ABSTRACT
PURPOSE: This study aims to explore genetic variants that potentially lead to outer retinal tubulation (ORT), estimate the prevalence of ORT in these candidate genes, and investigate the clinical etiology of ORT in patients with inherited retinal diseases (IRDs), with respect to each gene. DESIGN: Retrospective cohort study. METHODS: A retrospective cross-sectional review was conducted on 565 patients with molecular diagnoses of IRD, confirming the presence of ORT as noted in each patient's respective spectral-domain optical coherence tomography (SD-OCT) imaging. Using SD-OCT imaging, the presence of ORT was analyzed in relation to specific genetic variants and phenotypic characteristics. Outcomes included the observed ORT frequencies across two gene-specific cohorts: non- retinal pigment epithelium (RPE)-specific genes, and RPE-specific genes; and to investigate the analogous characteristics caused by variants in these genes. RESULTS: Among the 565 patients included in this study, 104 exhibited ORT on SD-OCT. We observed ORT frequencies among the following genes from our patient cohort: 100% (23/23) forCHM, 100%(2/2) forPNPLA6, 100% (4/4) forRCBTB1, 100% formtDNA[100% (4/4) forMT-TL1and 100% (1/1) formtDNAdeletion], 100% (1/1) forOAT, 95.2% (20/21) forCYP4V2, 72.7% (8/11) forCHMfemale carriers, 66.7% (2/3) forC1QTNF5, 57.1% (8/14) forPROM1, 53.8% (7/13) forPRPH2, 42.9% (3/7) forCERKL, 28.6% (2/7) forCDHR1, 20% (1/5) forRPE65, 4% (18/445) forABCA4.In contrast, ORT was not observed in any patients with photoreceptor-specific gene variants, such asRHO(n=13),USH2A(n=118),EYS(n=70),PDE6B(n=10),PDE6A(n=4),and others. CONCLUSION: These results illustrate a compelling association between the presence of ORT and IRDs caused by variants in RPE-specific genes, as well as non-RPE-specific genes. In contrast, IRDs caused by photoreceptor-specific genes are typically not associated with ORT occurrence. Further analysis revealed that ORT tends to manifest in IRDs with milder intraretinal pigment migration (IPM), a finding that is typically associated with RPE-specific genes. These findings regarding ORT, genetic factors, atrophic patterns in the fundus, and IPM provide valuable insight into the complex etiology of IRDs. Future prospective studies are needed to further explore the association and underlying mechanisms of ORT in these contexts.
ABSTRACT
Purpose: Choroidal thinning has been associated with reticular pseudodrusen (RPD) and ß-peripapillary atrophy (ß-PPA), which have been linked to normal-tension glaucoma (NTG). This analysis sought to determine whether RPD are independently associated with ß-PPA in early AMD patients. Secondary outcomes included the association of RPD and preexisting diagnosis of glaucoma, cup-to-disc ratio (CDR), subfoveal choroidal thickness (SFCT), and IOP. Methods: This prospective cross-sectional study examined 78 age- and sex-matched early AMD patients: 43 RPD patients (63 eyes) and 35 non-RPD patients (64 eyes). Exclusion criteria included advanced AMD, high myopia, and vitreoretinal conditions/surgery. RPD and non-RPD groups were identified by confocal scanning laser ophthalmoscopy. ß-PPA as well as CDR were graded on digital, nonstereoscopic fundus photos. SFCT was measured on spectral-domain optical coherence tomography for 69 patients (35 RPD and 34 non-RPD). IOP and glaucoma diagnosis were extracted from charts. Results: ß-PPA had a greater prevalence in RPD than non-RPD (44% vs. 19%, P = 0.002); however, this relationship was not significant when SFCT was added to the model (P = 0.150). A preexisting diagnosis of glaucoma (P = 0.156), CDR (P = 0.176), and IOP (P = 0.98) was not different between groups. Conclusions: RPD in early AMD are associated with presence of ß-PPA, but choroidal thickness is a confounder in this relationship. Because ß-PPA is a common finding in NTG, focusing on a potential shared pathway between RPD and NTG could improve the understanding of pathophysiology and expand therapies for each condition.