Pseudoxanthoma elasticum - Genetics, pathophysiology, and clinical presentation.

Pseudoxanthoma elasticum (PXE) is an autosomal-recessively inherited multisystem disease. Mutations in the ABCC6-gene are causative, coding for a transmembrane transporter mainly expressed in hepatocytes, which promotes the efflux of adenosine triphosphate (ATP). This results in low levels of plasma inorganic pyrophosphate (PPi), a critical anti-mineralization factor. The clinical phenotype of PXE is characterized by the effects of elastic fiber calcification in the skin, the cardiovascular system, and the eyes. In the eyes, calcification of Bruch's membrane results in clinically visible lesions, including peau d'orange, angioid streaks, and comet tail lesions. Frequently, patients must be treated for secondary macular neovascularization. No effective therapy is available for treating the cause of PXE, but several promising approaches are emerging. Finding appropriate outcome measures remains a significant challenge for clinical trials in this slowly progressive disease. This review article provides an in-depth summary of the current understanding of PXE and its multi-systemic manifestations. The article offers a detailed overview of the ocular manifestations, including their morphological and functional consequences, as well as potential complications. Lastly, previous and future clinical trials of causative treatments for PXE are discussed.

Perspectives and Update on the Global Shortage of Verteporfin (Visudyne®).

An ongoing global shortage of verteporfin (Visudyne®) limits the treatment possibilities for several chorioretinal diseases, including central serous chorioretinopathy, choroidal hemangioma, and polypoidal choroidal vasculopathy. Verteporfin is required to perform photodynamic therapy in these ocular diseases. Therefore, the current situation has a substantial impact on eye care worldwide. The worldwide supply of verteporfin appears to be manufactured by a single factory, which is situated in the United States. The distribution of verteporfin is done by different companies for different regions of the world. Official communication on the shortage by the responsible companies has been scarce and over the past years several promises with regards to resolution of the shortage have not been fulfilled. The delivery of new batches of verteporfin is at irregular intervals, unpredictable, and may not be fairly balanced between different regions or countries in the world. To ensure a fair distribution of available verteporfin within a country, several measures can be taken. In the Netherlands, a national committee, consisting of ophthalmologists, is in place to arrange this. On the European level, the European Union and European Medicine Agency have plans to monitor medicine shortages more closely and to intervene if necessary. With a more intensified monitoring and regulation of medicine supplies, future impending shortages may be prevented. Remarkably, the amount of medicine shortages is increasing, having a significant and sometimes irreversible impact on patient care. Thus, efforts should be undertaken to minimize the consequences and, whenever possible, to prevent future medicine shortages.

Bruch's Membrane Calcification in Pseudoxanthoma Elasticum: Comparing Histopathology and Clinical Imaging.

Purpose: To investigate the histology of Bruch's membrane (BM) calcification in pseudoxanthoma elasticum (PXE) and correlate this to clinical retinal imaging. Design: Experimental study with clinicopathological correlation. Subjects and Controls: Six postmortem eyes from 4 PXE patients and 1 comparison eye from an anonymous donor without PXE. One of the eyes had a multimodal clinical image set for comparison. Methods: Calcification was labeled with OsteSense 680RD, a fluorescent dye specific for hydroxyapatite, and visualized with confocal microscopy. Scanning electron microscopy coupled with energy-dispersive x-ray spectroscopy (SEM-EDX) and time-of-flight secondary ion mass spectrometry (TOF-SIMs) were used to analyze the elemental and ionic composition of different anatomical locations. Findings on cadaver tissues were compared with clinical imaging of 1 PXE patient. Main Outcome Measures: The characteristics and topographical distribution of hydroxyapatite in BM in eyes with PXE were compared with the clinical manifestations of the disease. Results: Analyses of whole-mount and sectioned PXE eyes revealed an extensive, confluent OsteoSense labeling in the central and midperipheral BM, transitioning to a speckled labeling in the midperiphery. These areas corresponded to hyperreflective and isoreflective zones on clinical imaging. Scanning electron microscopy coupled with energy-dispersive x-ray spectroscopy and TOF-SIMs analyses identified these calcifications as hydroxyapatite in BM of PXE eyes. The confluent fluorescent appearance originates from heavily calcified fibrous structures of both the collagen and the elastic layers of BM. Calcification was also detected in an aged comparison eye, but this was markedly different from PXE eyes and presented as small snowflake-like deposits in the posterior pole. Conclusions: Pseudoxanthoma elasticum eyes show extensive hydroxyapatite deposition in the inner and outer collagenous and elastic BM layers in the macula with a gradual change toward the midperiphery, which seems to correlate with the clinical phenotype. The snowflake-like calcification in BM of an aged comparison eye differed markedly from the extensive calcification in PXE. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

A cis-regulatory element regulates ERAP2 expression through autoimmune disease risk SNPs.

Single-nucleotide polymorphisms (SNPs) near the ERAP2 gene are associated with various autoimmune conditions, as well as protection against lethal infections. Due to high linkage disequilibrium, numerous trait-associated SNPs are correlated with ERAP2 expression; however, their functional mechanisms remain unidentified. We show by reciprocal allelic replacement that ERAP2 expression is directly controlled by the splice region variant rs2248374. However, disease-associated variants in the downstream LNPEP gene promoter are independently associated with ERAP2 expression. Allele-specific conformation capture assays revealed long-range chromatin contacts between the gene promoters of LNPEP and ERAP2 and showed that interactions were stronger in patients carrying the alleles that increase susceptibility to autoimmune diseases. Replacing the SNPs in the LNPEP promoter by reference sequences lowered ERAP2 expression. These findings show that multiple SNPs act in concert to regulate ERAP2 expression and that disease-associated variants can convert a gene promoter region into a potent enhancer of a distal gene.

Association of Risk Variants in the CFH Gene With Elevated Levels of Coagulation and Complement Factors in Idiopathic Multifocal Choroiditis.

Importance: Idiopathic multifocal choroiditis (MFC) is poorly understood, thereby hindering optimal treatment and monitoring of patients. Objective: To identify the genes and pathways associated with idiopathic MFC. Design, Setting, and Participants: This was a case-control genome-wide association study (GWAS) and protein study of blood plasma samples conducted from March 2006 to February 2022. This was a multicenter study involving 6 Dutch universities. Participants were grouped into 2 cohorts: cohort 1 consisted of Dutch patients with idiopathic MFC and controls, and cohort 2 consisted of patients with MFC and controls. Plasma samples from patients with idiopathic MFC who had not received treatment were subjected to targeted proteomics. Idiopathic MFC was diagnosed according to the Standardization of Uveitis Nomenclature (SUN) Working Group guidelines for punctate inner choroidopathy and multifocal choroiditis with panuveitis. Data were analyzed from July 2021 to October 2022. Main outcomes and measures: Genetic variants associated with idiopathic MFC and risk variants associated with plasma protein concentrations in patients. Results: This study included a total of 4437 participants in cohort 1 (170 [3.8%] Dutch patients with idiopathic MFC and 4267 [96.2%] controls; mean [SD] age, 55 [18] years; 2443 female [55%]) and 1344 participants in cohort 2 (52 [3.9%] patients with MFC and 1292 [96.1%] controls; 737 male [55%]). The primary GWAS association mapped to the CFH gene with genome-wide significance (lead variant the A allele of rs7535263; odds ratio [OR], 0.52; 95% CI, 0.41-0.64; P = 9.3 × 10-9). There was no genome-wide significant association with classical human leukocyte antigen (HLA) alleles (lead classical allele, HLA-A*31:01; P = .002). The association with rs7535263 showed consistent direction of effect in an independent cohort of 52 cases and 1292 control samples (combined meta-analysis OR, 0.58; 95% CI, 0.38-0.77; P = 3.0 × 10-8). In proteomic analysis of 87 patients, the risk allele G of rs7535263 in the CFH gene was strongly associated with increased plasma concentrations of factor H-related (FHR) proteins (eg, FHR-2, likelihood ratio test, adjusted P = 1.1 × 10-3) and proteins involved in platelet activation and the complement cascade. Conclusions and relevance: Results suggest that CFH gene variants increase systemic concentrations of key factors of the complement and coagulation cascades, thereby conferring susceptibility to idiopathic MFC. These findings suggest that the complement and coagulation pathways may be key targets for the treatment of idiopathic MFC.

Exploring Imaging Characteristics Associated With Disease Activity in Idiopathic Multifocal Choroiditis: A Multimodal Imaging Approach.

PURPOSE: To identify characteristics on multimodal imaging (MMI) in idiopathic multifocal choroiditis (MFC) that can identify inflammatory activity and distinguish choroidal neovascularization (CNV) activity from inflammatory activity. DESIGN: Prospective cohort study. METHODS: MMI consisted of spectral-domain optical coherence tomography (angiography) (SD-OCT(A)), fundus autofluorescence, fundus photography, infrared imaging, fluorescein angiography (FA), and indocyanine green angiography (ICGA). MMI characteristics obtained during active and inactive disease were compared within the same lesion. Secondly, MMI characteristics were compared between active inflammatory lesions with and without CNV activity. RESULTS: Fifty patients (110 lesions) were included. In 96 lesions without CNV activity, the mean focal choroidal thickness was increased during the active disease (205 µm) compared to the inactive disease (180 µm) (P ≤ .001). Lesions with inflammatory activity typically demonstrated moderately reflective material located in the sub-retinal pigment epithelium (RPE) and/or in the outer retina with disruption of the ellipsoid zone. During the inactive stage of the disease, the material disappeared or became hyperreflective and indistinguishable from the RPE. During the active stage of the disease, the area of hypoperfusion in the choriocapillaris significantly increased as visualized on both ICGA and SD-OCTA. CNV activity in 14 lesions was associated with subretinal material with a mixed reflectivity and hypotransmission of light to the choroid on SD-OCT and leakage on FA. SD-OCTA identified vascular structures in all active CNV lesions and in 24% of lesions without CNV activity (showing old, quiescent CNV membranes). CONCLUSION: Inflammatory activity in idiopathic MFC was associated with several MMI characteristics, including focally increased choroidal thickness. These characteristics can guide clinicians in the challenging process of the evaluation of disease activity in idiopathic MFC patients.

Idiopathic Multifocal Choroiditis and Punctate Inner Choroidopathy - Evaluation of Risk Factors for Increased Relapse Rate: A 2-Year Prospective Observational Cohort Study.

INTRODUCTION: The aim of this study was to describe the course of disease in patients with idiopathic multifocal choroiditis (MFC) and punctate inner choroidopathy (PIC) and to identify risk factors associated with an increased relapse rate of disease activity. METHODS: In this prospective observational cohort study, demographical and clinical data were collected concerning the relapses rate of disease activity, the conclusions of the multimodal imaging results, treatment, complications, and self-reported quality of life. Disease activity was defined as new inflammatory lesions or active inflammation in preexisting chorioretinal lesions either with or without active choroidal neovascularization (CNV). Linear regression analysis was performed to identify risk factors associated with an increased relapse rate. RESULTS: In total, 122 eyes of 82 patients (93% females) were included with a median age (IQR) of 45 (37-54) years. A history of secondary CNV was present in 66% of the eyes. During follow-up, the best-corrected visual acuity remained stable despite a median relapse rate (IQR) of 1.0 (0.25-3). Cycles of oral corticosteroids were given in 59% of the patients, 72% were treated at baseline or started treatment during follow-up with a disease-modifying antirheumatic drug (DMARD), and 35% with a biological agent in addition to the DMARD. Both a history of secondary CNV (B = 1.2, 95% CI: 0.7-1.7, p = 3.6 × 10-5) and high myopia (<-6 diopters) (B = 0.6, 95% CI: 0.1-1.1, p = 0.02) independently increased the relapse rate of disease activity. DISCUSSION/CONCLUSION: A history of secondary CNV and high myopia were associated with an increased relapse rate of disease activity. Moreover, the results of this study emphasize the challenging character of treating patients with MFC/PIC.

The Natural History of Leber Congenital Amaurosis and Cone-Rod Dystrophy Associated with Variants in the GUCY2D Gene.

OBJECTIVE: To describe the spectrum of Leber congenital amaurosis (LCA) and cone-rod dystrophy (CORD) associated with the GUCY2D gene and to identify potential end points and optimal patient selection for future therapeutic trials. DESIGN: International, multicenter, retrospective cohort study. SUBJECTS: Eighty-two patients with GUCY2D-associated LCA or CORD from 54 families. METHODS: Medical records were reviewed for medical history, best-corrected visual acuity (BCVA), ophthalmoscopy, visual fields, full-field electroretinography, and retinal imaging (fundus photography, spectral-domain OCT [SD-OCT], fundus autofluorescence). MAIN OUTCOMES MEASURES: Age of onset, evolution of BCVA, genotype-phenotype correlations, anatomic characteristics on funduscopy, and multimodal imaging. RESULTS: Fourteen patients with autosomal recessive LCA and 68 with autosomal dominant CORD were included. The median follow-up times were 5.2 years (interquartile range [IQR] 2.6-8.8 years) for LCA and 7.2 years (IQR 2.2-14.2 years) for CORD. Generally, LCA presented in the first year of life. The BCVA in patients with LCA ranged from no light perception to 1.00 logarithm of the minimum angle of resolution (logMAR) and remained relatively stable during follow-up. Imaging for LCA was limited but showed little to no structural degeneration. In patients with CORD, progressive vision loss started around the second decade of life. The BCVA declined annually by 0.022 logMAR (P < 0.001) with no difference between patients with the c.2513G>A and the c.2512C>T GUCY2D variants (P = 0.798). At the age of 40 years, the probability of being blind or severely visually impaired was 32%. The integrity of the ellipsoid zone (EZ) and that of the external limiting membrane (ELM) on SD-OCT correlated significantly with BCVA (Spearman ρ = 0.744, P = 0.001, and ρ = 0.712, P < 0.001, respectively) in those with CORD. CONCLUSIONS: Leber congenital amaurosis associated with GUCY2D caused severe congenital visual impairment with relatively intact macular anatomy on funduscopy and available imaging, suggesting long preservation of photoreceptors. Despite large variability, GUCY2D-associated CORD generally presented during adolescence, with a progressive loss of vision, and culminated in severe visual impairment during mid-to-late adulthood. The integrity of the ELM and EZ may be suitable structural end points for therapeutic studies of GUCY2D-associated CORD.

IS VAGINAL DELIVERY HARMFUL TO PATIENTS WITH PSEUDOXANTHOMA ELASTICUM?

BACKGROUND/PURPOSE: To investigate the effect of a vaginal delivery (VD) on retinal pathology in patients with pseudoxanthoma elasticum. METHODS: Retrospective case series. All 14 consecutive women with pseudoxanthoma elasticum who visited the ophthalmology department during pregnancy and after delivery between 2010 and 2018 were included. Prepartum and postpartum imaging consisted of color imaging, near-infrared imaging, and optical coherence tomography and was assessed on occurrence of (sub)retinal hemorrhages and change in angioid streaks. RESULTS: Fourteen patients (15 deliveries) were included, of whom 11 patients (79%) had a VD and three patients (21%) a secondary caesarian section. Data of three patients with VD (four deliveries) could not be assessed for (sub)retinal hemorrhage within 10 weeks postpartum. The median age at delivery was 31 years (IQR 29-37). One patient with VD (9%) had a choroidal neovascularization and was treated with anti-VEGF injections before assisted delivery. All patients had angioid streaks in the central 5,500 µ m of the posterior pole of both eyes. After delivery, no patient in the VD or caesarian section group presented with progression of angioid streaks or (sub)retinal hemorrhage. CONCLUSION: Pushing during the expulsion phase of VD seems safe in pseudoxanthoma elasticum patients without active choroidal neovascularization, and the presence of angioid streaks alone should not be an indication for elective caesarian section.

Idiopathic multifocal choroiditis and punctate inner choroidopathy: an evaluation in pregnancy.

PURPOSE: To evaluate the clinical course of idiopathic multifocal choroiditis (MFC) and punctate inner choroidopathy (PIC) and the efficacy and safety of treatment options during pregnancy. METHODS: Patients with MFC or PIC and a pregnancy in 2011-2019 from two academic centres were enrolled. For the most recent pregnancy, data on best-corrected visual acuity (BCVA) before and after pregnancy, relapse rate in pregnancy and postpartum period and obstetric, maternal and neonatal outcomes were collected. Treatment regimens consisted of a wait-and-see regime and an immunosuppressive treatment regime with systemic corticosteroids and/or azathioprine, both combined with intravitreal antivascular endothelial growth factor injections when indicated. RESULTS: Sixteen women (26 affected eyes) were included. Median Snellen BCVA was 20/19 before pregnancy and 20/18 after delivery. In seven pregnancies a wait-and-see regime and in nine pregnancies an immunosuppressive treatment regime was carried out. Fourteen intravitreal anti-VEGF injections were given in six pregnancies. The relapse rate during pregnancy was 44% and in the postpartum period 31%. Maternal/obstetrical and fetal complications occurred in 31% and 13% of the pregnancies, respectively. Fifteen healthy children were born and one pregnancy ended in a stillbirth in a patient with a complicated obstetrical history. One patient treated with azathioprine developed intrahepatic cholestasis of pregnancy (ICP). CONCLUSIONS: Among women with MFC and PIC BCVA remained stable during pregnancy despite a relapse rate of 44% in pregnancy. No major maternal, obstetric and fetal complications occurred in pregnant patients treated with systemic corticosteroids, azathioprine or intravitreal anti-VEGF injections, though one patient developed ICP while treated with azathioprine.

X-Linked Retinoschisis: Novel Clinical Observations and Genetic Spectrum in 340 Patients.

PURPOSE: To describe the natural course, phenotype, and genotype of patients with X-linked retinoschisis (XLRS). DESIGN: Retrospective cohort study. PARTICIPANTS: Three hundred forty patients with XLRS from 178 presumably unrelated families. METHODS: This multicenter, retrospective cohort study reviewed medical records of patients with XLRS for medical history, symptoms, visual acuity (VA), ophthalmoscopy, full-field electroretinography, and retinal imaging (fundus photography, spectral-domain [SD] OCT, fundus autofluorescence). MAIN OUTCOME MEASURES: Age at onset, age at diagnosis, severity of visual impairment, annual visual decline, and electroretinography and imaging findings. RESULTS: Three hundred forty patients were included with a mean follow-up time of 13.2 years (range, 0.1-50.1 years). The median ages to reach mild visual impairment and low vision were 12 and 25 years, respectively. Severe visual impairment and blindness were observed predominantly in patients older than 40 years, with a predicted prevalence of 35% and 25%, respectively, at 60 years of age. The VA increased slightly during the first 2 decades of life and subsequently transitioned into an average annual decline of 0.44% (P < 0.001). No significant difference was found in decline of VA between variants that were predicted to be severe and mild (P = 0.239). The integrity of the ellipsoid zone (EZ) as well as the photoreceptor outer segment (PROS) length in the fovea on SD OCT correlated significantly with VA (Spearman's ρ = -0.759 [P < 0.001] and -0.592 [P = 0.012], respectively). Fifty-three different RS1 variants were found. The most common variants were the founder variant c.214G→A (p.(Glu72Lys)) (101 patients [38.7%]) and a deletion of exon 3 (38 patients [14.6%]). CONCLUSIONS: Large variabilities in phenotype and natural course of XLRS were seen in this study. In most patients, XLRS showed a slow deterioration starting in the second decade of life, suggesting an optimal window of opportunity for treatment within the first 3 decades of life. The integrity of EZ as well as the PROS length on SD OCT may be important in choosing optimal candidates for treatment and as potential structural end points in future therapeutic studies. No clear genotype-phenotype correlation was found.

Genotype-phenotype correlation in pseudoxanthoma elasticum.

BACKGROUND AND AIMS: Pseudoxanthoma elasticum (PXE) is caused by variants in the ABCC6 gene. It results in calcification in the skin, peripheral arteries and the eyes, but has considerable phenotypic variability. We investigated the association between the ABCC6 genotype and calcification and clinical phenotypes in these different organs. METHODS: ABCC6 sequencing was performed in 289 PXE patients. Genotypes were grouped as two truncating, mixed, or two non-truncating variants. Arterial calcification mass was quantified on whole body, low dose CT scans; and peripheral arterial disease was measured with the ankle brachial index after treadmill test. The presence of pseudoxanthoma in the skin was systematically scored. Ophthalmological phenotypes were the length of angioid streaks as a measure of Bruchs membrane calcification, the presence of choroidal neovascularizations, severity of macular atrophy and visual acuity. Regression models were built to test the age and sex adjusted genotype-phenotype association. RESULTS: 158 patients (median age 51 years) had two truncating variants, 96 (median age 54 years) a mixed genotype, 18 (median age 47 years) had two non-truncating variants. The mixed genotype was associated with lower peripheral (ß: 0.39, 95%CI:-0.62;-0.17) and total (ß: 0.28, 95%CI:-0.47;-0.10) arterial calcification mass scores, and lower prevalence of choroidal neovascularizations (OR: 0.41 95%CI:0.20; 0.83) compared to two truncating variants. No association with pseudoxanthomas was found. CONCLUSIONS: PXE patients with a mixed genotype have less severe arterial and ophthalmological phenotypes than patients with two truncating variants in the ABCC6 gene. Research into environmental and genetic modifiers might provide further insights into the unexplained phenotypic variability.

The efficacy of adalimumab in treating patients with central multifocal choroiditis.

PURPOSE: To evaluate the efficacy of adalimumab in patients with central multifocal choroiditis (cMFC) refractory to conventional corticosteroid-sparing immunomodulatory agents (IMT). METHODS: Medical records were reviewed from all patients with cMFC and treated with adalimumab with follow-up of at least 12 months. The study focused on the 12 months prior to and after the start of adalimumab. The imaging results were independently evaluated by two ophthalmologists. The main outcomes were the number of patients without a relapse of disease activity in 12 months after the start of adalimumab and the ability to stop the systemic corticosteroids to evaluate the corticosteroid-sparing effect. RESULTS: Twelve patients (18 eyes) were included. In 8/12 (67%) patients no relapse of disease activity was observed in the 12 months after the start of adalimumab. In 9/12 patients the systemic corticosteroid treatment could be stopped and in an additional 2 patients tapered to ≤7,5mg daily. In the 12 months before the start of adalimumab, the patients experienced a median of 3 (range 2-4) relapses of disease activity. Nine patients experienced relapses while treated with a combination of systemic corticosteroids (mean dose 13,6 mg; range 5-25 mg) and IMT. Moreover, 3 patients treated with IMT, experienced relapses after tapering and stopping the systemic corticosteroids. In all eyes (n = 5) with CNV before the start of adalimumab, the intravitreal anti-VEGF injections could be stopped after the start of adalimumab. CONCLUSIONS: AND IMPORTANCE: Adalimumab may be effective in patients with cMFC refractory to IMT and may be considered as a treatment option in patients with cMFC.

The effect of etidronate on choroidal neovascular activity in patients with pseudoxanthoma elasticum.

AIM: To assess the effect of the bisphosphonate etidronate on choroidal neovascular (CNV) activity in patients with pseudoxanthoma elasticum (PXE). METHODS: This is an ancillary study in a single center, randomized, double-blind placebo-controlled trial (RCT) in which 74 patients with PXE were assigned to either one-year etidronate or placebo treatment. Spectral domain optical coherence tomography (SD-OCT) imaging and color fundus photography were performed every three months for one year and were systematically assessed on signs of CNV activity. RESULTS: In the etidronate group, 11 (30%) of the patients had CNV activity at baseline, compared to 25 (67%) of the patients in the placebo group (P = 0.005). The proportion of eyes with CNV activity during the study ranged from 18-33% in the etidronate group and 42-56% in the placebo group and no significant difference in improvement or worsening of CNV activity was found (P = 0.168). Using a generalized mixed model for repeated measures, there was a protective effect of etidronate in crude analysis (RR 0.86, 95% CI 0.75-0.98) that disappeared when adjusting for baseline CNV activity (RR 0.97, 95% CI 0.84-1.13). CONCLUSION: In this post-hoc RCT analysis we did not observe a protecting or deteriorating effect of etidronate on CNV activity in patients with PXE after adjustment for baseline CNV.

A Reflectivity Measure to Quantify Bruch's Membrane Calcification in Patients with Pseudoxanthoma Elasticum Using Optical Coherence Tomography.

Purpose: Progressive calcification of Bruch's membrane (BM) causes considerable visual morbidity in patients with pseudoxanthoma elasticum (PXE). Since calcification is hyperreflective on optical coherence tomography (OCT), our aim was to measure BM calcification with OCT imaging. Methods: Case-control study with 45 patients with PXE under 40 years (range, 11-39) and 25 controls (range, 14-39). Spectralis HRA-OCT imaging consisted of seven macular B-scans with 250-µm spacing. Retinal segmentation was performed with the IOWA Reference Algorithms. MATLAB was used to extract and average z-axis reflectivity profiles. Layer reflectivities were normalized to the ganglion cell and inner plexiform layers. Both median and peak layer reflectivities were compared between patients with PXE and controls. The discriminative value of the retinal pigment epithelium (RPE)-BM peak reflectivity was analyzed using receiver operating characteristic analysis. Results: The reflectivity profile of patients with PXE differed from controls in the outer retinal layers. The normalized median RPE-BM reflectivity was 41.1 (interquartile range [IQR], 26.3-51.9) in patients with PXE, compared with 22.5 (IQR, 19.3-29.5) in controls (P = 2.09 × 10-3). The normalized RPE-BM peak reflectivity was higher in patients with PXE (67.5; IQR, 42.1-84.2) than in controls (32.7; IQR, 25.7-38.9; P = 2.43 × 10-5) and had a high discriminative value with an area under the curve of 0.85 (95% confidence interval, 0.76-0.95). In patients with PXE under 40 years, increasing age did not have a statistically significant effect on the RPE-BM peak reflectivity (patients under 20 years: 44.2 [IQR, 40.5-74.6]; 20-30 years: 66.0 [IQR, 45.1-83.8]; 30-40 years: 70.8 [IQR, 49.0-88.0], P = 0.47). Conclusions: BM calcification can be measured as increased RPE-BM reflectivity in young patients with PXE and has a high discriminative value. Translational Relevance: In patients with PXE, the OCT reflectivity of Bruch's membrane may be the first biomarker for Bruch's membrane calcification and a valuable ophthalmologic endpoint in clinical trials.

The Extent of Angioid Streaks Correlates With Macular Degeneration in Pseudoxanthoma Elasticum.

PURPOSE: To investigate whether the extent of Bruch's membrane calcification is associated with choroidal neovascularization (CNV) and macular atrophy in patients with pseudoxanthoma elasticum (PXE) by using the extent of angioid streaks as a surrogate marker for the degree of Bruch's membrane calcification. DESIGN: Retrospective cross-sectional study. METHODS: We investigated 301 patients with PXE (median age, 52 years; range, 9-79 years) in a tertiary referral center. For both eyes, we graded the extent of angioid streaks, that is, their distance from the optic disc, into 5 groups. Imaging was systematically assessed for signs of CNV and macular atrophy. Associations between the extent of angioid streaks and CNV or macular atrophy were investigated using regression analysis. RESULTS: CNV was present in 148 patients (49%) and retinal atrophy in 71 patients (24%). The extent of angioid streaks was associated with older age (P for trend = 1.92 × 10-15) and a higher prevalence of CNV and/or macular atrophy (P for trend = 4.22 × 10-10 and P for trend = 5.17 × 10-6, respectively). In addition, the extent of angioid streaks was associated with the presence of CNV when adjusted for age and sex (odds ratio, 1.9; 95% confidence interval, 1.3-2.9) and with more severe macular atrophy (proportional odds ratio, 2.3; 95% confidence interval, 1.5-3.6). CONCLUSIONS: In patients with PXE, longer angioid streaks are associated with an increased risk of CNV and macular atrophy, even after adjustment for age. These findings are relevant when counseling PXE patients on their visual prognosis.

The efficacy of corticosteroid-sparing immunomodulatory therapy in treating patients with central multifocal choroiditis.

PURPOSE: To evaluate the efficacy of corticosteroid-sparing immunomodulatory therapy (IMT) in patients with recurrent and/or sight-threatening central multifocal choroiditis (MFC). METHODS: This was a retrospective cohort study in a tertiary uveitis centre including all patients with MFC who have been treated with IMT for at least 12 months. Clinical data and imaging results were collected regarding the period prior to the start of IMT and at 3, 6, 12 and - where available - 24 months after the start of IMT. Main outcome measure was the number of annual recurrences of choroiditis with or without active choroidal neovascularization before and after the start of IMT. Secondary outcomes were the percentage of patients with (steroid-free) remission and the median time between the start of IMT and (steroid-free) remission. RESULTS: Thirty-two patients (39 eyes) were included. At the start of IMT, none of the patients were in (steroid-free) remission. At 24 months, the probability of achieving remission and steroid-free remission was 88,5% and 50%, respectively. The median time to achieve remission and steroid-free remission was 21 and 83 weeks, respectively. In 17 patients (20 eyes) with available clinical data and imaging results for ≥ 12 months prior to the start of IMT, the mean number of recurrences/year decreased significantly from 1.40 ± 0.81 at baseline to 0.49 ± 0.47 (p = 0.001) after the start of IMT. CONCLUSIONS: Preventive therapy with IMT should be considered in patients with recurrent and/or sight-threatening MFC to decrease the number of recurrences/year and to increase the prospects of achieving either remission or steroid-free remission.

Is arterial stiffness in the carotid artery associated with choroidal thinning in patients with pseudoxanthoma elasticum or controls?

PURPOSE: Patients with pseudoxanthoma elasticum (PXE) develop calcification of Bruch's membrane (BM) and choroidal thinning, as well as calcification of intracranial arteries, leading to arterial stiffness. We investigated whether arterial stiffness is associated with choroidal thinning in PXE patients, besides the presumed effect of BM calcification. METHODS: Cross-sectional study with 75 PXE patients and 40 controls. Macular choroidal thickness was measured using optical coherence tomography scans. Functional magnetic resonance imaging was used to calculate the pulsatility index (PI) of the carotid siphon as a measure of arterial stiffness. Associations between PI and choroidal thickness were investigated using linear mixed effects models adjusted for age and ocular axial length. Furthermore, we investigated choroidal thickness in relation to the presence of retinal pigment epithelium (RPE) atrophy, its topographical distribution and age. RESULTS: Median age was 58 years (IQR 53-66) in PXE patients and 62 years (IQR 56-67) in controls (p = 0.08). Pseudoxanthoma elasticum (PXE) patients had a thinner choroid than controls (138 µm versus 248 µm, p < 0.01). No association was observed between PI and choroidal thickness in PXE patients (ß = -1.6, 95% CI -59.4 to 54.5) nor in controls (ß =-47.6, 95% CI -129.7 to 31.9). In PXE patients, RPE atrophy was associated with a thinner choroid (p < 0.01). Also, the nasal choroid was thinner than the temporal choroid, and choroidal thickness already decreased with age in PXE eyes without RPE atrophy. CONCLUSION: There was no independent association between measures of arterial stiffness and choroidal thinning in PXE patients and controls. Probably, changes in BM lead to choroidal thinning in PXE.