Genetic testing for inherited retinal degenerations: Triumphs and tribulations

Inherited retinal degenerations (IRDs) are a genotypically and phenotypically diverse group of conditions. Great strides have been made toward identifying the genetic basis for these conditions over the last 30 years—more than 270 different genes involved in syndromic and nonsyndromic forms of retinal dystrophies have now been identified. The identification of these genes and the improvement of clinical laboratory techniques have led to the identification of the genetic basis of disease in 56–76% of patients with IRDs through next generation sequencing and copy number variant analysis. Genetic testing is an essential part of clinical care for patients affected with IRDs and is required to confirm the diagnosis, understand the inheritance of the condition, and determine eligibility for gene‐specific treatments or clinical trials. Despite the success achieved in determining the genetic cause of these conditions, several challenges remain, which must be considered when providing genetic testing and genetic counseling to patients. For this reason, an integrated team of ophthalmic and genetic clinicians who are familiar with these challenges is necessary to provide optimal comprehensive care to these patients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162692/2/ajmgc31835.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162692/1/ajmgc31835_am.pd

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Directed evolution and in vivo function of plasminogen activator inhibitor-1.

Plasminogen Activator Inhibitor-1 (PAI-1) is a member of the Serine Protease Inhibitor (SERPIN) family and an important regulator of fibrinolysis. Although similar in structure and mechanism, SERPINs each have unique specificity for target proteases. PAI-1 is the physiologic inhibitor of tissue-type Plasminogen Activator (tPA) and urokinase Plasminogen Activator (uPA), which activate plasminogen to its active form, plasmin. However, PAI-1 spontaneously transitions to a stable, inactive conformation with a half-life of 2 hours under physiologic conditions. In addition, PAI-1 is sensitive to oxidative inactivation. However, the physiologic significance of the transition to latency and oxidative inactivation are unknown. Several PAI-1 variants with increased functional half-lives have been identified through random mutagenesis. This study investigated the in vivo effects of PAI-1 loss of latency using a mouse model. Furthermore, a random mutagenesis approach was used in order to find additional PAI-1 variants with altered functional properties. A transgene was engineered to direct widespread expression of a stable variant of murine PAI-1 from a hybrid CMV/chicken beta-actin promoter, and 10 independent transgenic lines were generated. Plasma PAI-1 levels in the founders ranged from 3.1+/-0.1 to 1268.8+/-717.0 ng/mL, and PAI-1 mRNA levels across tissues were elevated from 2-fold to 2245-fold over wild-type. No evidence of thrombosis was observed. The 2 founders with the highest plasma PAI-1 levels failed to produce viable transgenic offspring, suggesting that high expression of a stable PAI-1 variant may be lethal in mice. These mice may serve as a useful model for future investigations of PAI-1 function in vivo. In addition, a phage library of randomly mutagenized human PAI-1 molecules was screened for altered activity, such as resistance to oxidative inactivation and inhibition of neutrophil elastase. However, isolated clones failed to demonstrate the selected function in vitro, and false positives are a potential concern. Nevertheless, this approach highlighted the potential utility of a high-throughput screen of an exhaustive and unbiased pool of mutants. PAI-1 variants found through screening the phage library may reveal structural elements responsible for unique PAI-1 properties and may be useful for engineering mouse models that yield new insight into PAI-1 biology.Ph.D.Biological SciencesGeneticsMolecular biologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/126683/2/3276152.pd

Autoimmune retinopathy associated with monoclonal gammopathy of undetermined significance: a case report

Abstract Background Monoclonal gammopathy of undetermined significance (MGUS) is a plasma cell dyscrasia and precursor to multiple myeloma. It has known ocular manifestations, but has not previously been shown to have an association with autoimmune retinopathy. Case presentation A 57 year-old female presented with 1 year of progressive, bilateral, peripheral vision loss, photopsias, and nyctalopia. Her fundus examination and extensive ancillary testing were concerning for hereditary versus autoimmune retinopathy. The patient was found to have anti-retinal antibodies against carbonic anhydrase II and enolase proteins with a negative genetic retinal dystrophy panel. Malignancy work-up was negative, but the patient was diagnosed with MGUS, a premalignant condition. The patient was treated with immunosuppressive therapies, with rituximab demonstrating the most robust therapeutic response with respect to patient symptoms and ophthalmic testing. Conclusions MGUS should be considered as a potential etiology of autoimmune retinopathy in patients without other autoimmune or malignant disease processes. Immunosuppressive therapy may be helpful in limiting disease progression, with rituximab showing efficacy in retinopathy refractory to other agents.http://deepblue.lib.umich.edu/bitstream/2027.42/173590/1/12886_2020_Article_1423.pd

Clinical and imaging findings of choroideremia in a pediatric patient due to a novel frameshift mutation

Purpose: To describe the clinical characteristics, imaging findings and genetic testing results of a young simplex male with choroideremia. Observations: A 6-year-old Hispanic-Chinese male was referred to the retina clinic for peripheral retinal pigmentary changes observed in both eyes on routine exam. The patient has an unremarkable family history and developmental history. Best corrected visual acuity was 20/25 in both eyes. Optical coherence tomography demonstrated attenuation of the ellipsoid and interdigitation zones. Widefield fundus autofluorescence demonstrated nummular hypo-autofluorescence peripherally in both eyes. Genetic testing revealed a variant originally described as a variant of uncertain significance (VUS) a c. 1775_1814del (p.Glu592Valfs*44) identified in the CHM gene, which was reclassified as pathogenic following segregation analysis. The patient was diagnosed with choroideremia due to a CHM pathogenic variant. Conclusions: The multimodal imaging findings demonstrated here illustrate important clues to the diagnosis of Choroideremia in a simplex male

The Influence of Personality Type on Patient Outcome Measures and Therapeutic Alliance in Patients with Low Back Pain

Background: Low back pain (LBP) has been shown to have various biological, psychological, and social factors that affect prognosis. However, it is unclear how personality may influence self-reported outcome measures and therapeutic alliance (TA). Methods: Eysenck’s personality inventory was used to assess personality, while the numeric pain rating scale (NPRS), Oswestry Disability Index (ODI), Tampa Scale of Kinesiophobia (TSK), Global Rating of Change (GROC), and the Working Alliance Inventory (WAI) measured patient progress and relationship strength. All outcome measures were formulated in a single survey that both the therapist and patient completed electronically. Results: Sixty-seven patients with LBP and twenty-two licensed physical therapists participated. For personality measures, there was a significant positive correlation between neuroticism and GROC (rho = 0.295, p = 0.015) and a significant negative correlation between extraversion and WAI (rho = −0.243, p = 0.048). Significant correlations were found between ODI and TSK (rho = 0.462, p ≤ 0.001) and between ODI and GROC (rho = −0.416, p ≤ 0.001). A significant negative correlation was found between TSK and GROC (rho = −0.301, p = 0.013). Conclusions: Patients with higher levels of disability seemed to report higher levels of kinesiophobia and less overall improvement in physical therapy. Patients classified as neurotic reported higher levels of improvement while extraverted patients demonstrated a weaker therapeutic alliance with their therapist

Oxidative stress differentially impacts apical and basolateral secretion of angiogenic factors from human iPSC-derived retinal pigment epithelium cells

The retinal pigment epithelium (RPE) is a polarized monolayer that secretes growth factors and cytokines towards the retina apically and the choroid basolaterally. Numerous RPE secreted proteins have been linked to the pathogenesis of age-related macular degeneration (AMD). The purpose of this study was to determine the differential apical and basolateral secretome of RPE cells, and the effects of oxidative stress on directional secretion of proteins linked to AMD and angiogenesis. Tandem mass tag spectrometry was used to profile proteins in human iPSC-RPE apical and basolateral conditioned media. Changes in secretion after oxidative stress induced by H(2)O(2) or tert-butyl hydroperoxide (tBH) were investigated by ELISA and western analysis. Out of 926 differentially secreted proteins, 890 (96%) were more apical. Oxidative stress altered the secretion of multiple factors implicated in AMD and neovascularization and promoted a pro-angiogenic microenvironment by increasing the secretion of pro-angiogenic molecules (VEGF, PTN, and CRYAB) and decreasing the secretion of anti-angiogenic molecules (PEDF and CFH). Apical secretion was impacted more than basolateral for PEDF, CRYAB and CFH, while basolateral secretion was impacted more for VEGF, which may have implications for choroidal neovascularization. This study lays a foundation for investigations of dysfunctional RPE polarized protein secretion in AMD and other chorioretinal degenerative disorders

Allelic heterogeneity and genetic modifier loci contribute to clinical variation in males with X-linked retinitis pigmentosa due to RPGR mutations.

Mutations in RPGR account for over 70% of X-linked retinitis pigmentosa (XlRP), characterized by retinal degeneration and eventual blindness. The clinical consequences of RPGR mutations are highly varied, even among individuals with the same mutation: males demonstrate a wide range of clinical severity, and female carriers may or may not be affected. This study describes the phenotypic diversity in a cohort of 98 affected males from 56 families with RPGR mutations, and demonstrates the contribution of genetic factors (i.e., allelic heterogeneity and genetic modifiers) to this diversity. Patients were categorized as grade 1 (mild), 2 (moderate) or 3 (severe) according to specific clinical criteria. Patient DNAs were genotyped for coding SNPs in 4 candidate modifier genes with products known to interact with RPGR protein: RPGRIP1, RPGRIP1L, CEP290, and IQCB1. Family-based association testing was performed using PLINK. A wide range of clinical severity was observed both between and within families. Patients with mutations in exons 1-14 were more severely affected than those with ORF15 mutations, and patients with predicted null alleles were more severely affected than those predicted to make RPGR protein. Two SNPs showed association with severe disease: the minor allele (N) of I393N in IQCB1 (p = 0.044) and the common allele (R) of R744Q in RPGRIP1L (p = 0.049). These data demonstrate that allelic heterogeneity contributes to phenotypic diversity in XlRP and suggest that this may depend on the presence or absence of RPGR protein. In addition, common variants in 2 proteins known to interact with RPGR are associated with severe disease in this cohort