Making glaucoma genetic studies more diverse.

Although the blinding eye disease glaucoma is more common in people of African ancestry, previous genetic studies predominantly involved European subjects. In this issue of Cell, O'Brien et al. report a genome-wide association study for glaucoma in individuals of African ancestry, showing overlap with European studies and refining an African polygenic risk score.

Noncoding variants alter GATA2 expression in rhombomere 4 motor neurons and cause dominant hereditary congenital facial paresis.

Hereditary congenital facial paresis type 1 (HCFP1) is an autosomal dominant disorder of absent or limited facial movement that maps to chromosome 3q21-q22 and is hypothesized to result from facial branchial motor neuron (FBMN) maldevelopment. In the present study, we report that HCFP1 results from heterozygous duplications within a neuron-specific GATA2 regulatory region that includes two enhancers and one silencer, and from noncoding single-nucleotide variants (SNVs) within the silencer. Some SNVs impair binding of NR2F1 to the silencer in vitro and in vivo and attenuate in vivo enhancer reporter expression in FBMNs. Gata2 and its effector Gata3 are essential for inner-ear efferent neuron (IEE) but not FBMN development. A humanized HCFP1 mouse model extends Gata2 expression, favors the formation of IEEs over FBMNs and is rescued by conditional loss of Gata3. These findings highlight the importance of temporal gene regulation in development and of noncoding variation in rare mendelian disease.

Is the disease risk and penetrance in Leber hereditary optic neuropathy actually low?

Pedigree analysis showed that a large proportion of Leber hereditary optic neuropathy (LHON) family members who carry a mitochondrial risk variant never lose vision. Mitochondrial haplotype appears to be a major factor influencing the risk of vision loss from LHON. Mitochondrial variants, including m.14484T>C and m.11778G>A, have been added to gene arrays, and thus many patients and research participants are tested for LHON mutations. Analysis of the UK Biobank and Australian cohort studies found more than 1 in 1,000 people in the general population carry either the m.14484T>C or the m.11778G>A LHON variant. None of the subset of carriers examined had visual acuity at 20/200 or worse, suggesting a very low penetrance of LHON. Haplogroup analysis of m.14484T>C carriers showed a high rate of haplogroup U subclades, previously shown to have low penetrance in pedigrees. Penetrance calculations of the general population are lower than pedigree calculations, most likely because of modifier genetic factors. This Matters Arising Response paper addresses the Watson et al. (2022) Matters Arising paper, published concurrently in The American Journal of Human Genetics.

Danish heritable retinoblastoma survivors' perspectives on reproductive choices: "It's important for me, not to pass on this condition".

Despite reporting an overall normal life, survivors of heritable retinoblastoma face numerous physical and psychosocial issues. In particular, reproductive decision-making is often complex and difficult. This study aims to examine survivors' reflections on passing on heritable retinoblastoma to their children, how survivors approach their reproductive choices, and how the healthcare system can optimize counseling and support. Semi-structured interviews with Danish adult survivors of heritable retinoblastoma were qualitatively analyzed to explore their experiences. Participants were recruited from the Retinoblastoma Survivorship Clinic, Aarhus University Hospital, Denmark. Thematic data analysis was conducted followed by a condensing process specifically for the subthemes relating to reproductive choices. A common subtheme for all participants was a strong wish to avoid passing on retinoblastoma to their children. The participants emphasized the various medical, practical, emotional, and moral issues impacting their final reproductive choice in the process of family planning to conceive a child unaffected by retinoblastoma. Some had no option other than to conceive naturally and hope for an unaffected baby; while others weighed the pros and cons of choosing natural conception with prenatal testing and then considering termination of pregnancy (in case of an affected fetus) versus choosing fertility treatment with preimplantation genetic testing to achieve an unaffected pregnancy. Several participants underlined the complexity of their decisions, and also expressed feelings of guilt, both toward their affected child, and guilt for putting their partner through many difficult decisions and obstacles due to their genetic condition. Our findings demonstrate how one family-planning decision is not unequivocally "better" or easier than another. Healthcare professionals must provide the necessary information and tools to support the individual's unique decision-making process. Survivors' autonomy and individual needs, as well as the numerous and diverse aspects of heritable retinoblastoma, should be carefully considered.

Thrombospondin 1 missense alleles induce extracellular matrix protein aggregation and TM dysfunction in congenital glaucoma.

Glaucoma is a highly heritable disease that is a leading cause of blindness worldwide. Here, we identified heterozygous thrombospondin 1 (THBS1) missense alleles altering p.Arg1034, a highly evolutionarily conserved amino acid, in 3 unrelated and ethnically diverse families affected by congenital glaucoma, a severe form of glaucoma affecting children. Thbs1R1034C-mutant mice had elevated intraocular pressure (IOP), reduced ocular fluid outflow, and retinal ganglion cell loss. Histology revealed an abundant, abnormal extracellular accumulation of THBS1 with abnormal morphology of juxtacanalicular trabecular meshwork (TM), an ocular tissue critical for aqueous fluid outflow. Functional characterization showed that the THBS1 missense alleles found in affected individuals destabilized the THBS1 C-terminus, causing protein misfolding and extracellular aggregation. Analysis using a range of amino acid substitutions at position R1034 showed that the extent of aggregation was correlated with the change in protein-folding free energy caused by variations in amino acid structure. Extracellular matrix (ECM) proteins, especially fibronectin, which bind to THBS1, also accumulated within THBS1 deposits. These results show that missense variants altering THBS1 p.Arg1034 can cause elevated IOP through a mechanism involving impaired TM fluid outflow in association with accumulation of aggregated THBS1 in the ECM of juxtacanalicular meshwork with altered morphology.

Pathogenic genetic variants identified in Australian families with paediatric cataract.

OBJECTIVE: Paediatric (childhood or congenital) cataract is an opacification of the normally clear lens of the eye and has a genetic basis in at least 18% of cases in Australia. This study aimed to replicate clinical gene screening to identify variants likely to be causative of disease in an Australian patient cohort. METHODS AND ANALYSIS: Sixty-three reported isolated cataract genes were screened for rare coding variants in 37 Australian families using genome sequencing. RESULTS: Disease-causing variants were confirmed in eight families with variant classification as 'likely pathogenic'. This included novel variants PITX3 p.(Ter303LeuextTer100), BFSP1 p.(Glu375GlyfsTer2), and GJA8 p.(Pro189Ser), as well as, previously described variants identified in genes GJA3, GJA8, CRYAA, BFSP1, PITX3, COL4A1 and HSF4. Additionally, eight variants of uncertain significance with evidence towards pathogenicity were identified in genes: GJA3, GJA8, LEMD2, PRX, CRYBB1, BFSP2, and MIP. CONCLUSION: These findings expand the genotype-phenotype correlations of both pathogenic and benign variation in cataract-associated genes. They further emphasise the need to develop additional evidence such as functional assays and variant classification criteria specific to paediatric cataract genes to improve interpretation of variants and molecular diagnosis in patients.

Diagnostic yield of candidate genes in an Australian corneal dystrophy cohort.

Corneal dystrophies describe a clinically and genetically heterogeneous group of inherited disorders. The International Classification of Corneal Dystrophies (IC3D) lists 22 types of corneal dystrophy, 17 of which have been demonstrated to result from pathogenic variants in 19 identified genes. In this study, we investigated the diagnostic yield of genetic testing in a well-characterised cohort of 58 individuals from 44 families with different types of corneal dystrophy. Individuals diagnosed solely with Fuchs endothelial corneal dystrophy were excluded. Clinical details were obtained from the treating ophthalmologist. Participants and their family members were tested using a gene candidate and exome sequencing approach. We identified a likely molecular diagnosis in 70.5% families (31/44). The detection rate was significantly higher among probands with a family history of corneal dystrophy (15/16, 93.8%) than those without (16/28, 57.1%, p = .015), and among those who had undergone corneal graft surgery (9/9, 100.0%) compared to those who had not (22/35, 62.9%, p = .041). We identified eight novel variants in five genes and identified five families with syndromes associated with corneal dystrophies. Our findings highlight the genetic heterogeneity of corneal dystrophies and the clinical utility of genetic testing in reaching an accurate clinical diagnosis.

Quality of life in children with glaucoma: a qualitative interview study in Australia.

OBJECTIVE: Childhood glaucoma is a chronic vision-threatening condition that may significantly impact an individual's psychosocial well-being. There is a paucity of literature investigating the quality of life (QoL) in children with glaucoma. The aim of this study was to investigate and report on the QoL issues encountered by children with glaucoma. DESIGN: This is a qualitative interview study. Data were collected through semistructured interviews. NVivo V.12 software (QSR International Pty Ltd, Melbourne, Australia) was used to analyse and code data to identify QoL themes. The prominence of QoL themes was determined by the number of children who raised issues connected to the corresponding theme. SETTING: Interviews were conducted via telephone or videoconferencing between April 2020 and July 2021. PARTICIPANTS: Eighteen children with glaucoma, aged 8-17 years, who resided in Australia, were recruited from the Australian and New Zealand Registry of Advanced Glaucoma. RESULTS: Median child age was 12.1 years (IQR: 9.7-14.5 years) and 33% were female. Seven QoL themes were identified: 'coping', 'inconveniences' and 'emotional well-being' were more prominent themes than 'symptoms', 'ocular health concerns', 'social well-being' and 'autonomy'. Adaptive coping strategies included resilience throughout clinical examinations and establishing positive relationships with ophthalmologists. These minimised inconveniences related to clinic waiting times and pupillary dilatation. External to the clinical setting, children often dissociated from their glaucoma but struggled with glare symptoms and feeling misunderstood by fellow peers. Older children aged 13-17 years commonly disengaged from their glaucoma care and expressed an unwillingness to attend ophthalmic appointments. Older children further raised issues with career options, obtaining a driver's licence and family planning under the theme of autonomy. CONCLUSIONS: The psychosocial impact of childhood glaucoma extends beyond the clinical environment and was minimised using coping strategies. Older children may require additional social and ophthalmic support as they transition into adulthood.

Genetic testing in adult survivors of retinoblastoma in Denmark: A study of the experience and impact of genetic testing many years after initial diagnosis.

BACKGROUND: Survivors with heritable retinoblastoma (RB) face a high risk for second primary cancer and RB in their children. Knowledge of heredity can support second cancer surveillance, convey reproductive options or early diagnosis of RB in their offspring. Currently, all newly diagnosed Danish patients with RB are offered genetic testing, as opposed to a minority of survivors diagnosed before available DNA testing. OBJECTIVE: To examine RB survivors' response to unsolicited contact, uptake of genetic testing, and RB1 variant detection rate, and to qualitatively evaluate the experience and overall impact of genetic testing for heritable RB. METHODS: Genetically untested adult RB survivors were invited to receive genetic counseling, undergo genetic testing for heritable RB and complete an eye examination. The number of responses, uptake of genetic testing and genetic results are descriptively reported. Additionally, responding survivors participated in a qualitative interview study of the perceived impact of genetic testing. Interviews were audio-recorded, transcribed verbatim and thematically analyzed. RESULTS: Among invited RB survivors, 58% responded. Of these, 88% opted for genetic counseling and genetic testing. A diagnosis of heritable RB was established in 23% of RB survivors. Interestingly, all of these survivors were unilaterally affected. Analysis of data from the interviews revealed three recurring themes regarding the impact of genetic counseling and testing several years after initial diagnosis: 'Risk of what?', 'Knowledge is important' and 'Impact of the result'. The possible risk ofsecond cancer and RB in their children was new knowledge for several participants; however, in general, the participants appreciated receiving genetic information and certainty about heredity. Accordingly, the impact of genetic counseling and testing was perceived in a positive way. CONCLUSION: Overall, RB survivors valued the opportunity to receive genetic counseling and undergo genetic testing many years after diagnosis. Responding RB survivors appreciated the invitation to test, felt well-informed and described little decisional conflict regarding their decision-making, valuing the genetic information and certainty. Heritable RB was confirmed in 23% of the previously untested RB survivors. These individuals emphasized the value of knowing and being proactive regarding both reproduction and cancer risk.

The Caregiver Experience in Childhood Glaucoma: An Interview Study.

PURPOSE: To investigate and report on the quality-of-life (QoL) issues experienced by caregivers of individuals with childhood glaucoma. DESIGN: Exploratory, qualitative study. PARTICIPANTS: Thirty-five caregivers of individuals with childhood glaucoma (defined as disease onset before 18 years of age) recruited from the Australian and New Zealand Registry of Advanced Glaucoma. METHODS: A qualitative research methodology (interpretive phenomenology) was applied. Data were collected through semistructured in-depth interviews. NVivo-12 software (QSR International Pty Ltd) was used to analyze, code, and organize data into QoL themes inductively. MAIN OUTCOME MEASURES: Quality-of-life themes and their subthemes. RESULTS: The mean caregiver age was 50.2 ± 13.6 years, and 27 of 35 caregivers (77%) were mothers of an individual with childhood glaucoma. A total of 6 QoL themes were identified. Coping strategies and emotional well-being were the most prominent themes. Caregivers frequently adopted problem-focused adaptive coping strategies including partner or peer support, and normalization. A caregiver's psychosocial well-being was often impacted by feelings of guilt and regret regarding their child's delayed diagnosis, fear and anxiety related to medical and social support, and loss of control as their child developed medical autonomy. The effect of family planning from the perspective of the caregiver formed a novel QoL theme and was associated with normalization and parental confidence in management of the condition. CONCLUSIONS: Childhood glaucoma poses a substantial threat to a caregiver's psychosocial well-being. Strategies that promote normalization, peer support, psychotherapeutic intervention, and genetic counseling may be indicated and, indeed, critical to the caregiver as they adapt to supporting their child with glaucoma.

Sex, gender, and retinoblastoma: analysis of 4351 patients from 153 countries.

OBJECTIVE: To investigate in a large global sample of patients with retinoblastoma whether sex predilection exists for this childhood eye cancer. METHODS: A cross-sectional analysis including 4351 treatment-naive retinoblastoma patients from 153 countries who presented to 278 treatment centers across the world in 2017. The sex ratio (male/female) in the sample was compared to the sex ratio at birth by means of a two-sided proportions test at global level, country economic grouping, continent, and for selected countries. RESULTS: For the entire sample, the mean retinoblastoma sex ratio, 1.20, was higher than the weighted global sex ratio at birth, 1.07 (p < 0.001). Analysis at economic grouping, continent, and country-level demonstrated differences in the sex ratio in the sample compared to the ratio at birth in lower-middle-income countries (n = 1940), 1.23 vs. 1.07 (p = 0.019); Asia (n = 2276), 1.28 vs. 1.06 (p < 0.001); and India (n = 558), 1.52 vs. 1.11 (p = 0.008). Sensitivity analysis, excluding data from India, showed that differences remained significant for the remaining sample (χ2 = 6.925, corrected p = 0.025) and for Asia (χ2 = 5.084, corrected p = 0.036). Excluding data from Asia, differences for the remaining sample were nonsignificant (χ2 = 2.205, p = 0.14). CONCLUSIONS: No proof of sex predilection in retinoblastoma was found in the present study, which is estimated to include over half of new retinoblastoma patients worldwide in 2017. A high male to female ratio in Asian countries, India in specific, which may have had an impact on global-level analysis, is likely due to gender discrimination in access to care in these countries, rather than a biological difference between sexes.

Quality of Life in Adults with Childhood Glaucoma: An Interview Study.

PURPOSE: To explore and report on the quality-of-life (QoL) issues encountered by adults with childhood glaucoma. DESIGN: Exploratory qualitative study. PARTICIPANTS: Forty-seven participants with childhood glaucoma (defined as disease onset <18 years) recruited from the Australian and New Zealand Registry of Advanced Glaucoma (ANZRAG). METHODS: A qualitative research methodology (interpretive phenomenology) was applied, and data were collected through semistructured in-depth interviews. NVivo-12 software (QSR International Pty Ltd) was used to inductively analyze and code data to identify QoL themes pertinent to the cohort studied. MAIN OUTCOME MEASURES: Quality-of-life themes and subthemes. RESULTS: Mean participant age was 40.0 ± 15.3 years, and 55% of participants were female. We identified 10 QoL themes pertinent to adults living with childhood glaucoma. Coping strategies and emotional well-being were the most prominent themes. Maladaptive coping strategies, including treatment nonadherence, were observed more commonly in individuals aged <40 years and those without a vision impairment or reviewed less regularly. Emotional well-being was affected by feelings of being misunderstood because of the rarity of the condition, being self-conscious of physical manifestations of the disease, and anxiety related to possible disease progression and vision loss. The effect of childhood glaucoma on family planning formed a novel QoL theme and included worry for their child to inherit the condition and an inability to fulfill parental duties. This often led to genetic counseling-seeking behaviors. Mobility issues were infrequently experienced. CONCLUSIONS: Childhood glaucoma poses a substantial impact to the emotional well-being of adults with the condition, which is mediated by the use of coping strategies. Genetic counseling and family planning options may be important. This study supports the development of a childhood glaucoma-specific patient-reported outcome measure for assessment of the psychosocial impact of childhood glaucoma in adults.

Establishing risk of vision loss in Leber hereditary optic neuropathy.

We conducted an updated epidemiological study of Leber hereditary optic neuropathy (LHON) in Australia by using registry data to establish the risk of vision loss among different LHON mutations, sex, age at onset, and mitochondrial haplogroup. We identified 96 genetically unrelated LHON pedigrees, including 56 unpublished pedigrees, and updated 40 previously known pedigrees, comprising 620 affected individuals and 4,948 asymptomatic carriers. The minimum prevalence of vision loss due to LHON in Australia in 2020 was one in 68,403 individuals. Although our data confirm some well-established features of LHON, the overall risk of vision loss among those with a LHON mutation was lower than reported previously-17.5% for males and 5.4% for females. Our findings confirm that women, older adults, and younger children are also at risk. Furthermore, we observed a higher incidence of vision loss in children of affected mothers as well as in children of unaffected women with at least one affected brother. Finally, we confirmed our previous report showing a generational fall in prevalence of vision loss among Australian men. Higher reported rates of vision loss in males with a LHON mutation are not supported by our work and other epidemiologic studies. Accurate knowledge of risk is essential for genetic counseling of individuals with LHON mutations. This knowledge could also inform the detection and validation of potential biomarkers and has implications for clinical trials of treatments aimed at preventing vision loss in LHON because an overestimated risk may lead to an underpowered study or a false claim of efficacy.

Living with heritable retinoblastoma and the perceived role of regular follow-up at a retinoblastoma survivorship clinic: 'That is exactly what I have been missing'.

OBJECTIVE: To explore living with heritable retinoblastoma, specifically survivors' perceived role of regular follow-up at a retinoblastoma survivorship clinic. METHODS AND ANALYSIS: Adult survivors of heritable retinoblastoma were recruited from the Retinoblastoma Survivorship Clinic, Aarhus University Hospital. Ten survivors participated in individual explorative, semistructured interviews. Thematic data analysis was conducted. RESULTS: Five key themes relating to vision, social life, family, second cancer risk and the healthcare system were identified. Subthemes relating to the Retinoblastoma Survivorship Clinic included the retinoblastoma coordinator, cancer risk, psychosocial support and genetic knowledge. The retinoblastoma-related physical and psychosocial issues influenced survivors' everyday living; however, the opportunity to live a normal life varied considerably, with the majority experiencing no major limitations. The need for specialised management and a coordinator was emphasised to be the main value of the Retinoblastoma Survivorship Clinic. CONCLUSION: Despite reporting an overall normal life and no major limitations in daily living activities, our data confirm that heritable retinoblastoma impacts several aspects of daily living. Uniquely, this study demonstrates that the main value of the Retinoblastoma Survivorship Clinic was a specialised contact person and coordinator in the healthcare system, providing continuous and necessary management and guidance after retinoblastoma treatment, and for all aspects of health related to heritable retinoblastoma. The needs of heritable retinoblastoma survivors are complex and extensive, and the specific role of the healthcare system to support survivorship should be prioritised, specialised and multidisciplinary.

Childhood and Early Onset Glaucoma Classification and Genetic Profile in a Large Australasian Disease Registry.

PURPOSE: To report the relative frequencies of childhood and early onset glaucoma subtypes and their genetic findings in a large single cohort. DESIGN: Retrospective clinical and molecular study. PARTICIPANTS: All individuals with childhood glaucoma (diagnosed 0 to <18 years) and early onset glaucoma (diagnosed 18 to <40 years) referred to a national disease registry. METHODS: We retrospectively reviewed the referrals of all individuals with glaucoma diagnosed at <40 years of age recruited to the Australian and New Zealand Registry of Advanced Glaucoma (ANZRAG). Subtypes of glaucoma were determined using the Childhood Glaucoma Research Network (CGRN) classification system. DNA extracted from blood or saliva samples underwent sequencing of genes associated with glaucoma. MAIN OUTCOME MEASURES: The phenotype and genotype distribution of glaucoma diagnosed at <40 years of age. RESULTS: A total of 290 individuals (533 eyes) with childhood glaucoma and 370 individuals (686 eyes) with early onset glaucoma were referred to the ANZRAG. Primary glaucoma was the most prevalent condition in both cohorts. In the childhood cohort, 57.6% of individuals (167/290, 303 eyes) had primary congenital glaucoma (PCG), and 19.3% (56/290, 109 eyes) had juvenile open-angle glaucoma. Juvenile open-angle glaucoma constituted 73.2% of the early onset glaucoma cohort (271/370, 513 eyes). Genetic testing in probands resulted in a diagnostic yield of 24.7% (125/506) and a reclassification of glaucoma subtype in 10.4% of probands (13/125). The highest molecular diagnostic rate was achieved in probands with glaucoma associated with nonacquired ocular anomalies (56.5%). Biallelic variants in CYP1B1 (n = 29, 23.2%) and heterozygous variants in MYOC (n = 24, 19.2%) and FOXC1 (n = 21, 16.8%) were most commonly reported among probands with a molecular diagnosis. Biallelic CYP1B1 variants were reported in twice as many female individuals as male individuals with PCG (66.7% vs. 33.3%, P = 0.02). CONCLUSIONS: We report on the largest cohort of individuals with childhood and early onset glaucoma from Australasia using the CGRN classification. Primary glaucoma was most prevalent. Genetic diagnoses ascertained in 24.7% of probands supported clinical diagnoses and genetic counseling. International collaborative efforts are required to identify further genes because the majority of individuals still lack a clear molecular diagnosis.

Parent satisfaction and acceptability of telehealth consultations in pediatric ophthalmology: initial experience during the COVID-19 pandemic.

Telehealth in pediatric ophthalmology has predominantly been utilized and reported in the setting of clinician-to-clinician opinion or store-and-forward of images, particularly in the diagnosis and management of retinopathy of prematurity (ROP). We present our initial experience of using a telehealth model of care to deliver real-time specialist pediatric ophthalmology services during the COVID-19 pandemic. Over a 5-week period, parents were invited to complete an anonymous survey following a telehealth ophthalmology consultation for their child. The survey explored their satisfaction, acceptance, and feedback relating to their experience. With an overall response rate of 49.4%, satisfaction was high (43.8% very satisfied; 38.2% satisfied). Most parents (71.9%) would consider telehealth for future ophthalmology consultations for their child.

Improving parents' knowledge of early signs of paediatric eye disease: A double-blind randomized controlled trial.

IMPORTANCE: Educating parents to recognize signs of eye disease and consult a healthcare professional is critical to timely diagnosis, intervention and outcomes. BACKGROUND: We evaluate the effectiveness of an eye-health information pamphlet on parents' level of concern and help-seeking intention should they hypothetically observe leukocoria or strabismus in their child. DESIGN: Double-blind, randomized controlled trial conducted at a metropolitan antenatal outpatient clinic. PARTICIPANTS: In total, 518 pregnant women were enrolled in the study. METHODS: After completing a study-specific, pre-test survey describing hypothetical clinical scenarios at baseline, participants were randomly assigned to receive a pamphlet on either paediatric eye health (intervention) or infant play (control). The post-test survey was sent by email 2 weeks after baseline. MAIN OUTCOME MEASURES: A change in the parents' level of concern if they observed leukocoria or strabismus and a change in their help-seeking intention if they hypothetically observed leukocoria or strabismus in their child. RESULTS: Of the 518 women, 382 (73.7%) completed the post-test survey. At follow-up, women who received the intervention were more likely to report a higher level of concern if they observed leukocoria (OR 1.711 [CI: 1.176-2.497] P = .005]) and were less likely to delay help-seeking (OR 0.560 [CI 0.382-0.817] P = .003). No change in the level of concern for strabismus was identified between the groups; however, at follow-up, women who received the intervention were less likely to delay help-seeking (OR 0.318 [CI 0.125-0.806] P = .016). CONCLUSION AND RELEVANCE: Providing parents with relevant, evidence-based information can significantly improve their knowledge and positively influence help-seeking intentions if leukocoria or strabismus are observed.

Biallelic CPAMD8 Variants Are a Frequent Cause of Childhood and Juvenile Open-Angle Glaucoma.

PURPOSE: Developmental abnormalities of the ocular anterior segment in some cases can lead to ocular hypertension and glaucoma. CPAMD8 is a gene of unknown function recently associated with ocular anterior segment dysgenesis, myopia, and ectopia lentis. We sought to assess the contribution of biallelic CPAMD8 variants to childhood and juvenile open-angle glaucoma. DESIGN: Retrospective, multicenter case series. PARTICIPANTS: A total of 268 probands and their relatives with a diagnosis of childhood or juvenile open-angle glaucoma. PURPOSE: Developmental abnormalities of the ocular anterior segment in some cases can lead to ocular hypertension and glaucoma. CPAMD8 is a gene of unknown function recently associated with ocular anterior segment dysgenesis, myopia, and ectopia lentis. We sought to assess the contribution of biallelic CPAMD8 variants to childhood and juvenile open-angle glaucoma. METHODS: Patients underwent a comprehensive ophthalmic assessment, with DNA from patients and their relatives subjected to genome, exome, or capillary sequencing. CPAMD8 RNA expression analysis was performed on tissues dissected from cadaveric human eyes. MAIN OUTCOME MEASURES: Diagnostic yield within a cohort of childhood and juvenile open-angle glaucoma, prevalence and risk of ophthalmic phenotypes, and relative expression of CPAMD8 in the human eye. RESULTS: We identified rare (allele frequency < 4×10-5) biallelic CPAMD8 variants in 5.7% (5/88) of probands with childhood glaucoma and 2.1% (2/96) of probands with juvenile open-angle glaucoma. When including family members, we identified 11 individuals with biallelic variants in CPAMD8 from 7 unrelated families. Nine of these individuals were diagnosed with glaucoma (9/11, 81.8%), with a mean age at diagnosis of 9.22±14.89 years, and all individuals with glaucoma required 1 or more incisional procedures to control high intraocular pressure. Iris abnormalities were observed in 9 of 11 individuals, cataract was observed in 8 of 11 individuals (72.7%), and retinal detachment was observed in 3 of 11 individuals (27.3%). CPAMD8 expression was highest in neural crest-derived tissues of the adult anterior segment, suggesting that CPAMD8 variation may cause malformation or obstruction of key drainage structures. CONCLUSIONS: Biallelic CPAMD8 variation was associated with a highly heterogeneous phenotype and in our cohorts was the second most common inherited cause of childhood glaucoma after CYP1B1 and juvenile open-angle glaucoma after MYOC. CPAMD8 sequencing should be considered in the investigation of both childhood and juvenile open-angle glaucoma, particularly when associated with iris abnormalities, cataract, or retinal detachment.

The genetic and clinical landscape of nanophthalmos and posterior microphthalmos in an Australian cohort.

Nanophthalmos and posterior microphthalmos are ocular abnormalities in which both eyes are abnormally small, and typically associated with extreme hyperopia. We recruited 40 individuals from 13 kindreds with nanophthalmos or posterior microphthalmos, with 12 probands subjected to exome sequencing. Nine probands (69.2%) were assigned a genetic diagnosis, with variants in MYRF, TMEM98, MFRP, and PRSS56. Two of four PRSS56 families harbored the previously described c.1066dupC variant implicated in over half of all reported PRSS56 kindreds, with different surrounding haplotypes in each family suggesting a mutational hotspot. Individuals with a genetic diagnosis had shorter mean axial lengths and higher hyperopia than those without, with recessive forms associated with the most extreme phenotypes. These findings detail the genetic architecture of nanophthalmos and posterior microphthalmos in a cohort of predominantly European ancestry, their relative clinical phenotypes, and highlight the shared genetic architecture of rare and common disorders of refractive error.

Prevalence of FOXC1 Variants in Individuals With a Suspected Diagnosis of Primary Congenital Glaucoma.

Importance: Both primary and secondary forms of childhood glaucoma have many distinct causative mechanisms, and in many cases a cause is not immediately clear. The broad phenotypic spectrum of secondary glaucoma, particularly in individuals with variants in FOXC1 or PITX2 genes associated with Axenfeld-Rieger syndrome, makes it more difficult to diagnose patients with milder phenotypes. These cases are occasionally classified and managed as primary congenital glaucoma. Objective: To investigate the prevalence of FOXC1 variants in participants with a suspected diagnosis of primary congenital glaucoma. Design, Setting, and Participants: Australian and Italian cohorts were recruited from January 1, 2007, through March 1, 2016. Australian individuals were recruited through the Australian and New Zealand Registry of Advanced Glaucoma and Italian individuals through the Genetic and Ophthalmology Unit of l'Azienda Socio-Sanitaria Territoriale Grande Ospedale Metropolitano Niguarda in Milan, Italy. We performed exome sequencing, in combination with Sanger sequencing and multiplex ligation-dependent probe amplification, to detect variants of FOXC1 in individuals with a suspected diagnosis of primary congenital glaucoma established by their treating specialist. Data analysis was completed from June 2015 to November 2017. Main Outcome and Measures: Identification of single-nucleotide and copy number variants in FOXC1, along with phenotypic characterization of the individuals who carried them. Results: A total of 131 individuals with a suspected diagnosis of primary congenital glaucoma were included. The mean (SD) age at recruitment in the Australian cohort was 24.3 (18.1) years; 37 of 84 Australian participants (44.0%) were female, and 71 of 84 (84.5%) were of European ancestry. The mean (SD) age at recruitment was 22.5 (18.4) years in the Italian cohort; 21 of 47 Italian participants (44.7%) were female, and 45 of 47 (95.7%) were of European ancestry. We observed rare, predicted deleterious FOXC1 variants in 8 of 131 participants (6.1%), or 8 of 166 participants (4.8%) when including those explained by variants in CYP1B1. On reexamination or reinvestigation, all of these individuals had at least 1 detectable ocular and/or systemic feature associated with Axenfeld-Rieger syndrome. Conclusions and Relevance: These data highlight the genetic and phenotypic heterogeneity of childhood glaucoma and support the use of gene panels incorporating FOXC1 as a diagnostic aid, especially because clinical features of Axenfeld-Rieger syndrome can be subtle. Further replication of these results will be needed to support the future use of such panels.