Retinal Dystrophies Associated With Peripherin-2: Genetic Spectrum and Novel Clinical Observations in 241 Patients.

Purpose: To describe the clinical, electrophysiological and genetic spectrum of inherited retinal diseases associated with variants in the PRPH2 gene. Methods: A total of 241 patients from 168 families across 15 sites in 9 countries with pathogenic or likely pathogenic variants in PRPH2 were included. Records were reviewed for age at symptom onset, visual acuity, full-field ERG, fundus colour photography, fundus autofluorescence (FAF), and SD-OCT. Images were graded into six phenotypes. Statistical analyses were performed to determine genotype-phenotype correlations. Results: The median age at symptom onset was 40 years (range, 4-78 years). FAF phenotypes included normal (5%), butterfly pattern dystrophy, or vitelliform macular dystrophy (11%), central areolar choroidal dystrophy (28%), pseudo-Stargardt pattern dystrophy (41%), and retinitis pigmentosa (25%). Symptom onset was earlier in retinitis pigmentosa as compared with pseudo-Stargardt pattern dystrophy (34 vs 44 years; P = 0.004). The median visual acuity was 0.18 logMAR (interquartile range, 0-0.54 logMAR) and 0.18 logMAR (interquartile range 0-0.42 logMAR) in the right and left eyes, respectively. ERG showed a significantly reduced amplitude across all components (P < 0.001) and a peak time delay in the light-adapted 30-Hz flicker and single-flash b-wave (P < 0.001). Twenty-two variants were novel. The central areolar choroidal dystrophy phenotype was associated with 13 missense variants. The remaining variants showed marked phenotypic variability. Conclusions: We described six distinct FAF phenotypes associated with variants in the PRPH2 gene. One FAF phenotype may have multiple ERG phenotypes, demonstrating a discordance between structure and function. Given the vast spectrum of PRPH2 disease our findings are useful for future clinical trials.

Natural history and biomarkers of KCNV2-associated retinopathy.

BACKGROUND: KCNV2-associated retinopathy is an autosomal recessive inherited retinal disease classically named cone dystrophy with supernormal rod response (CDSRR). This study aims to identify the best biomarker for evaluating the condition. METHODS: A retrospective review of eight patients from seven families with genetically confirmed KCNV2-associated retinopathy was performed. The best corrected visual acuity (BCVA), full-field electroretinogram (ffERG), pattern ERG (pERG), fundus imaging: retinal photograph and fundus autofluorescence (FAF), and optical coherence tomography (OCT) were analysed. RESULTS: There was a disproportionate increase in b-wave amplitude with a relatively small light intensity increase, especially between the two dimmest stimuli of DA 0.002 and 0.01 (-2.7 and -2.0 log cd.s/m2 ). The a-wave amplitude was normal. The a-wave peak time was delayed in all stimuli. The b-wave peak time was delayed compared to normal, but the gap tightened as intensity increased. The b:a wave ratio was above or at the upper limit for the reference values. FAF bull's eye maculopathy pattern was prominent and variable foveal disruption on OCT was apparent in all patients. Legal blindness was reached before the age of 25. CONCLUSIONS: We identified three potential electrophysiology biomarkers to assist in evaluating future therapies: the disproportionate b-wave amplitude jump, delayed a-wave and b-wave peak time, and the higher than normal b:a wave ratio. Any of these biomarkers found with photoreceptor ellipsoid zone foveal-perifoveal disruption should prompt consideration for KCNV2 retinopathy. The BCVA natural history data suggests the probable optimum therapeutic window in the first three decades of life.

What is the power of a genomic multidisciplinary team approach? A systematic review of implementation and sustainability.

Due to the increasing complexity of genomic data interpretation, and need for close collaboration with clinical, laboratory, and research expertise, genomics often requires a multidisciplinary team (MDT) approach. This systematic review aims to establish the evidence for effectiveness of the genomic multidisciplinary team, and the implementation components of this model that can inform precision care. MEDLINE, Embase and PsycINFO databases were searched in 2022 and 2023. We included qualitative and quantitative studies of the genomic MDT, including observational and cohort studies, for diagnosis and management, and implementation outcomes of effectiveness, adoption, efficiency, safety, and acceptability. A narrative synthesis was mapped against the Genomic Medicine Integrative Research framework. 1530 studies were screened, and 17 papers met selection criteria. All studies pointed towards the effectiveness of the genomic MDT approach, with 10-78% diagnostic yield depending on clinical context, and an increased yield of 6-25% attributed to the MDT. The genomic MDT was found to be highly efficient in interpretation of variants of uncertain significance, timeliness for a rapid result, made a significant impact on management, and was acceptable for adoption by a wide variety of subspecialists. Only one study utilized an implementation science based approach. The genomic MDT approach appears to be highly effective and efficient, facilitating higher diagnostic rates and improved patient management. However, key gaps remain in health systems readiness for this collaborative model, and there is a lack of implementation science based research especially addressing the cost, sustainability, scale up, and equity of access.

A founder variant expands the phenotype of WNT7B-related PDAC syndrome.

Pulmonary hypoplasia, Diaphragmatic anomalies, Anophthalmia/microphthalmia, and Cardiac defects (PDAC) syndrome is a genetically heterogeneous multiple congenital malformation syndrome. Although pathogenic variants in RARB and STRA6 are established causes of PDAC, many PDAC cases remain unsolved at the molecular level. Recently, we proposed biallelic WNT7B variants as a novel etiology based on several families with typical features of PDAC syndrome albeit with variable expressivity. Here, we report three patients from two families that share a novel founder variant in WNT7B (c.739C > T; Arg247Trp). The phenotypic expression of this variant ranges from typical PDAC features to isolated genitourinary anomalies. Similar to previously reported PDAC-associated WNT7B variants, this variant was found to significantly impair WNT7B signaling activity further corroborating its proposed pathogenicity. This report adds further evidence to WNT7B-related PDAC and expands its variable expressivity.

Managing the apparently blind child presenting in the first year of life: A review.

Severe vision impairment and blindness in childhood have a significant health burden on the child, family and society. This review article seeks to provide a structured framework for managing the apparently blind child presenting in the first year of life, starting from a comprehensive history and examination. Different investigation modalities and the increasingly important role of genetics will also be described, in addition to common causes of severe vision impairment. Crucially, a systematic approach to the blind infant is key to correct diagnoses and timely management. Incorrect diagnoses can be costly to all involved, however it is important to note that diagnoses can change with ongoing follow-up and investigations. Furthermore, the modern age of ophthalmology requires a multi-disciplinary approach and close collaboration with specialists including paediatricians, neurologists and geneticists, in addition to rehabilitation and low vision services, to ensure the best care for these vulnerable infants.

AAV capsid bioengineering in primary human retina models.

Adeno-associated viral (AAV) vector-mediated retinal gene therapy is an active field of both pre-clinical as well as clinical research. As with other gene therapy clinical targets, novel bioengineered AAV variants developed by directed evolution or rational design to possess unique desirable properties, are entering retinal gene therapy translational programs. However, it is becoming increasingly evident that predictive preclinical models are required to develop and functionally validate these novel AAVs prior to clinical studies. To investigate if, and to what extent, primary retinal explant culture could be used for AAV capsid development, this study performed a large high-throughput screen of 51 existing AAV capsids in primary human retina explants and other models of the human retina. Furthermore, we applied transgene expression-based directed evolution to develop novel capsids for more efficient transduction of primary human retina cells and compared the top variants to the strongest existing benchmarks identified in the screening described above. A direct side-by-side comparison of the newly developed capsids in four different in vitro and ex vivo model systems of the human retina allowed us to identify novel AAV variants capable of high transgene expression in primary human retina cells.

A natural history study of autosomal dominant GUCY2D-associated cone-rod dystrophy.

PURPOSE: To describe the natural history of autosomal dominant (AD) GUCY2D-associated cone-rod dystrophies (CRDs), and evaluate associated structural and functional biomarkers. METHODS: Retrospective analysis was conducted on 16 patients with AD GUCY2D-CRDs across two sites. Assessments included central macular thickness (CMT) and length of disruption to the ellipsoid zone (EZ) via optical coherence tomography (OCT), electroretinography (ERG) parameters, best corrected visual acuity (BCVA), and fundus autofluorescence (FAF). RESULTS: At first visit, with a mean age of 30 years (range 5-70 years), 12 patients had a BCVA below Australian driving standard (LogMAR ≥ 0.3 bilaterally), and 1 patient was legally blind (LogMAR ≥ 1). Longitudinal analysis demonstrated a deterioration of LogMAR by - 0.019 per year (p < 0.001). This accompanied a reduction in CMT of - 1.4 µm per year (p < 0.0001), lengthened EZ disruption by 42 µm per year (p = < 0.0001) and increased area of FAF by 0.05 mm2 per year (p = 0.027). Similarly, cone function decreased with increasing age, as demonstrated by decreasing b-wave amplitude of the light-adapted 30 Hz flicker and fused flicker (p = 0.005 and p = 0.018, respectively). Reduction in CMT and increased EZ disruption on OCT were associated with functional changes including poorer BCVA and decreased cone function on ERG. CONCLUSION: We have described the natural long-term decline in vision and cone function associated with mutations in GUCY2D and identified a set of functional and structural biomarkers that may be useful as outcome parameters for future therapeutic clinical trials.

Prevalence of Glaucoma Following Paediatric Cataract Surgery in an Australian Tertiary Referral Centre.

Purpose: Secondary glaucoma following childhood cataract surgery remains the most common complication in the paediatric population. This study aimed to determine the incidence, time to progression and risk factors associated with the development of secondary glaucoma following childhood cataract surgery in a paediatric population. Outcome measures were the detection of secondary glaucoma, postoperative time frame to development of glaucoma and risk factors in its development. Patients and Methods: A retrospective case series was conducted between 2003 and 2017 at a tertiary children's hospital in Sydney. The patient population included those 16 years or less of age who underwent congenital cataract extraction, with or without an intraocular lens implantation and who had been followed up for a minimum of six months following surgery. Patients were excluded if they had cataract aetiology other than congenital idiopathic cataract. Multivariate Cox Regression analysis was used to determine relevant risk factors. Results: A total of 320 eyes in 216 patients were included in the study. Secondary glaucoma developed in 11.9% of eyes. In those that developed secondary glaucoma, the average time to onset from surgery was 3.2 years (median 2.75 years). The mean age of diagnosis of secondary glaucoma was 4.58 years (median 3.5 years, range 2.5 months to 13.23 years). Microcornea was the only adverse characteristic significantly associated with an increased risk of secondary glaucoma (HR 6.30, p 0.003). Conclusion: Despite modern surgical techniques, glaucoma remains a significant long-term sequela in children following cataract surgery.

The health care and societal costs of inherited retinal diseases in Australia: a microsimulation modelling study.

OBJECTIVES: To estimate the health care and societal costs of inherited retinal diseases (IRDs) in Australia. DESIGN, SETTING, PARTICIPANTS: Microsimulation modelling study based on primary data - collected in interviews of people with IRDs who had ophthalmic or genetic consultations at the Children's Hospital at Westmead or the Save Sight Institute (both Sydney) during 1 January 2019 - 31 December 2020, and of their carers and spouses - and linked Medicare Benefits Schedule (MBS) and Pharmaceutical Benefits Schedule (PBS) data. MAIN OUTCOME MEASURES: Annual and lifetime costs for people with IRDs and for their carers and spouses, grouped by payer (Australian government, state governments, individuals, private health insurance) and type (health care costs; societal costs: social support, National Disability Insurance Scheme (NDIS), income and taxation, costs associated with caring for family members with IRDs); estimated annual national cost of IRDs. RESULTS: Ninety-four people (74 adults, 20 people under 18 years; 55 girls and women [59%]) and 30 carers completed study surveys (participation rate: adults, 66%; children, 66%; carers, 63%). Total estimated lifetime cost was $5.2 million per person with an IRD, of which 87% were societal and 13% health care costs. The three highest cost items were lost income for people with IRDs ($1.4 million), lost income for their carers and spouses ($1.1 million), and social spending by the Australian government (excluding NDIS expenses: $1.0 million). Annual costs were twice as high for people who were legally blind as for those with less impaired vision ($83 910 v $41 357 per person). The estimated total annual cost of IRDs in Australia was $781 million to $1.56 billion. CONCLUSION: As the societal costs associated with IRDs are much larger than the health care costs, both contributors should be considered when assessing the cost-effectiveness of interventions for people with IRDs. The increasing loss of income across life reflects the impact of IRDs on employment and career opportunities.

IMPDH1-associated autosomal dominant retinitis pigmentosa: natural history of novel variant Lys314Gln and a comprehensive literature search.

BACKGROUND: Inosine monophosphate dehydrogenase (IMPDH) is a key regulatory enzyme in the de novo synthesis of the purine base guanine. Mutations in the inosine monophosphate dehydrogenase 1 gene (IMPDH1) are causative for RP10 autosomal dominant retinitis pigmentosa (adRP). This study reports a novel variant in a family with IMPDH1-associated retinopathy. We also performed a comprehensive review of all reported IMPDH1 disease causing variants with their associated phenotype. MATERIALS AND METHODS: Multimodal imaging and functional studies documented the phenotype including best-corrected visual acuity (BCVA), fundus photograph, fundus autofluorescence (FAF), full field electroretinogram (ffERG), optical coherence tomography (OCT) and visual field (VF) data were collected. A literature search was performed in the PubMed and LOVD repositories. RESULTS: We report 3 cases from a 2-generation family with a novel heterozygous likely pathogenic variant p. (Lys314Gln) (exon 10). The ophthalmic phenotype showed diffuse outer retinal atrophy with mild pigmentary changes with sparse pigmentary changes. FAF showed early macular involvement with macular hyperautofluorescence (hyperAF) surrounded by hypoAF. Foveal ellipsoid zone island can be found in the youngest patient but not in the older ones. The literature review identified a further 56 heterozygous, 1 compound heterozygous, and 2 homozygous variant. The heterozygous group included 43 missense, 3 in-frame, 1 nonsense, 2 frameshift, 1 synonymous, and 6 intronic variants. Exon 10 was noted as a hotspot harboring 18 variants. CONCLUSIONS: We report a novel IMPDH1 variant. IMPDH1-associated retinopathy presents most frequently in the first decade of life with early macular involvement.

Spectrum of ocular disease in children aged between 0 and 3 years at an Australian paediatric tertiary hospital.

BACKGROUND: Childhood ocular disease can be a significant health burden to the child, family and society. Previous studies have examined the spectrum of paediatric ocular disease presenting to tertiary hospitals; however, these studies have broader age ranges, smaller sample sizes, and are largely based in developing countries. This study aims to assess the spectrum of ocular disease in the first 3 years of life presenting to the eye department of an Australian tertiary paediatric hospital. METHODS: The records of 3337 children who had their initial presentation at the eye clinic between the age of 0 and 36 months were reviewed, spanning 6.5 years from 1st July 2012 to 31st December 2018. RESULTS: The most common primary diagnoses overall were strabismic amblyopia (6.0%), retinopathy of prematurity (5.0%) and nasolacrimal duct obstruction (4.5%). Bilateral visual impairment was more common in younger children, while unilateral visual impairment was more common in older children. The proportion of all children presenting with visual impairment was 10.3%, with 5.7% of all children presenting with bilateral visual impairment and 4.6% presenting with unilateral visual impairment. In children with visual impairment, the most common sites of primary abnormality were lens (21.4%), retina (17.3%), and cerebral and visual pathways (12.1%). The most common primary diagnoses in children with visual impairment were cataract (21.4%), strabismic amblyopia (9.3%) and retinoblastoma (6.5%). CONCLUSIONS: The spectrum of eye disease and vision impairment presenting in the first 3 years of life facilitates health care planning, greater community education about vision impairment and importance of early intervention, and guidance for appropriate resource allocation. Health systems can apply these findings to aid in early identification and intervention to reduce preventable blindness and institute appropriate rehabilitation services.

Early recognition of CLN3 disease facilitated by visual electrophysiology and multimodal imaging.

BACKGROUND: Neuronal ceroid lipofuscinosis is a group of neurodegenerative disorders with varying visual dysfunction. CLN3 is a subtype which commonly presents with visual decline. Visual symptomatology can be indistinct making early diagnosis difficult. This study reports ocular biomarkers of CLN3 patients to assist clinicians in early diagnosis, disease monitoring, and future therapy. METHODS: Retrospective review of 5 confirmed CLN3 patients in our eye clinic. Best corrected visual acuity (BCVA), electroretinogram (ERG), ultra-widefield (UWF) fundus photography and fundus autofluorescence (FAF), and optical coherence tomography (OCT) studies were undertaken. RESULTS: Five unrelated children, 4 females and 1 male, with median age of 6.2 years (4.6-11.7) at first assessment were investigated at the clinic from 2016 to 2021. Four homozygous and one heterozygous pathogenic CLN3 variants were found. Best corrected visual acuities (BCVAs) ranged from 0.18 to 0.88 logMAR at first presentation. Electronegative ERGs were identified in all patients. Bull's eye maculopathies found in all patients. Hyper-autofluorescence ring surrounding hypo-autofluorescence fovea on FAF was found. Foveal ellipsoid zone (EZ) disruptions were found in all patients with additional inner and outer retinal microcystic changes in one patient. Neurological problems noted included autism, anxiety, motor dyspraxia, behavioural issue, and psychomotor regression. CONCLUSIONS: CLN3 patients presented at median age 6.2 years with visual decline. Early onset maculopathy with an electronegative ERG and variable cognitive and motor decline should prompt further investigations including neuropaediatric evaluation and genetic assessment for CLN3 disease. The structural parameters such as EZ and FAF will facilitate ocular monitoring.

Comprehensive characterization of fetal and mature retinal cell identity to assess the fidelity of retinal organoids.

Characterizing cell identity in complex tissues such as the human retina is essential for studying its development and disease. While retinal organoids derived from pluripotent stem cells have been widely used to model development and disease of the human retina, there is a lack of studies that have systematically evaluated the molecular and cellular fidelity of the organoids derived from various culture protocols in recapitulating their in vivo counterpart. To this end, we performed an extensive meta-atlas characterization of cellular identities of the human eye, covering a wide range of developmental stages. The resulting map uncovered previously unknown biomarkers of major retinal cell types and those associated with cell-type-specific maturation. Using our retinal-cell-identity map from the fetal and adult tissues, we systematically assessed the fidelity of the retinal organoids in mimicking the human eye, enabling us to comprehensively benchmark the current protocols for retinal organoid generation.

Bi-allelic variants in WNT7B disrupt the development of multiple organs in humans.

BACKGROUND: Pulmonary hypoplasia, Diaphragmatic anomalies, Anophthalmia/microphthalmia and Cardiac defects delineate the PDAC syndrome. We aim to identify the cause of PDAC syndrome in patients who do not carry pathogenic variants in RARB and STRA6, which have been previously associated with this disorder. METHODS: We sequenced the exome of patients with unexplained PDAC syndrome and performed functional validation of candidate variants. RESULTS: We identified bi-allelic variants in WNT7B in fetuses with PDAC syndrome from two unrelated families. In one family, the fetus was homozygous for the c.292C>T (p.(Arg98*)) variant whereas the fetuses from the other family were compound heterozygous for the variants c.225C>G (p.(Tyr75*)) and c.562G>A (p.(Gly188Ser)). Finally, a molecular autopsy by proxy in a consanguineous couple that lost two babies due to lung hypoplasia revealed that both parents carry the p.(Arg98*) variant. Using a WNT signalling canonical luciferase assay, we demonstrated that the identified variants are deleterious. In addition, we found that wnt7bb mutant zebrafish display a defect of the swimbladder, an air-filled organ that is a structural homolog of the mammalian lung, suggesting that the function of WNT7B has been conserved during evolution for the development of these structures. CONCLUSION: Our findings indicate that defective WNT7B function underlies a form of lung hypoplasia that is associated with the PDAC syndrome, and provide evidence for involvement of the WNT-ß-catenin pathway in human lung, tracheal, ocular, cardiac, and renal development.

Eye Abnormalities in Children with Fetal Alcohol Spectrum Disorders: A Systematic Review.

PURPOSE: Although eye abnormalities are reported in fetal alcohol spectrum disorders (FASD), no systematic review based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines has been undertaken. Our aim was to document the range and prevalence of eye abnormalities reported in children with prenatal alcohol exposure (PAE) and/or FASD. METHODS: Searches of electronic databases and manual searches. Eligible articles were observational studies in children with PAE and/or FASD; peer reviewed journal articles in the English language; and studies reporting quantitative or frequency data on functional/structural eye abnormalities. Pooled prevalence, odds ratio, and mean differences were calculated. RESULTS: Of the 1,068 retrieved articles 36 were eligible, including articles on children with diagnosed fetal alcohol syndrome/FASD (N = 31); PAE (N = 3); and FASD or PAE without FASD (N = 2). Structural and functional eye abnormalities were identified, the most prevalent being short palpebral fissure length (66.1%), visual impairment (55.5%), epicanthus (53.5%), subnormal stereoacuity (53.0%), abnormal retinal tortuosity (50.5%), impaired fixation ability (33.3%), telecanthus (31.7%), optic nerve hypoplasia (30.2%), and small optic discs (27.0%). Compared to non-exposed controls, strabismus, subnormal vision, ptosis, short palpebral fissure length, microphthalmos, smaller optic disc area, and retinal vessel tortuosity were more prevalent in children with FASD. CONCLUSIONS: Examination of eyes and vision should be considered in children with PAE and suspected or diagnosed FASD to enable early identification and optimal management. This first comprehensive, systematic literature review demonstrates the variety and frequency of eye abnormalities reported in PAE/FASD.

Survey of perspectives of people with inherited retinal diseases on ocular gene therapy in Australia.

Many gene therapies are in development for treating people with inherited retinal diseases (IRD). We hypothesized that potential recipients of gene therapy would have knowledge gaps regarding treatment. We aimed to assess knowledge, attitudes, and perceptions of genetic therapies among potential recipients with IRD, using a novel instrument we designed (Attitudes to Gene Therapy-Eye (AGT-Eye)) and their associations with demographic data, self-reported visual status, and tools assessing quality of life and attitudes toward clinical trials using a community-based cross-sectional survey of Australian adults with IRD. AGT-Eye, overall quality of life EQ-5D-5L, National Eye Institute Visual Functioning Questionnaire (NEI-VFQ-25) and Patient Attitudes to Clinical Trials (PACT-22) instruments were administered. Six hundred and eighty-one people completed the study, 51.7% women of mean age 53.5 years (SD ± 15.8). Most participants (91.6%) indicated they would likely accept gene therapy if it was available to them or family members. However, only 28.3% agreed that they had good knowledge of gene therapy. Most obtained information about gene therapy from the internet (49.3%). Respondents with post-graduate degrees scored highest compared to other educational levels on methods (p < 0.001) and outcomes (p = 0.003) and were more likely to see economic value of treatment (p = 0.043). Knowledge gaps were present regarding methods and outcomes of gene therapy. This survey has shown high level of interest in the IRD community for gene therapies, and highlights areas for improved clinician and patient education.

Patient-Reported Health-Related Quality of Life in Individuals with Inherited Retinal Diseases.

Purpose: To evaluate the impact of inherited retinal diseases (IRDs) on quality of life (QoL) using multiattributable health utilities derived from primary patient data. Design: Cross-sectional observational study. Participants: Seventy adult patients (mean age, 42.7 years) with IRD recruited from state-wide services in Australia. Methods: Health utility values were calculated from the Assessment of Quality of Life 8-Dimension (AQoL-8D). Linear regressions were used to analyze the relationship between the 25-item and 39-item National Eye Institute Visual Function Questionnaires (NEI-VFQ-25 and NEI-VFQ-39, respectively) and health utilities from the AQoL-8D. Main Outcome Measures: The AQoL-8D utility values were compared between the IRD cohort and population norms. Regressions were used to determine explanatory power of the NEI-VFQ-25 and NEI-VFQ-39 for health utilities from the AQoL-8D. Results: Average health-related utility for patients with IRD was 0.58, significantly lower than population norms of 0.80. The IRD patient scores were significantly lower than population norms for all 8 domains of the AQoL-8D. Regressions showed a statistically significant relationship between the NEI-VFQ-39 and AQoL-8D, with the NEI-VFQ-39 and other clinical data explaining up to 73% of the variation in AQoL-8D values and 69% of the variation in the NEI-VFQ-25 values. Conclusions: Patients with IRD have significantly lower utility values across all dimensions of QoL, with the largest differences in independent living, senses, and relationships. The NEI-VFQ-25 and NEI-VFQ-39 are highly correlated with overall AQoL-8D utilities and, combined with other data, can reasonably estimate QoL utilities required for cost-effectiveness studies.

Whole Genome Sequencing, Focused Assays and Functional Studies Increasing Understanding in Cryptic Inherited Retinal Dystrophies.

The inherited retinal dystrophies (IRDs) are a clinically and genetically complex group of disorders primarily affecting the rod and cone photoreceptors or other retinal neuronal layers, with emerging therapies heralding the need for accurate molecular diagnosis. Targeted capture and panel-based strategies examining the partial or full exome deliver molecular diagnoses in many IRD families tested. However, approximately one in three families remain unsolved and unable to obtain personalised recurrence risk or access to new clinical trials or therapy. In this study, we investigated whole genome sequencing (WGS), focused assays and functional studies to assist with unsolved IRD cases and facilitate integration of these approaches to a broad molecular diagnostic clinical service. The WGS approach identified variants not covered or underinvestigated by targeted capture panel-based clinical testing strategies in six families. This included structural variants, with notable benefit of the WGS approach in repetitive regions demonstrated by a family with a hybrid gene and hemizygous missense variant involving the opsin genes, OPN1LW and OPN1MW. There was also benefit in investigation of the repetitive GC-rich ORF15 region of RPGR. Further molecular investigations were facilitated by focused assays in these regions. Deep intronic variants were identified in IQCB1 and ABCA4, with functional RNA based studies of the IQCB1 variant revealing activation of a cryptic splice acceptor site. While targeted capture panel-based methods are successful in achieving an efficient molecular diagnosis in a proportion of cases, this study highlights the additional benefit and clinical value that may be derived from WGS, focused assays and functional genomics in the highly heterogeneous IRDs.