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

Genetic predisposition to ocular surface disorders and opportunities for gene-based therapies

The ocular surface, comprised of the corneal and conjunctival epithelium, innervation system, immune components, and tear-film apparatus, plays a key role in ocular integrity as well as comfort and vision. Gene defects may result in congenital ocular or systemic disorders with prominent ocular surface involvement. Examples include epithelial corneal dystrophies, aniridia, ectrodactyly-ectodermal dysplasia-clefting (EEC) syndrome, xeroderma pigmentosum (XP), and hereditary sensory and autonomic neuropathy. In addition, genetic factors may interact with environmental risk factors in the development of several multifactorial ocular surface disorders (OSDs) such as autoimmune disorders, allergies, neoplasms, and dry eye disease. Advanced gene-based technologies have already been introduced in disease modelling and proof-of-concept gene therapies for monogenic OSDs. For instance, patient-derived induced pluripotent stem cells have been used for modelling aniridia-associated keratopathy (AAK), XP, and EEC syndrome. Moreover, CRISPR/Cas9 genome editing has been used for disease modelling and/or gene therapy for AAK and Meesmann's epithelial corneal dystrophy. A better understanding of the role of genetic factors in OSDs may be helpful in designing personalized disease models and treatment approaches. Gene-based approaches in monogenic OSDs and genetic predisposition to multifactorial OSDs such as immune-mediated disorders and neoplasms with known or possible genetic risk factors has been seldom reviewed. In this narrative review, we discuss the role of genetic factors in monogenic and multifactorial OSDs and potential opportunities for gene therapy.

Xeroderma Pigmentosum with Simultaneous Cutaneous and Ocular Squamous Cell Carcinoma

Xeroderma pigmentosum (XP) is a rare autosomal recessive disease that disrupts deoxyribonucleic acid (DNA) repair due to ultraviolet (UV) radiation. XP is characterized by extreme sensitivity to sunlight, photophobia, cutaneous lesions in the form of freckle-like hyperpigmented macules, and neoplasia on the skin surface. Malignancy is a common complication found in areas exposed to UV light. Squamous cell carcinomas (SCC) is the most common malignancy seen in patients with XP. This report illustrates a case of XP in a six-year-old girl with cutaneous and ocular SCC. The diagnosis of XP was established based on the patient’s history and the presence of typical clinical manifestations. Dermoscopy and histopathology examinations confirmed the presence of SCC on the face and eyes. The management of XP patients includes early diagnosis, lifelong UV protection, and early detection of cutaneous malignancy. Early detection and appropriate management are very important in preventing the occurrence of malignancy.

Outcomes of XEN45 gel stent using posterior small incision sub-tenon ab interno insertion (Semi-open) technique

PURPOSE

To evaluate the 12-month outcomes of a novel posterior small incision sub-tenon ab interno technique of XEN stent insertion ('Semi-open').

METHOD

Consecutive eyes underwent XEN stent insertion with the Semi-open technique by two surgeons between 1st July 2018 and 30th September 2019. All cases received subconjunctival injection of 0.1 mL of mitomycin C 0.2 mg/mL. Eyes with primary open angle glaucoma (OAG), secondary OAG or pseudophakic primary angle closure glaucoma (PACG) were included. Exclusion criteria were phakic PACG, uveitic or neovascular glaucoma and postoperative follow-up <12 months. Primary outcomes were defined by World Glaucoma Association guidelines. Secondary outcomes included change in glaucoma medications, needling rates and complications.

RESULTS

We included 37 consecutive eyes of 35 patients with primary OAG (n = 30), secondary OAG (n = 6) and pseudophakic PACG (n = 1). Thirty-one eyes (84%) received a standalone XEN implantation and 6 (16%) underwent XEN implantation combined with phacoemulsification. The IOP reduced from 19.6 ± 6.0 mmHg preoperatively to 11.2 ± 2.6 mmHg at 12 months (P < 0.01). The number of glaucoma agents reduced from 3.49 ± 1.14 preoperatively to 1.57 ± 1.36 at 12 months. At 12 months, qualified success was 97.3% and complete success was 32%, with one case requiring trabeculectomy. Needling was required in 19% of cases over the 12 month follow up. Complications included 19 cases of transient hypotony and 7 cases of transient choroidal effusion. There were no cases of exposure, bleb leak or bleb-related infection.

CONCLUSION

Semi-open XEN technique achieves high surgical success rate in the medium-term with relatively low post-operative bleb needling rate.

Ocular Surface Squamous Neoplasia Following Keratoplasty in Xeroderma Pigmentosa: A Series of Seven Cases

Purpose: To describe the clinical features and management of post-keratoplasty ocular surface squamous neoplasia (pk-OSSN) in patients with xeroderma pigmentosum (XP).Methods: Retrospective case series of seven patients with XP.Results: The mean age at diagnosis of pk-OSSN was 22 years (median, 21 years; range, 12 to 37 years). There were four males and three females. Full-thickness keratoplasty (n = 5) and Descemet stripping endothelial keratoplasty (n = 2) were performed for optical (n = 6) and therapeutic indications (n = 1). None of the patients had evidence of OSSN before or at the time of keratoplasty. The mean interval between keratoplasty and pk-OSSN was 44 months (median, 14 months; range, 3 to 109 months). The tumor epicenter was located at the limbus (n = 4), bulbar conjunctiva (n = 1) or cornea (n = 2). The mean dimension of the lesions was 12 mm (median, 11 mm; range, 6 to 18 mm). Treatment details included conjunctival/corneal tumor excision (n = 6), plaque brachytherapy (n = 3; 1 primary, 2 adjuvant) and extended enucleation (n = 1). One patient had tumor recurrence 18 months after OSSN treatment, which was treated with wide excisional biopsy. All patients are alive and free of disease over a mean follow-up period of 37 months (median, 37 months; range, 4 to 65 months).Conclusion: XP patients undergoing keratoplasty can develop OSSN several months to years after keratoplasty and require close follow-up for the same. Wide excisional biopsy with/without plaque radiotherapy is effective in the management of pk-OSSN.

Clinical and Mutational Spectrum of Xeroderma Pigmentosum in Egypt: Identification of Six Novel Mutations and Implications for Ancestral Origins

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

Hemochromatosis and Xeroderma Pigmentosum: Two (Un)Suspicious Neighbors

A 51-year-old woman, clinically diagnosed with <i>Xeroderma pigmentosum</i> (XP), showed abnormalities in liver enzymes, high ferritin and transferrin saturation levels, with ultrasonographic features of chronic liver disease, in addition to skin hyperpigmentation. Genetic testing confirmed the clinical hypothesis of hereditary hemochromatosis (HH). Due to the known proximity of HFE (6p22.2) and POLH (6p21.1) genes, accountable for HH and the XP-V variant, respectively, a genetic test was offered and a rare variant of the POLH gene was identified. We report the first confirmed case, to our knowledge, of a patient diagnosed both with XP and HH, in whom two mutated neighbor genes – POLH and HFE – were identified, possibly the result of genetic linkage.

Ocular Features in a Large Cohort of Indians With Xeroderma Pigmentosum

PURPOSE

Xeroderma pigmentosum (XP) is an extreme hypersensitivity to sunlight causing skin freckling and pigmentary changes because of defective DNA repair mechanisms. The purpose of this article is to evaluate the spectrum of ocular and systemic features in XP at a tertiary eye care center in India over 32 years.

METHODS

Data from 418 eyes of 209 patients diagnosed with XP from 1987 to 2018 were reviewed retrospectively for demographics, complaints, ocular features, systemic associations, and their management.

RESULTS

Median age at diagnosis was 2 years (interquartile range, 0.5-5 years). A total of 124 patients (59.3%) were men. There was parental consanguinity in 74.4% cases. Common ocular complaints were photophobia (47.1%), ocular discomfort (45%), defective vision (36.6%), redness (13.4%), tissue growth (12%), white spot (11.2%), and pain (10.5%). At presentation, 43.5% had corneal scars (45.5% were located inferiorly and 70.9% covered visual axis). Corneal vascularization and limbal stem cell deficiency were noted in 37.4%. A total of 56% of patients had at least 1 tumor, and 6.7% had neurological abnormalities. At least 1 ocular surgery was performed in 37.8% of patients. Ophthalmic surgical interventions included tumor excision (23%), keratoplasty (13.4%), and nontumor ocular surface surgery (3.4%).

CONCLUSIONS

XP is a disorder that has high ocular morbidity in Indian patients. The recognition of common signs and symptoms and relative frequency of various ocular complications with time trends will help in managing and reducing the sequelae of this otherwise untreatable and progressive disease.

Ocular surface biopsies of patients with xeroderma pigmentosum in the United Kingdom: a retrospective observational case series

BACKGROUND/AIMS

To describe the results of all ocular surface biopsies performed on patients with xeroderma pigmentosum (XP) under the care of the UK Nationally Commissioned XP Service as well as the treatment of any subsequent ocular surface conditions diagnosed.

METHODS

Retrospective analysis of medical records. All patients with XP seen by the service from 2010 to 2019 were included and those with ocular surface biopsies were identified. Data was collected on demographics, complementation subgroup (A-G and V), biopsy details, histopathological analysis and subsequent management.

RESULTS

Of 108 patients seen in our service, 17 underwent at least one ocular surface biopsy. 45 biopsy samples were available from 13 patients of which 65% were performed on patients from complementation subgroup C (XP-C). Biopsies were categorised as either non-mapping (clinically abnormal ocular surface tissue) or mapping (multiple sites including clinically normal tissue). 67 percent of non-mapping biopsies had a mass as their indication and 46% showed ocular surface squamous neoplasia. General non-dysplastic damage was seen in 67% of non-mapping biopsies and melanocytic changes were seen in 25% of non-mapping and 81% of mapping biopsies. 47 percent of biopsy outcomes required no additional treatment but, of those that did, 50% received mitomycin C.

CONCLUSIONS

This is the largest reported series of ocular surface biopsies in patients with XP. It identifies a background of ocular surface melanocytic, degenerative and inflammatory changes, with patients with XP-C showing the most severe effects. We highlight challenges faced in interpreting their histopathology and in planning subsequent treatments.

Xeroderma Pigmentosum: Ocular Findings in an Isolated Brazilian Group with an Identified Genetic Cluster

Purpose

Xeroderma pigmentosum (XP) is a rare autosomal recessive genetic disorder characterized by increased susceptibility to UV radiation- (UVR-) induced skin pigmentation, skin cancers, ocular surface disease, and, in some patients, sunburn and neurological degeneration. Eight different genes are affected, and the prevalence of the disease differs across the world. The present study describes the main ophthalmologic features and symptoms in patients with XP in this case series.

Methods

Patients were examined consecutively at the University Hospital of the Federal University of Goias between January 2016 and June 2018. All patients underwent ophthalmologic examination and were asked about their ophthalmological history and the presence of ocular symptoms.

Results

Twenty-one patients with genetic confirmation were evaluated. The genetic variants XPV and XPC were detected in the patients. The most prevalent findings include eyelid changes, observed in 80.9% of the patients, and ocular surface changes as punctate keratopathy, occurring in 16 patients (76.2%), corneal neovascularization, and corneal opacities. Six patients (28.5%) presented corneoconjunctival tumor. More than half of patients had previous history of treatment of ocular neoplasia. Ocular burning was the most reported symptom.

Conclusions

The ocular characteristics identified in this study corroborate the existing literature, mainly related to the surface. Concerning the XP variant and the gravity of ocular signs, XPC has earlier and more severe symptoms than XPV. Due to their relative rarity, publications of XP cases are important to understand the possible damages caused by the disease in the eyes and surrounding area.

Simultaneous squamous cell carcinoma and malignant melanoma of the conjunctiva in a teenager with xeroderma pigmentosum: Case report

Xeroderma pigmentosum (XP) is an autosomal recessive disease with ophthalmic, dermatologic, and neurologic manifestations. Ophthalmological changes are described in up to 100% of XP patients. We report a young XP patient that presented with bilateral conjunctival masses. She was treated by surgical excision with supplemental cryotherapy. The histopathological analysis revealed squamous cell carcinoma with melanosis on right eye and conjunctival melanoma on the left eye. These patients need to be followed by dermatologists and ophthalmologists to identify malignant lesions as soon as possible and also to prevent unnecessary surgery that increases mutilation.

Ocular and Periocular Tumors in Xeroderma Pigmentosum: A Study of 120 Asian Indian Patients

PURPOSE

We studied the incidence, treatment, and outcome of ocular and periocular tumors in patients with xeroderma pigmentosum (XP).

DESIGN

Retrospective case series.

METHODS

This single-institution study included 120 patients with XP who underwent intervention with excisional biopsy, enucleation, or orbital exenteration. The primary outcome measures were the occurrence of eyelid or ocular surface tumor, globe salvage, locoregional and systemic metastasis, and death.

RESULTS

The mean age at presentation was 19 years. A family history of XP was present in 32 (27%) patients. Over a mean follow-up of 61 months, 34 (28%) patients developed no ocular/adnexal tumor, 86 (72%) developed ocular surface malignancy, 15 (13%) developed eyelid malignancy, and 22 (18%) developed other head and neck malignancies. Of the 86 patients with ocular surface malignancy, 48 (56%) had unilateral tumor and 38 (44%) had bilateral tumors. Invasive squamous cell carcinoma (n = 51, 41%) was the most common ocular surface tumor. Of the 15 patients with eyelid tumors, 14 (93%) had unilateral tumor and 1 (7%) had bilateral involvement. Basal cell carcinoma (n = 8, 50%) was the most common eyelid tumor. There were events of ocular surface tumor recurrence (n = 55 eyes, 44%), eyelid tumor recurrence (n = 5 eyes, 31%), locoregional lymph node metastasis (n = 3, 2%), systemic metastasis (n = 1, 1%), and death (n = 1, 1%). Overall, globe salvage was achieved in 119 (99%) patients (both eyes were salvaged in 92 [76%] patients and at least 1 eye was salvaged in 27 [23%] patients).

CONCLUSION

XP is frequently associated with ocular surface, eyelid, and other head and neck malignancies. Lifelong follow-up is mandatory in these patients.

Macular and Retinal Nerve Fibre Layer Thinning in Xeroderma Pigmentosum: A Cross-sectional Study

The purpose of this study was to evaluate retinal thickness in different Xeroderma Pigmentosum (XP) complementation groups using spectral-domain optical coherence tomography (SD-OCT). This was a cross-sectional pilot study of 40 patients with XP. All patients had healthy-looking retinae and optic nerves on slit lamp biomicroscopy, and subtle or no neurological deficits. Patients were divided into two groups based on the known tendency for neurodegeneration associated with certain XP complementation groups. A third control group was obtained from a normative database. Using SD-OCT, we compared peripapillary retinal nerve fibre layer (pRNFL) and macular thickness between the groups. XP patients with a known tendency for neurodegeneration were found to have a statistically significant reduction in both pRNFL (p < 0.01) and macular thickness (p < 0.001) compared with healthy controls. In contrast, there was no statistically significant difference between pRNFL and macular thickness in XP patients not expected to develop neurodegeneration compared to the same control group. When both XP groups were compared, a statistically significant reduction in total pRNFL (p = 0.02) and macular thickness (p = 0.002) was found in XP patients predisposed to neurodegeneration. Our results suggest that pRNFL and macular thickness are reduced in XP patients with a known tendency for neurodegeneration, even before any marked neurological deficits become manifest. These findings demonstrate the potential role of retinal thickness as an anatomic biomarker and prognostic indicator for XP neurodegeneration.