner. Children with xeroderma pigmentosum display hypersensitivity to ultraviolet (UV) radiation. These patients experience serious sunburns with minimal exposure and then develop poikiloderma in the sun-exposed areas. Squamous cell carcinomas, basal cell carcinomas and malignant melanomas all appear during childhood. The majority of patients do not reach adult, but die from metastatic cutaneous malignancies. Genetically, xeroderma pigmentosum is differentiated into 7 complementation groups (XP-A to XP-G) and the xeroderma pigmentosum variants (XP-V). The assignment to the specific complementation group is made by fusing of xeroderma pigmentosum fibroblasts. Xeroderma pigmentosum must be distinguished from other so-called DNA repair deficiency syndromes, including Cockayne syndrome and trichothiodystrophy. A topical DNA repair enzyme appears to be helpful. A recombinant liposomal encapsulated T4 endonuclease V repairs UV-induced cyclobutane-pyrimidine dimers. Direct curative treatment of xeroderma pigmentosum could be achieved with gene therapy in future. Transfection of an intact repair gene which specifically codes for the missing repair protein could open new possibilities in the therapy of xeroderma pigmentosum.

[Xeroderma pigmentosum and related syndromes]

Xeroderma pigmentosum, trichothiodystrophy and Cockayne-syndrome are rare, autosomal recessive genodermatoses, which are clinically heterogeneous. Generally, the first signs and symptoms appear at an early age. Although all three syndromes show photosensitivity and an underlying defect in the repair of UV-induced DNA damage, only patients with xeroderma pigmentosum have an increased skin cancer risk. The fact that all three of these syndromes can be caused by mutations in the same gene further emphasizes the role of these syndromes as an important model system for the pathogenesis of skin tumors. Recent findings in the fields of DNA repair, regulation of transcription and immunology have not only further unraveled the underlying mechanisms of these diseases but also provided important insights into the pathogenesis of skin tumors. The clinical characteristics of xeroderma pigmentosum and related DNA repair deficiencies are reviewed with an attempt to point out direct connections between clinical signs and symptoms and their underlying mechanisms.

[A whole family affected by xeroderma pigmentosum: clinical and genetic particularities]

INTRODUCTION

Xeroderma pigmentosum is a relatively frequent genodermatosis in North Africa. It is characterized by abnormal sensitivity to ultraviolet light, responsible for the early occurrence of multiple cutaneous neoplasms. We present the results of the clinical and biological investigations in a family in which all its members exhibited xeroderma pigmentosum.

PATIENTS AND METHODS

Since 1962, the father, mother, the 5 children and the maternal uncle were all followed-up in the dermatology department in Tunis for a variant of xeroderma pigmentosum. Clinical (dermatological, neurological and ophthalmologic), biological, photobiological and molecular biology investigations were carried out.

RESULTS

Diagnosis of a variant of xeroderma pigmentosum was established on the delayed appearance (after the age of 4) of poikiloderma and the early onset of multiple carcinomas, without neurological disorders. Fifty-eight squamous cell and 3 basal cell carcinomas were diagnosed and treated by surgical exeresis or radiotherapy. The third child, treated with etretinate for 6 years, had developed 38 carcinomas. Contrary to the parents, whose first carcinomas had appeared at the age of 34 and 40 years, the cutaneous cancers in the children appeared early, between the ages of 17 and 24. The minimal erythematous dose was normal in all these patients. Conversely, the phototest revealed persistent erythema and the delayed appearance of multiple dyskeratosis cells. Molecular biology confirmed the diagnosis of xeroderma pigmentosum with the presence of a low level DNA repair. The third child, the father and the uncle respectively exhibited DNA repair rates of 32, 57 and 72%, compared with normal controls. The results of the complementarity tests conducted in the third child suggested that this family belonged to the genetic F group. Discussion The clinical and molecular data confirmed the diagnosis of xeroderma pigmentosum in this family and their genetic F group profile. However, this family exhibited clinical (the cutaneous involvement was more severe in the children) and molecular heterogeneity and the level of DNA repair was high in comparison with the levels (between 12 and 15%) reported by Japanese authors in group F xeroderma pigmentosum. The third child exhibited 10-fold more carcinomas that his siblings. This high rate of carcinoma may be explained by excessive exposure to sun and/or the retinoid treatment, particularly since his DNA repair rate (32%) was relatively high compared with that of severe (0-5%) and moderate (5-15%) forms of the disease.

Xeroderma pigmentosum

Xeroderma pigmentosum is a rare disorder transmitted in an autosomal recessive manner. Xeroderma pigmentosum is based on a genetic defect in the DNA repair system. This disease manifests in early childhood. Patients with xeroderma pigmentosum have a marked sensitivity to sunlight and develop serious sunburns with onset of poikilodermia in the light-exposed skin. Squamous cell carcinomas, basal cell carcinomas and malignant melanomas already appear in childhood. The majority of patients die before reaching adulthood because of metastases. Genetically, xeroderma pigmentosum is divided into 7 complementation groups (XP-A to XP-G) and the xeroderma pigmentosum variants (XP-V). Diagnostically, assignment to the specific complementation group is made according to the fusioning of xeroderma pigmentosum fibroblasts. Differential diagnosis must distinguish xeroderma pigmentosum from other so-called DNA-repair-deficiency syndromes like the Cockayne Syndrome and trichothiodystrophy. Currently, there are reports of successful application of a topical DNA Repair Enzyme. This is a recombinant liposomal encapsulated T4 endonuclease V, which repairs UV-induced cyclobutan-pyrimidine dimers. In future, causal therapy could be based on gene therapy. The introduction of an intact repair gene which specifically codes the repair protein, could open new possibilities in the treatment of xeroderma pigmentosum.

Compound heterozygosity for the Xeroderma pigmentosum complementation group A gene associated with a mild phenotype

We describe a case of a 7-year-old boy diagnosed as xeroderma pigmentosum complementation group A (XPA). Severe photosensitivity developed at 5 months after birth, and at a visit to our hospital at the age of five years, multiple brownish freckles were present on the face. XPA complementing (XPAC) gene compensated the ability of DNA repair after UV-irradiation of the fibroblasts. PCR-RFLP and DNA sequencing analyses revealed compound heterozygosity for a splicing mutation (IV3 -1G => C) at the splicing acceptor site of intron 3 and a nonsense mutation (Arg228 => stop) in exon 6. The former mutation can be detected by a restriction enzyme Alw NI and the latter detected by Hph I. Neither obvious neurological symptoms nor malignant skin tumors were noted. This genotype is associated with milder clinical symptoms than homozygosity for the IV3 -1G => C mutation.

Neurocutaneous disorders

"Neurocutaneous disorders" is a catch-all phrase that includes all disorders involving both the nervous systems and the skin. These may range from disorders in which cutaneous findings are essential to diagnosis to those with less significant involvement of the skin. Because of the variety of disorders that involve the skin and the nervous system, this article reviews a few of the more essential diagnoses, and those with recent advancements in diagnosis and management. Many of these diseases are single gene disorders, for which the genes have been discovered in the past few years. The article is divided into sections, highlighting disorders transmitted by different inheritance pattern.

[Bronchopulmonary Kaposi's disease in 2 AIDS patients living in a zone of high tuberculosis/HIV prevalence]

The epidemic form of Kaposi's disease, called Kaposi-AIDS, was first described in 1981 by Hymmes in two young AIDS patients. Lung lesions are observed in 10 to 45% of patients with cutaneous Kaposi and are the second leading localization of visceral involvement after the digestive tract. Diagnosis and management of these visceral forms remains difficult. We report two cases of broncho-pulmonary Kaposi-AIDS in two patients treated for cutaneous Kaposi's disease. The diagnosis was made on the basis of epidemiological, clinical, biological, radiological, endoscopic, and histological evidence. The diagnosis was achieved by elimination after ruling out all other opportunistic diseases with pulmonary tropism. The fear of miliary tuberculosis remains strong in zones with a high prevalence of tuberculosis. Despite considerable improvement with antiretroviral drugs, especially antiproteases, outcome remains unpredictable with or without specific treatment.

Lentigo

A lentigo is a small pigmented macule with a sharply circumscribed border. There are multiple clinical and etiologic forms. Lentigines are often initially identified shortly after birth, although they may appear later in childhood. Certain varieties are associated with systemic abnormalities. Histologic findings include epidermal hyperplasia with increased pigmentation of the basal layer.

Xeroderma pigmentosum--bridging a gap between clinic and laboratory

Xeroderma pigmentosum (XP) is an autosomal recessive photosensitive disorder with an extremely high incidence of UV-related skin cancers associated with impaired ability to repair UV-induced DNA damage. There are seven nucleotide excision repair (NER) complementation groups (A through G) and an NER proficient form (XP variant). XPA, B, D and G patients may also develop XP neurological disease. The laboratory diagnosis of XP can be performed by autoradiography. Recently, the isolation and characterization of the genes responsible for XP have made it possible to use molecular biological techniques to diagnose XP patients, for carrier detection and for prenatal diagnosis, especially in Japanese XPA patients. These techniques include polymerase chain reaction (PCR) and plasmid host cell reactivation assays with cloned XP genes. DNA damage is not repaired by the NER system equally throughout the genome. There are two DNA repair pathways: 1) transcription-coupled repair, and 2) global genome repair. Many factors involved in these pathways are related to the pathogenesis of XP and a related photosensitive disease, Cockayne syndrome. Clinical management consists of early diagnosis followed by a rigorous program of sun protection including avoidance of unnecessary UV exposure, wearing UV blocking clothing, and use of sunblocks on the skin. Although there is no cure for XP, the efficacy of oral retinoids for the prevention of new skin cancers, local injection of interferon, and the external use of a prokaryotic DNA repair enzyme have been reported.

Useful applications of DNA repair tests for differential diagnosis of atypical dyschromatosis symmetrica hereditaria from xeroderma pigmentosum

Dyschromatosis symmetrica hereditaria (DSH) is a hereditary skin disease characterized by the presence of pigmented and hypopigmented macules on the extremities and freckles on the face. However, if clinical features are not fully developed in infantile patients, it is difficult to differentiate DSH from xeroderma pigmentosum by clinical features alone. A 2-year-old boy (patient 1), revealed atypical features of DSH with slight susceptibility to sunburn. However, his grandfather (patient 4) who was 67 years old, revealed typical features of DSH, which helped to make an exact diagnosis in patient 1. For patient 2, a 5-year-old boy, and patient 3, a 3-year-old girl, it was more difficult to make a diagnosis because there were no family members with DSH features. DNA repair ability was tested for all four cases by means of unscheduled DNA synthesis and colony formation of skin fibroblasts after ultraviolet light irradiation, which resulted in an accurate diagnosis of DSH. We propose that these tests be performed to make a diagnosis of DSH in the case of poor or atypical clinical symptoms.

Xeroderma pigmentosum variant heterozygotes show reduced levels of recovery of replicative DNA synthesis in the presence of caffeine after ultraviolet irradiation

Patients with xeroderma pigmentosum variant show clinical photosensitivity, skin neoplasias induced by ultraviolet light, and defective postreplication repair, but normal nucleotide excision repair. We recently reported an alternative, simple method for the diagnosis of xeroderma pigmentosum variant that measures by autoradiography three cellular markers for DNA repair after ultraviolet irradiation: unscheduled DNA synthesis, recovery of RNA synthesis, and recovery of replicative DNA synthesis. Among hereditary photosensitive disorders, including other xeroderma pigmentosum groups, Cockayne syndrome, and a newly established ultraviolet-sensitive syndrome, only xeroderma pigmentosum variant cells exhibited normal unscheduled DNA synthesis, normal recovery of RNA synthesis, but reduced recovery of replicative DNA synthesis (51 +/- 6% the rate relative to normal controls). This reduction of recovery of replicative DNA synthesis was enhanced in the presence of a nontoxic level of caffeine to 36 +/- 5%. In this study we assess the cellular markers in two independent families that included two photosensitive patients that were identified as xeroderma pigmentosum variant. Cells from heterozygotic parents showed normal levels of unscheduled DNA synthesis, recovery of RNA synthesis, and recovery of replicative DNA synthesis, but reduced rates of recovery of replicative DNA synthesis in the presence of 1 mM caffeine (53 +/- 8% relative to the normal control). Furthermore, with a colony-forming assay, the cells showed normal survival by ultraviolet without caffeine, but slightly reduced survival by ultraviolet with 1 mM caffeine present. In one family, we confirmed inheritance of two heterozygous mis-sense mutations. One mutation is an A-->G transition at nucleotide 1840 that generates a K535E mis-sense mutation. Another mutation is an A-->C transversion at nucleotide 2003 that generates a K589 mis-sense mutation. Each of these mutations were absent in 52 unrelated Japanese individuals. These results suggest that xeroderma pigmentosum variant heterozygotes can be identified by their sensitivity to ultraviolet irradiation in the presence of nontoxic levels of caffeine.

Four radiation hypersensitivity cases and their implications for clinical radiotherapy

BACKGROUND AND PURPOSE

Over a 20 year period, four out of 2000 paediatric radiotherapy patients, treated at St. Bartholomew's Hospital (three with lymphoma, one with angiosarcoma), have revealed extreme/fatal clinical hypersensitivity in normal tissues.

PATIENTS AND METHODS

Cellular hypersensitivity was confirmed in vitro and attributed to the ataxia-telangiectasia (A-T) gene in cases I and II, a newly described defect in the DNA ligase 4 gene in case III, and a novel and as yet incompletely defined, molecular defect in case IV who presented with xeroderma pigmentosum (XP).

RESULTS

The severe clinical hypersensitivity preceded the cellular and molecular analysis, but did not manifest as a clinically exaggerated normal tissue reaction until 3+ weeks after the start of a conventionally fractionated course of radiotherapy, by which time the latent damage had been inflicted. There were no clinical stigmata to alert the clinician to a predisposing syndrome in two patients (cases I and II). We point out that approximately 20% of A-T patients are classified as variants with delayed expression of clinical symptoms, and case II falls into this category.

CONCLUSIONS

As lymphoma (incidence, one in 100000 children) constituted the majority of the diagnoses, questions arise as to: (1), the probability of other centres having experienced and being presented in the future with similar problems (particularly bearing in mind that other oncologically predisposing radiosensitivity syndromes have not been not represented in our experience); and (2), the appropriateness, efficiency and applicability of predictive assays. Unambiguous cellular radiosensitivity would have been apparent from clonal assays on fibroblast cultures from all four cases prior to treatment, but such assays take 4-6 weeks to produce results. While estimates of chromosome damage or clonal assays on pre-treatment blood derived cells would be faster, there is a health economics issue as to the general applicability of such 'screening' assays.

Xeroderma pigmentosum: the role of phototesting

We report three patients newly diagnosed as having xeroderma pigmentosum (XP). Previous photobiological studies have implicated ultraviolet (UV) B as the activating waveband in XP, causing a delayed and prolonged erythemal response. This characteristic reaction pattern has been used as a quick screening test in patients suspected of having XP, while awaiting confirmatory DNA repair studies. Two of our patients showed no abnormal erythemal responses, and one showed severe photosensitivity from 330 to 400 nm but normal UVB responses, with a peak erythema at 24 h. We conclude that the erythemal responses in XP are highly variable and cannot be considered as a reliable screening test in the diagnosis of XP.