Intraretinal hemorrhages and detailed retinal phenotype of three patients with Alagille syndrome.

PURPOSE: To explore patterns of disease expression in Alagille syndrome (ALGS). METHODS: Patients underwent ophthalmic examination, optical coherence tomography (OCT) imaging, fundus intravenous fluorescein angiography (IVFA), perimetry and full-field electroretinograms (ffERGs). An adult ALGS patient had multimodal imaging and specialized perimetry. RESULTS: The proband (P1) had a heterozygous pathogenic variant in JAG1; (p.Gln410Ter) and was incidentally diagnosed at age 7 with a superficial retinal hemorrhage, vascular tortuosity, and midperipheral pigmentary changes. The hemorrhage recurred 15 months later. Her monozygotic twin sister (P2) had a retinal hemorrhage at the same location at age 11. Visual acuities for both patients were 20/30 in each eye. IVFA was normal. OCT showed thinning of the outer nuclear in the peripapillary retina. A ffERG showed normal cone-mediated responses in P1 (rod-mediated ERGs not documented), normal ffERGs in P2. Coagulation and liver function were normal. An unrelated 42-year-old woman with a de-novo pathogenic variant (p. Gly386Arg) in JAG1 showed a similar pigmentary retinopathy and hepatic vascular anomalies; rod and cone function was normal across large expanses of structurally normal retina that sharply transitioned to a blind atrophic peripheral retina. CONCLUSION: Nearly identical recurrent intraretinal hemorrhages in monozygotic twins with ALGS suggest a shared subclinical microvascular abnormality. We hypothesize that the presence of large areas of functionally and structurally intact retina surrounded by severe chorioretinal degeneration, is against a predominant involvement of JAG1 in the function of the neurosensory retina, and that instead, primary abnormalities of chorioretinal vascular development and/or homeostasis may drive the peculiar phenotypes.

Large-scale death of retinal astrocytes during normal development is non-apoptotic and implemented by microglia.

Naturally occurring cell death is a fundamental developmental mechanism for regulating cell numbers and sculpting developing organs. This is particularly true in the nervous system, where large numbers of neurons and oligodendrocytes are eliminated via apoptosis during normal development. Given the profound impact of death upon these two major cell populations, it is surprising that developmental death of another major cell type-the astrocyte-has rarely been studied. It is presently unclear whether astrocytes are subject to significant developmental death, and if so, how it occurs. Here, we address these questions using mouse retinal astrocytes as our model system. We show that the total number of retinal astrocytes declines by over 3-fold during a death period spanning postnatal days 5-14. Surprisingly, these astrocytes do not die by apoptosis, the canonical mechanism underlying the vast majority of developmental cell death. Instead, we find that microglia engulf astrocytes during the death period to promote their developmental removal. Genetic ablation of microglia inhibits astrocyte death, leading to a larger astrocyte population size at the end of the death period. However, astrocyte death is not completely blocked in the absence of microglia, apparently due to the ability of astrocytes to engulf each other. Nevertheless, mice lacking microglia showed significant anatomical changes to the retinal astrocyte network, with functional consequences for the astrocyte-associated vasculature leading to retinal hemorrhage. These results establish a novel modality for naturally occurring cell death and demonstrate its importance for the formation and integrity of the retinal gliovascular network.

A novel missense mutation in BEST1 associated with an autosomal-dominant vitreoretinochoroidopathy (ADVIRC) phenotype.

BACKGROUND: To report a 68-year-old female with an autosomal-dominant vitreoretinochoroidopathy (ADVIRC) phenotype associated with a subretinal hemorrhage (SRH) and novel BEST1 pathogenic variation p.Met571Thr. MATERIALS AND METHODS: The patient was assessed by fundus photography, fluorescence and indocyanine green angiography, spectral-domain optical coherence tomography, photopic and scotopic electroretinogram (ERG), and electrooculogram (EOG). Whole-exome and Sanger sequencing of the patient's and selected family members' DNA was performed. Ophthalmoscopic examinations were also performed on six patient's relatives. RESULTS: The patient presented moderate vitreous and SRH in the left eye. A distinct, annular hyperpigmented band was present in both eyes. Vitrectomy improved visual acuity, and the SRH gradually regressed without recurrence. Preserved macular function was shown by optical coherence tomography (OCT). Genetic analysis identified a novel heterozygous mutation, resulting in p.Met571Thr in BEST1. No mutations were observed in a panel of other eye disease genes, suggesting that this pathogenic variation in BEST1 is associated with an ADVIRC phenotype. No other evaluated family member had the variant or the fundus findings. CONCLUSIONS: We present a patient with a novel p.Met571Thr pathogenic variation associated with an ADVIRC phenotype. SRH is a unique finding in ADVIRC patients and may correspond to peripheral exudative hemorrhagic chorioretinopathy. The BEST1 pathogenic variation p.Met571Thr might be the likely cause of ADVIRC in this patient. However, further study is necessary to determine whether this mutation is causative.

A Deep Phenotype Association Study Reveals Specific Phenotype Associations with Genetic Variants in Age-related Macular Degeneration: Age-Related Eye Disease Study 2 (AREDS2) Report No. 14.

PURPOSE: Age-related macular degeneration (AMD), a multifactorial disease with variable phenotypic presentation, was associated with 52 single nucleotide polymorphisms (SNPs) at 34 loci in a genome-wide association study (GWAS). These genetic variants could modulate different biological pathways involved in AMD, contributing to phenotypic variability. To better understand the effects of these SNPs, we performed a deep phenotype association study (DeePAS) in the Age-Related Eye Disease Study 2 (AREDS2), followed by replication using AREDS participants, to identify genotype associations with AMD and non-AMD ocular and systemic phenotypes. DESIGN: Cohort study. PARTICIPANTS: AREDS and AREDS2 participants. METHODS: AREDS2 participants (discovery cohort) had detailed phenotyping for AMD; other eye conditions; cardiovascular, neurologic, gastrointestinal, and endocrine disease; cognitive function; serum nutrient levels; and others (total of 139 AMD and non-AMD phenotypes). Genotypes of the 52 GWAS SNPs were obtained. The DeePAS was performed by correlating the 52 SNPs to all phenotypes using logistic and linear regression models. Associations that reached Bonferroni-corrected statistical significance were replicated in AREDS. MAIN OUTCOME MEASURES: Genotype-phenotype associations. RESULTS: A total of 1776 AREDS2 participants had 5 years follow-up; 1435 AREDS participants had 10 years. The DeePAS revealed a significant association of the rs3750846 SNP at the ARMS2/HTRA1 locus with subretinal/sub-retinal pigment epithelial (RPE) hemorrhage related to neovascular AMD (odds ratio 1.55 [95% confidence interval 1.31-1.84], P = 2.67 × 10-7). This novel association remained significant after conditioning on participants with neovascular AMD (P = 2.42 × 10-4). Carriers of rs3750846 had poorer visual acuity during follow-up (P = 6.82 × 10-7) and were more likely to have a first-degree relative with AMD (P = 5.38 × 10-6). Two SNPs at the CFH locus, rs10922109 and rs570618, were associated with the drusen area in the Early Treatment Diabetic Retinopathy Study Report (ETDRS) grid (P = 2.29 × 10-11 and P = 3.20 × 10-9, respectively) and the center subfield (P = 1.24 × 10-9 and P = 6.68 × 10-8, respectively). SNP rs570618 was additionally associated with the presence of calcified drusen (P = 5.38 × 10-6). Except for positive family history of AMD with rs3750846, all genotype-phenotype associations were significantly replicated in AREDS. No pleiotropic associations were identified. CONCLUSIONS: The association of the SNP at the ARMS2/HTRA1 locus with subretinal/sub-RPE hemorrhage and poorer visual acuity and of SNPs at the CFH locus with drusen area may provide new insights in pathophysiological pathways underlying different stages of AMD.

The Relation Between Endothelial Nitric Oxide Synthase Polymorphisms and Normal Tension Glaucoma.

PURPOSE: We investigated whether polymorphisms of the endothelial NO synthase (eNOS) gene are associated with normal tension glaucoma (NTG). We also investigated whether the eNOS polymorphisms are associated with NTG subgroups [NTG with and without optic disc hemorrhage (DH)]. METHODS: A total of 251 patients with NTG and 245 healthy volunteers were enrolled in this study. DNA from peripheral blood leukocytes was extracted, and the genotypes of 4 polymorphisms (rs2070744, rs1549758, rs1799983, and rs2566514) in the eNOS gene were determined using restriction fragment length polymorphism and the SNaPshot method. The primary outcome was to investigate the relation between eNOS polymorphisms and NTG. The secondary outcome was to compare the frequencies of the polymorphic genotypes among the NTG subgroups. Bonferroni correction was used to adjust for type I error. RESULTS: In all subjects, the genotype distribution was in accordance with Hardy-Weinberg equilibrium. None of the 4 polymorphisms showed any significant difference in the frequencies of alleles or genotypes between the NTG patients and controls. In the further analysis comparing the genotypic frequencies between NTG with DH and normal controls, the CC/CT genotype of rs2070744 was significantly associated with DH in NTG patients (genotypic association test, P-value=0.0041). On the multiple logistic regression analysis adjusted for covariates such as sex and age, the NTG with DH was associated with polymorphic genotypes of rs2070744 with a borderline significance (additive genetic model, P=0.0070). CONCLUSIONS: Our results indicates that eNOS rs2070744 can be associated with NTG patients with DH. This finding suggests that the eNOS polymorphism may be a genetic risk factor in the development of DH in NTG patients.

Bilateral persistent fetal vasculature due to a mutation in the Norrie disease protein gene.

We report a case of a 7-week-old boy with bilateral leukocoria and asymmetric microphthalmia who was found to have Norrie disease. Symmetrically hyperdense globes with no evidence of calcification were seen on CT scan. The MRI showed bilateral retinal hemorrhages resulting in conical vitreous chambers-narrow at the optic disc and widened toward the lens-characteristic of persistent fetal vasculature. Genetic evaluation revealed a previously undescribed mutation in the Norrie disease protein gene.

Two families with novel missense mutations in COL4A1: When diagnosis can be missed.

Mutations in COL4A1, encoding one of the six collagen type IV proteins, cover a wide spectrum of autosomal dominant overlapping phenotypes including porencephaly, small-vessel disease and hemorrhagic stroke, leukoencephalopathy, hereditary angiopathy with nephropathy, aneurysms and muscle cramp (HANAC) syndrome, and Walker-Warburg syndrome. Over 50 mutations are known, mainly being missense changes. Intra- and inter-familial variability has been reported. We studied two Italian families in which the proband had a clinical diagnosis of COL4A1-related disorder. We found two novel mutations (c.1249G>C; p.Gly417Arg and c.2662G>C; p.Gly888Arg). Both involved highly conserved amino acids and were predicted as being deleterious by bioinformatics tools. The c.1249G>C (p.Gly417Arg) segregated in four subjects with variable neurological phenotypes, namely leukoencephalopathy with muscle symptoms, brain small-vessel disease, and mild infantile encephalopathy. A fourth case was a carrier of the mutation without any neurological symptoms and an MRI with a specific white matter anomaly. The c.2662G>C (p.Gly888Arg) mutation was de novo in the proband. After a temporary motor impairment at age 14, the subject complained of mild imbalance at age 30, during the third trimester of her twin pregnancy, when an anomaly of the left brain hemisphere was documented in one fetus. Both her male dizygotic twins presented a severe motor delay, early convulsions, and leukoencephalopathy, and were carriers of the mutation. In summary, we confirm that high intra-familial variability of COL4A1 mutations with very mild phenotypes, the apparent incomplete penetrance, and de novo changes may become a "dilemma" for clinicians and genetic counselors.

Next generation sequencing uncovers a missense mutation in COL4A1 as the cause of familial retinal arteriolar tortuosity.

OBJECTIVES: Our aim was to determine the molecular cause of autosomal dominant familial retinal arteriolar tortuosity (FRAT) in a family with three affected subjects. MATERIAL AND METHODS: Ophthalmologic evaluation included determination of best-corrected visual acuity (BCVA), slit-lamp and dilated fundus inspection, applanation tonometry, fundus photography, and fluorescein retinal angiography (FA). Molecular methods included whole exome sequencing analysis and Sanger sequencing validation of putative causal mutation in DNA from affected individuals. RESULTS: Typical signs of familial retinal arteriolar tortuosity were observed in all three patients. Exome sequencing identified a heterozygous c.1528G > A (p. Gly510Arg) mutation in COL4A1. Sanger sequencing confirmed that all three patients harbored the same pathogenetic mutation in COL4A1. The p. Gly510Arg variant in COL4A1 was absent in DNA from an available unaffected daughter, from a set of control alleles, and from publicly available databases. CONCLUSIONS: The molecular basis of familial retinal arteriolar tortuosity was identified for the first time, thus expanding the human phenotypes linked to COL4A1 mutations. Interestingly, the COL4A1 p.Gly510Arg mutation has been previously identified in a family with HANAC (Hereditary Angiopathy with Nephropathy, Aneurysm and Cramps), a multisystemic disease featuring retinal arteriolar tortuosity. No cerebral, neurologic, renal, cardiac or vascular anomalies were recognized in the pedigree described here. These data indicate that identical mutations in COL4A1 can originate both eye-restricted and systemic phenotypes.

Preliminary study of retinal pathological features in preterm birth pups exposed to an animal model of oxygen-induced retinopathy in mice.

BACKGROUND: The main risk factors of retinopathy of prematurity (ROP) are low gestational age and low birth weight, which are mainly caused by preterm birth. Currently, the animal model of oxygen-induced retinopathy (OIR) in mice is the most widely used model in ROP-associated studies. However, the experimental mice are normal-term pups, and may not mimic the pathogenic status of human ROP patients. In this study, we investigated the retinal pathological features in preterm birth pups exposed to an animal model of oxygen-induced retinopathy in mice. METHODS: Preterm-birth mice were obtained from pregnant C57BL/6J mice that were induced by an intraperitoneal injection of lipopolysaccharide (LPS). The preterm and control mice were treated with high oxygen (75%) from postnatal day 7 (P7) to P12. The mice were perfused with high-molecular-weight FITC-dextran on P12, P15 and P17, and the retinas were whole-mounted and imaged. Vascular endothelial growth factor (VEGF) mRNA was also detected. Cross-sections of the retina were stained with hematoxylin and eosin (H&E) to identify preretinal neovascular tufts. For general observation, whole retinal images were also obtained using a microscope. RESULTS: Leakage of the retinal blood vessels was aggravated in the preterm mice, particularly on P12 and P15. The non-perfused areas of the retina (pixel value, 183,673 ± 28,148 vs 132,110 ± 23,732, P = 0.009) and the number of preretinal endothelial cell nuclei were smaller (30.17 ± 8.33 vs 22.17 ± 6.74, P < 0.0001) on P17. The VEGF mRNA levels in the retinas were higher on P12 and P15 but lower on P17, compared with the control mice. Retinal hemorrhage was observed in the preterm mouse group (five out of six examined eyes). CONCLUSIONS: Preterm-birth mice that were subject to OIR exhibited several pathological features, such as retinal hemorrhage, severe retinal leakage and moderate retinal neovascularization, which were similar to the clinical manifestations in ROP patients.

Transthyretin Ala36Pro mutation in a Chinese pedigree of familial transthyretin amyloidosis with elevated vitreous and serum vascular endothelial growth factor.

The familial transthyretin (TTR) amyloidosis (FTA) demonstrates variable penetrance of clinical features associated with mutations in the plasma thyroid hormone-binding protein TTR gene. The purpose of this study was to assess the ocular features, to analyze vitreous and serum vascular endothelial growth factor (VEGF) levels, and to identify the genetic defect in a Chinese family with TTR FTA. The pedigree of interest was a three-generation family with eleven members. The primary ocular signs were vitreous opacities, beginning from the third or fourth decade, accompanied by retinal vasculitis, hemorrhages, and widespread pinpoint deposits in the peripheral retina. Two patients underwent vitrectomy with marked improvement of visual acuity postoperatively. Vitreous and serum samples for VEGF were analyzed with an enzyme-linked immunosorbent assay (ELISA). Forty-eight healthy adult volunteers were enrolled as a control group for the analysis of serum VEGF. Eight subjects who underwent vitrectomy for a macular epiretinal membrane or macular hole were enrolled as control for the analysis of vitreous VEGF. Both serum and vitreous VEGF levels of patients were raised compared to that of controls. Venous blood was collected from family members and the genomic DNA was extracted. All exons and exon-intron boundaries of the TTR gene were sequenced. A previously-described pathogenic transversion in exon 2 (c.G106C, p.Ala36Pro) was identified. Within this family eight individuals were confirmed as affected. In conclusion, a Chinese family with TTR Ala36Pro associated FTA is characterized by early ocular involvement. Widespread pinpoint lesions indicate RPE lesions caused by TTR deposition. FTA is associated with increased VEGF levels, both in serum and vitreous.