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.

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.

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.

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.

Whole Exome Sequencing of a Patient with a Milder Phenotype of Xeroderma Pigmentosum Group C.

A 17-year-old female Korean patient (XP115KO) was previously diagnosed with Xeroderma pigmentosum group C (XPC) by Direct Sanger sequencing, which revealed a homozygous nonsense mutation in the XPC gene (rs121965088: c.1735C > T, p.Arg579Ter). While rs121965088 is associated with a poor prognosis, our patient presented with a milder phenotype. Hence, we conducted whole-exome sequencing in the patient and her family members to detect coexisting mutations that may have resulted in a milder phenotype of rs121965088 through genetic interaction. Materials and Methods: the whole-exome sequencing analysis of samples obtained from the patient and her family members (father, mother, and brother) was performed. To identify the underlying genetic cause of XPC, the extracted DNA was analyzed using Agilent's SureSelect XT Human All Exon v5. The functional effects of the resultant variants were predicted using the SNPinfo web server, and structural changes in the XPC protein using the 3D protein modeling program SWISS-MODEL. Results: Eight biallelic variants, homozygous in the patient and heterozygous in her parents, were detected. Four were found in the XPC gene: one nonsense variant (rs121965088: c.1735C > T, p.Arg579Ter) and three silent variants (rs2227998: c.2061G > A, p. Arg687Arg; rs2279017: c.2251-6A > C, intron; rs2607775: c.-27G > C, 5'UTR). The remaining four variants were found in non-XP genes, including one frameshift variant [rs72452004 of olfactory receptor family 2 subfamily T member 35 (OR2T35)], three missense variants [rs202089462 of ALF transcription elongation factor 3 (AFF3), rs138027161 of TCR gamma alternate reading frame protein (TARP), and rs3750575 of annexin A7 (ANXA7)]. Conclusions: potential candidates for genetic interactions with rs121965088 were found. The rs2279017 and rs2607775 of XPC involved mutations in the intron region, which affected RNA splicing and protein translation. The genetic variants of AFF3, TARP, and ANXA7 are all frameshift or missense mutations, inevitably disturbing the translation and function of the resultant proteins. Further research on their functions in DNA repair pathways may reveal undiscovered cellular relationships within xeroderma pigmentosum.

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.

Loss of Function Variants in the XPC Causes Severe Xeroderma Pigmentosum in Three Large Consanguineous Families.

BACKGROUND: Xeroderma pigmentosum (XP) is a rare recessively inherited disorder that presents clinical and genetic heterogeneity. Mutations in eight genes, of which seven are involved in nucleotide excision repair (NER) pathway have been reported to cause the XP. METHODS AND RESULTS: Three large consanguineous families of Pakistani origin displaying typical clinical hallmarks of XP were evaluated at clinical and molecular level. Homozygosity mapping using microsatellite markers established linkage of the families to XPC gene on chromosome 3p25.1. Sanger sequencing of the XPC gene identified a novel homozygous single bp deletion [NM_004628.5; c.1934del; p.(Pro645Leufs*5)] and two previously reported mutations that included a nonsense [c.1243 C>T; p.(Arg415*)] and a splice acceptor site (c.2251-1 G>C), all segregating with the disease phenotypes in the families. CONCLUSION: This report has extended the spectrum of mutations in the XPC gene and will also facilitate in diagnosis of XP and counselling of families inheriting it, which is the only inevitable tool for preventing the disease occurrence in future generations.

COFS type 3 in an Indian family with antenatally detected arthrogryposis.

Fetal akinesia and contractures can be caused by mutations in various genes that lead to overlapping phenotypes with contractures, rocker bottom feet, cerebellar hypoplasia, ventriculomegaly, growth retardation, pulmonary hypoplasia, cystic hygroma and cleft palate in various combinations. Cerebro-oculo-facio-skeletal (COFS) syndrome is a condition resulting from defects in DNA repair pathway, and genes involved include ERCC1 (COFS), ERCC2 (XPD), ERCC5(XPG), and ERCC6 (CSB). It is a severe disorder presenting in fetal or neonatal period with microcephaly, arthrogryposis, prominent nose, and kyphoscoliosis, and leads to early death in childhood. We report a baby with antenatally identified arthrogryposis in which the homozygous pathogenic variant in exon 8 was identified in ERCC5 gene, by targeted next generation sequencing. This was predicted to cause premature chain termination in the protein. ERCC5 gene is mainly implicated in xeroderma pigmentosum, sometimes in COFS syndrome.

Early-onset nucleotide excision repair disorders with neurological impairment: Clues for early diagnosis and prognostic counseling.

Nucleotide excision repair associated diseases comprise overlapping phenotypes and a wide range of outcomes. The early stages still remain under-investigated and underdiagnosed, even although an early recognition of the first symptoms is of utmost importance for appropriate care and genetic counseling. We systematically collected clinical and molecular data from the literature and from newly diagnosed NER patients with neurological impairment, presenting clinical symptoms before the age of 12 months, including foetal cases. One hundred and eighty-five patients were included, 13 with specific symptoms during foetal life. Arthrogryposis, microcephaly, cataracts, and skin anomalies are the most frequently reported signs in early subtypes. Non ERCC6/CSB or ERCC8/CSA genes are overrepresented compared to later onset cohorts: 19% patients of this cohort presented variants in ERCC1, ERCC2/XPD, ERCC3/XPB or ERCC5/XPG. ERCC5/XPG is even the most frequently involved gene in foetal cases (10/13 cases, [4/7 families]). In this cohort, the mutated gene, the age of onset, the type of disease, severe global developmental delay, IUGR and skin anomalies were associated with earlier death. This large survey focuses on specific symptoms that should attract the attention of clinicians towards early-onset NER diagnosis in foetal and neonatal period, without waiting for the completeness of classical criteria.

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.

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.

Influence of functional variants Asp312Asn and Lys751Gln of Xeroderma Pigmentosum Group D (XPD) and Glutathione S-transferase Mu 1 (GSTM1) and Theta 1 (GSTT1) genes on cutaneous melanoma susceptibility and prognosis.

We aimed to evaluate whether variants in repair (XPD Asp312Asn, XPD Lys751Gln) and detoxification (GSTM1, GSTT1) genes alter risk, clinicopathological aspects and survival of cutaneous melanoma (CM). Genotyping was performed in 229 CM patients and 258 controls. Individuals with XPD 312Asp/Asn or Asn/Asn plus GSTT1 null genotype were under 2.00 (95% CI: 1.06-3.79), and XPD 312Asn/Gln haplotype was under 1.44-fold (95% CI: 0.99-2.08) increased risks to CM than others. Individuals with GSTM1 plus GSTT1 null genotype had 9.61-fold (95% CI: 2.28-40.38) increased risk of metastatic CM. At 60 months of follow-up, patients with XPD 751Gln/Gln plus GSTT1 null and GSTM1 null plus GSTT1 null genotype presented 7.36 and 3.05 more chances of evolving to death in multivariate Cox analysis, respectively. In conclusion, our data indicate, for the first time, that specific variant combinations of XPD, GSTM1 and GSTT1 may increase susceptibility to CM and influence patients' clinicopathological features and survival.

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.

Xeroderma pigmentosum.

Xeroderma pigmentosum (XP) is a form of general dermatosis characterised by photo-induced cutaneous-ocular impairment and by skin cancers. In addition to these signs, there may also be neurological involvement. This disease is related to a defect in genes within the nucleotide excision repair system for the first seven genetic groups (A-G), and to an abnormality in transcription groups for the eighth group (xeroderma pigmentosum variant - XPV). Cutaneous carcinomas are the most common types of cancer seen. They may begin in childhood. Multiple melanoma commonly occurs during the course of XP but given the frequency of spontaneous regression, the incidence is underestimated. The clinical appearance is characterised by polymorphous lesions with characteristic dyschromia and in most cases it is sufficient to establish the diagnosis. Investigation of unscheduled DNA synthesis (UDS) and cell survival following ultraviolet (UV) radiation were formerly considered the reference examination for laboratory diagnosis. However, these tests are now being replaced by new molecular biology techniques to screen for the genetic mutations characteristic of the disease. These techniques have proved extremely useful in identifying heterozygous patients and in antenatal diagnosis. Photoprotection is the key preventive measure: patients must avoid all exposure to the sun and to artificial sources of UV radiation. The therapeutic arsenal has recently been enriched by several modern therapeutic methods used to destroy cutaneous tumours such as imiquimod and photodynamic therapy (PDT). These approaches are valuable since they eliminate incipient tumours while sparing healthy skin. Surgery and cryosurgery are the most suitable methods for treating cutaneous tumours in children. Chemotherapy may be considered an alternative for the treatment of keratoacanthomas and squamous cell carcinomas (SCC). Cryosurgery may be combined with other therapeutic approaches to eliminate SCC of the lip. Management of these patients in reference centres, coupled with assistance from associations providing support for patients' families, has resulted in improved quality of therapy while slowing down disease progression.

Ophthalmic Manifestations of Xeroderma Pigmentosum: A Perspective from the United Kingdom.

PURPOSE: To document the ocular manifestations of xeroderma pigmentosum (XP), presenting via the United Kingdom (UK) XP service, and to analyze the correlations between XP genotype and ophthalmic phenotype. DESIGN: Prospective observational case series. SUBJECTS: Eighty-nine patients seen by the UK Nationally Commissioned XP Service, from April 2010 to December 2014, with a genetically confirmed diagnosis of XP. METHODS: Patients underwent a full ophthalmic examination at each visit. Clinical features from both eyes were recorded on a standard proforma. The most recent assessments were analyzed. A 2-tailed Fisher exact test was used to assess for differences in ocular features between patients in XP subgroups with impaired transcription coupled nucleotide excision repair (TC-NER) (category 1: XP-A, B, D, F, and G) and preserved TC-NER (category 2: XP-C, E, and V). MAIN OUTCOME MEASURES: Lid and periocular abnormalities, ocular surface pathologies, neuro-ophthalmologic abnormalities, lens and retinal abnormalities, and visual acuity (VA). RESULTS: Ninety-three percent of XP patients in our cohort had ocular involvement, with 65% describing photophobia. The most common abnormalities were in the periocular skin and ocular surface, including interpalpebral conjunctival melanosis (44%) and conjunctival injection (43%). Eleven percent of patients had required treatment for periocular cancers and 2% for ocular surface cancers. The most common neuro-ophthalmologic finding was minimal pupillary reaction to light (25%). Patients in category 2 had significantly more ocular surface abnormalities than patients in category 1, including a greater proportion of conjunctival injection (P = 0.003), conjunctival corkscrew vessels (P < 0.001), corneal scarring (P = 0.01) and pingueculae under the age of 50 (P = 0.02). Meanwhile, patients in category 1 had a higher proportion of poorly reactive pupils (P < 0.001) and abnormal ocular movements (P = 0.03) compared with those in category 2. Five patients (6%) presented to ophthalmologists with ocular surface signs related to XP, before any formal diagnosis of XP was made. CONCLUSIONS: A large proportion of XP patients have ocular involvement. Regular examination by an ophthalmologist is essential, especially in screening for eyelid and ocular surface tumors. The ocular phenotype-genotype segregation within XP patients suggests that XP is a heterogeneous and complex disease. With further study, we hope to offer these patients more individualized patient care.

Expansion of the genotypic and phenotypic spectrum of xeroderma pigmentosum in Chinese population.

BACKGROUND: Xeroderma pigmentosum (XP) is a rare genodermatosis characterized by exaggerated sunburn reactions, freckle-like pigmentation, and a high possibility of developing cutaneous tumors. XP comprised seven complementation groups (from XP-A to XP-G) and a variant form XP-V. METHODS: This study was based on five unrelated Chinese families with six patients clinically suspected to be XP. Mutation screening was performed by direct sequencing of the entire coding region of eight XP genes. RESULTS: All of the pathogenic mutations were identified by mutational analysis, including four novel mutations. CONCLUSIONS: Our study successfully identified the pathogenic mutations in six XP patients (three XP-A, one XP-G, one XP-V, and a rare XP-D group in Chinese population). We reviewed the reported XP cases with mutations in the Chinese population and concluded that four complementation groups (XP-A, XP-C, XP-G, and XP-V) that occupy the major proportion should be considered as a first step in genetic detection (especially, XPA is the most common group, and unlike in other populations, XP-G is not rare in the Chinese population). Moreover, XP-D and XP-F, two rare subgroups, should also be added for further mutational analysis. Further, we provide some information for Chinese dermatologists that, when an early diagnosis is made, XP-C and XP-V patients can have relatively good prognoses.

A 10-year follow-up of a child with mild case of xeroderma pigmentosum complementation group D diagnosed by whole-genome sequencing.

BACKGROUND: Most patients with xeroderma pigmentosum complementation group D (XP-D) from Western countries suffer from neurological symptoms, whereas Japanese patients display only skin manifestations without neurological symptoms. We have previously suggested that these differences in clinical manifestations in XP-D patients are attributed partly to a predominant mutation in ERCC2, and the allele frequency of S541R is highest in Japan. METHODS: We diagnosed a child with mild case of XP-D by the evaluation of DNA repair activity and whole-genome sequencing, and followed her ten years. RESULTS: Skin cancer, mental retardation, and neurological symptoms were not observed. Her minimal erythema dose was 41 mJ/cm(2) , which was slightly lower than that of healthy Japanese volunteers. The patient's cells showed sixfold hypersensitivity to UV in comparison with normal cells. Post-UV unscheduled DNA synthesis was 20.4%, and post-UV recovery of RNA synthesis was 58% of non-irradiated samples, which was lower than that of normal fibroblasts. Genome sequence analysis indicated that the patient harbored a compound heterozygous mutation of c.1621A>C and c.591_594del, resulting in p.S541R and p.Y197* in ERCC2: then, patient was diagnosed with XP-D. Y197* has not been described before. CONCLUSION: Her mild skin manifestations might be attributed to the mutational site on her genome and daily strict sun protection. c.1621A>C might be a founder mutation of ERCC2 among Japanese XP-D patients, as it was identified most frequently in Japanese XP-D patients and it has not been found elsewhere outside Japan.

Descemet Stripping Automated Endothelial Keratoplasty for Endothelial Dysfunction in Xeroderma Pigmentosum: A Clinicopathological Correlation and Review of Literature.

Xeroderma pigmentosum (XP) mainly affects the ocular surface; however, endothelial damage may also occur. We would like to report changes in the endothelial-Descemet layer and review the literature on similar findings in patients with XP, including the role of Descemet stripping automated endothelial keratoplasty (DSAEK) in the management of a 21-year-old man who presented with nonresolving corneal edema in the right eye after excision biopsy for conjunctival intraepithelial neoplasia. His best-corrected visual acuity (BCVA) was 20/200 in the right eye and 20/20 in the left eye. On general examination, there was patchy hyperpigmentation of the exposed areas of skin suggestive of XP. On examination of the right eye, there was stromal edema involving the exposed half of cornea. The left eye appeared normal. Pachymetry readings were 860 and 600 µm in the right and left eye, respectively. Descemet stripping automated endothelial keratoplasty was performed for endothelial dysfunction and the stripped endothelium, and Descemet membrane (DM) was sent for histopathologic evaluation. Postoperatively, the donor lenticule was well apposed and the overlying stromal edema resolved. The patient achieved a BCVA of 20/30 in the right eye without progression of corneal scarring at 1-year follow-up. In the meanwhile, however, the left eye developed corneal edema. Histopathology revealed gross attenuation of endothelial cells with uniform thickness of the DM. Corneal endothelial dysfunction in XP is amenable to treatment with DSAEK.

Atypical Clinical Presentation of Xeroderma Pigmentosum in a Patient Harboring a Novel Missense Mutation in the XPC Gene: The Importance of Clinical Suspicion.

BACKGROUND: Xeroderma pigmentosum (XP) is a genodermatosis caused by abnormal DNA repair. XP complementation group C (XPC) is the most frequent type in Mediterranean countries. We describe a case with a novel mutation in the XPC gene. CASE: A healthy Caucasian male patient was diagnosed with multiple primary melanomas. Digital follow-up and molecular studies were carried out. RESULTS: During digital follow-up 8 more additional melanomas were diagnosed. Molecular studies did not identify mutations in CDKN2A, CDK4 or MITF genes. Two heterozygous mutations in the XPC gene were detected: c.2287delC (p.Leu763Cysfs*4) frameshift and c.2212A>G (p.Thr738Ala) missense mutations. CONCLUSION: The p.Thr738Ala missense mutation has not been previously described. Missense mutations in the XPC gene may allow partial functionality that could explain this unusual late onset XP. Atypical clinical presentation of XPC could be misdiagnosed when genetic aberrations allow partial DNA repair capacity.