First implication of MIP in bilateral microphthalmia with persistent fetal vasculature.

Persistent fetal vasculature (PFV) is a rare malformative ocular disorder resulting from the failure of the hyaloid vasculature to regress. The severity of the visual impairment is depending on the underlying eye defects, ranging from discreet hyaloid remnants to severe ocular anomalies. Although PFV is generally unilateral, sporadic and idiopathic, a genetic cause has been described in some individuals, especially those presenting with a bilateral and/or syndromic form of PFV. The genes occasionally described in PFV are most often responsible for a wide spectrum of ocular phenotypes such as ATOH7 or NDP, a gene also known to be involved in Norrie disease, a X-linked vitreoretinopathy with extra-ocular features. We describe here a patient with an ocular phenotype consisting in non-syndromic bilateral PFV with cataract and microphthalmia, in whom a recurrent heterozygous de novo MIP disease-causing variant was detected after using a dedicated 119-ocular genes panel approach. Defects in the MIP gene are classically associated with dominant non-syndromic congenital cataract without other ocular malformative features. Thus, this case highlights the value of exploring individuals with PFV, even those with non-syndromic forms. It also broadens the phenotypic spectrum of the MIP gene, adding new insights into the gene networks underlying PFV pathophysiology, that remains unclear.

Bilateral anterior segment dysgenesis and persistent fetal vasculature associated with terminal 10q26 deletion.

Deletion of the 26q position on chromosome 10 results in a syndrome with well-documented systemic phenotypes. There are few reports of ophthalmic manifestations in terminal 10q26 deletion. We report a 4-week-old boy with terminal 10q26 deletion who had extensive ophthalmic abnormalities, including bilateral anterior segment dysgenesis and bilateral persistent fetal vasculature, with microphthalmia, microcornea, iris corectopia, congenital cataracts, and posterior embryotoxon.

Neogenin-loss in neural crest cells results in persistent hyperplastic primary vitreous formation.

Neogenin is a transmembrane receptor critical for multiple cellular processes, including neurogenesis, astrogliogenesis, endochondral bone formation, and iron homeostasis. Here we present evidence that loss of neogenin contributes to pathogenesis of persistent hyperplastic primary vitreous (PHPV) formation, a genetic disorder accounting for ~ 5% of blindness in the USA. Selective loss of neogenin in neural crest cells (as observed in Wnt1-Cre; Neof/f mice), but not neural stem cells (as observed in GFAP-Cre and Nestin-Cre; Neof/f mice), resulted in a dysregulation of neural crest cell migration or delamination, exhibiting features of PHPV-like pathology (e.g. elevated retrolental mass), unclosed retinal fissure, and microphthalmia. These results demonstrate an unrecognized function of neogenin in preventing PHPV pathogenesis, implicating neogenin regulation of neural crest cell delamination/migration and retinal fissure formation as potential underlying mechanisms of PHPV.

Modulating EGFR-MTORC1-autophagy as a potential therapy for persistent fetal vasculature (PFV) disease.

Persistent fetal vasculature (PFV) is a human disease that results from failure of the fetal vasculature to regress normally. The regulatory mechanisms responsible for fetal vascular regression remain obscure, as does the underlying cause of regression failure. However, there are a few animal models that mimic the clinical manifestations of human PFV, which can be used to study different aspects of the disease. One such model is the Nuc1 rat model that arose from a spontaneous mutation in the Cryba1 (crystallin, beta 1) gene and exhibits complete failure of the hyaloid vasculature to regress. Our studies with the Nuc1 rat indicate that macroautophagy/autophagy, a process in eukaryotic cells for degrading dysfunctional components to ensure cellular homeostasis, is severely impaired in Nuc1 ocular astrocytes. Further, we show that CRYBA1 interacts with EGFR (epidermal growth factor receptor) and that loss of this interaction in Nuc1 astrocytes increases EGFR levels. Moreover, our data also show a reduction in EGFR degradation in Nuc1 astrocytes compared to control cells that leads to over-activation of the mechanistic target of rapamycin kinase complex 1 (MTORC1) pathway. The impaired EGFR-MTORC1-autophagy signaling in Nuc1 astrocytes triggers abnormal proliferation and migration. The abnormally migrating astrocytes ensheath the hyaloid artery, contributing to the pathogenesis of PFV in Nuc1, by adversely affecting the vascular remodeling processes essential to regression of the fetal vasculature. Herein, we demonstrate in vivo that gefitinib (EGFR inhibitor) can rescue the PFV phenotype in Nuc1 and may serve as a novel therapy for PFV disease by modulating the EGFR-MTORC1-autophagy pathway. ABBREVIATIONS: ACTB: actin, beta; CCND3: cyclin 3; CDK6: cyclin-dependent kinase 6; CHQ: chloroquine; COL4A1: collagen, type IV, alpha 1; CRYBA1: crystallin, beta A1; DAPI: 4'6-diamino-2-phenylindole; EGFR: epidermal growth factor receptor; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFAP: glial fibrillary growth factor; KDR: kinase insert domain protein receptor; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MKI67: antigen identified by monoclonal antibody Ki 67; MTORC1: mechanistic target of rapamycin kinase complex 1; PARP: poly (ADP-ribose) polymerase family; PCNA: proliferating cell nuclear antigen; PFV: persistent fetal vasculature; PHPV: persistent hyperplastic primary vitreous; RPE: retinal pigmented epithelium; RPS6: ribosomal protein S6; RPS6KB1: ribosomal protein S6 kinase, polypeptide 1; SQSTM1/p62: sequestome 1; TUBB: tubulin, beta; VCL: vinculin; VEGFA: vascular endothelial growth factor A; WT: wild type.

Unilateral persistent fetal vasculature coexisting with anterior segment dysgenesia. / Vasculatura fetal persistente unilateral asociada a disgenesia del segmento anterior.

CASE REPORT: A case is presented of a 4 week-old female neonate with Peters anomaly (PA) and unilateral persistent foetal vasculature (PFV) referred to our centre due to esotropia. At 12 weeks of age, a penetrating keratoplasty and vitrectomy were performed without major complications in the immediate post-operative period. The patient is currently under an intensive treatment for amblyopia and secondary glaucoma. DISCUSSION: Surgical treatment of PFV is controversial, with prevention of amblyopia, phthisis, and glaucoma being the main reasons for it. Patients with unilateral PFV and type II PA could be good candidates for this combined surgical procedure.

Simultaneous Novel Mutations of LRP5 and TSPAN12 in a Case of Familial Exudative Vitreoretinopathy.

Familial exudative vitreoretinopathy and osteoporosis pseudoglioma syndrome are conditions that result from mutations in the LRP5 gene. Persistent fetal vasculature is a rare congenital malformation that can mimic end-stage familial exudative vitreoretinopathy. The authors report a case of familial exudative vitreoretinopathy in the spectrum of osteoporosis pseudoglioma syndrome associated with novel mutations of the LRP5 and TSPAN12 genes that resulted in a phenotype similar to bilateral persistent fetal vasculature. Both conditions can result in bilateral early-onset blindness. A high index of suspicion, dilated fundus examination and angiography of the parents, and genetic testing are necessary to ensure a correct diagnosis.

Potential blindness in children of patients with hereditary bone disease.

Mono- and bi-allelic mutations in the low-density lipoprotein receptor related protein 5 (LRP5) may cause osteopetrosis, autosomal dominant and recessive exudative vitreoretinopathy, juvenile osteoporosis, or persistent hyperplastic primary vitreous (PHPV). We report on a child affected with PHPV and carrying compound mutations. The father carried the splice mutation and suffered from severe bone fragility since childhood. The mother carried the missense mutation without any clinical manifestations. The genetic diagnosis of their child allowed for appropriate treatment in the father and for the detection of osteopenia in the mother. Mono- and bi-allelic mutations in LRP5 may cause osteopetrosis, autosomal dominant and recessive exudative vitreoretinopathy, juvenile osteoporosis, or PHPV. PHPV is a component of persistent fetal vasculature of the eye, characterized by highly variable expressivity and resulting in a wide spectrum of anterior and/or posterior congenital developmental defects, which may lead to blindness. We evaluated a family diagnosed with PHPV in their only child. The child presented photophobia during the first 3 weeks of life, followed by leukocoria at 2 months of age. Molecular resequencing of NDP, FZD4, and LRP5 was performed in the child and segregation of the observed mutations in the parents. At presentation, fundus examination of the child showed a retrolental mass in the right eye. Ultrasonography revealed retinal detachment in both eyes. Thorough familial analysis revealed that the father suffered from many fractures since childhood without specific fragility bone diagnosis, treatment, or management. The mother was asymptomatic. Molecular analysis in the proband identified two mutations: a c.[2091+2T>C] splice mutation and c.[1682C>T] missense mutation. We report the case of a child affected with PHPV and carrying compound heterozygous LRP5 mutations. This genetic diagnosis allowed the clinical diagnosis of the bone problem to be made in the father, resulting in better management of the family. It also enabled preventive treatment to be prescribed for the mother and accurate genetic counseling to be provided.

Frizzled-4 Variations Associated with Retinopathy and Intrauterine Growth Retardation: A Potential Marker for Prematurity and Retinopathy.

PURPOSE: To present the association between mutations affecting the Wnt-signaling receptor protein (FZD4), inherited vitreoretinopathies, and retinopathy of prematurity (ROP). DESIGN: Retrospective analysis of prospective samples at a tertiary referral center. PARTICIPANTS: Patients referred to our practice for management of a variety of pediatric vitreoretinopathies were offered participation in an ophthalmic biobank (421 participants with vitreoretinopathies were included in this study). Full-term healthy infants (n = 98) were recruited to the study as controls. METHODS: Patients with various vitreoretinopathies were prospectively enrolled in an ophthalmic biobank, approved by the Human Investigation Committee at William Beaumont Hospital. Retrospective genetic analysis of the FZD4 gene was performed (Sanger sequencing). Participants with a diagnosis of familial exudative vitreoretinopathy (FEVR), Norrie disease, Coats' disease, bilateral persistent fetal vasculature, and ROP were reviewed for the presence of a FZD4 variant. Data retrieval included status of retinopathy (including staging when possible), gestational age (GA), birth weight (BW) (when available), and family and birth histories. MAIN OUTCOME MEASURES: The association of FZD4 variants with the presence of vitreoretinopathy. RESULTS: The sequence variation p.[P33S(;)P168S] is the most prevalent FZD4 variant and is statistically significant for ROP and FEVR (P = 4.6E-04 and P = 2.4E-03, respectively) compared with full-term newborns (P = 1.7E-01). In addition, infants expressing the sequence variation tended to have significantly lower BWs for respective GA (P = 0.04). This suggests that the FZD4 p.[P33S(;)P168S] variant may be a risk factor for retinopathy and restricted intrauterine growth. CONCLUSIONS: Testing for FZD4 gene mutations is useful in patients with suspected FEVR and ROP. The relatively high prevalence of the p.[P33S(;)P168S] variant in ROP and intrauterine growth restriction suggests that it also may be a marker for increased risk of developing ROP and preterm birth.

EphrinB2 controls vessel pruning through STAT1-JNK3 signalling.

Angiogenesis produces primitive vascular networks that need pruning to yield hierarchically organized and functional vessels. Despite the critical importance of vessel pruning to vessel patterning and function, the mechanisms regulating this process are not clear. Here we show that EphrinB2, a well-known player in angiogenesis, is an essential regulator of endothelial cell death and vessel pruning. This regulation depends upon phosphotyrosine-EphrinB2 signalling repressing c-jun N-terminal kinase 3 activity via STAT1. JNK3 activation causes endothelial cell death. In the absence of JNK3, hyaloid vessel physiological pruning is impaired, associated with abnormal persistence of hyaloid vessels, defective retinal vasculature and microphthalmia. This syndrome closely resembles human persistent hyperplastic primary vitreus (PHPV), attributed to failed involution of hyaloid vessels. Our results provide evidence that EphrinB2/STAT1/JNK3 signalling is essential for vessel pruning, and that defects in this pathway may contribute to PHPV.

Novel mutation in TSPAN12 leads to autosomal recessive inheritance of congenital vitreoretinal disease with intra-familial phenotypic variability.

Developmental malformations of the vitreoretinal vasculature are a heterogeneous group of conditions with various modes of inheritance, and include familial exudative vitreoretinopathy (FEVR), persistent fetal vasculature (PFV), and Norrie disease. We investigated a large consanguineous kindred with multiple affected individuals exhibiting variable phenotypes of abnormal vitreoretinal vasculature, consistent with the three above-mentioned conditions and compatible with autosomal recessive inheritance. Exome sequencing identified a novel c.542G > T (p.C181F) apparently mutation in the TSPAN12 gene that segregated with the ocular disease in the family. The TSPAN12 gene was previously reported to cause dominant and recessive FEVR, but has not yet been associated with other vitreoretinal manifestations. The intra-familial clinical variability caused by a single mutation in the TSPAN12 gene underscores the complicated phenotype-genotype correlation of mutations in this gene, and suggests that there are additional genetic and environmental factors involved in the complex process of ocular vascularization during embryonic development. Our study supports considering PFV, FEVR, and Norrie disease a spectrum of disorders, with clinical and genetic overlap, caused by mutations in distinct genes acting in the Norrin/ß-catenin signaling pathway.

Varied manifestations of persistent hyperplastic primary vitreous with graded somatic mosaic deletion of a single gene.

PURPOSE: Persistent hyperplastic primary vitreous (PHPV) represents a developmental eye disease known to have diverse manifestations ranging from a trivial remnant of hyaloid vessels to a dense fibrovascular mass causing lens opacity and retinal detachment. PHPV can be modeled in mice lacking individual genes, but certain features of such models differ from the clinical realm. For example, mice lacking the Arf gene have uniformly severe disease with consistent autosomal recessive disease penetrance. We tested whether the graded somatic loss of Arf in a subset of cells in chimeric mice mimics the range of disease in a non-heritable manner. METHODS: Wild type ↔ Arf(-/-) mouse chimeras were generated by morulae fusion, and when the mice were 10 weeks old, fundoscopic, slit-lamp, and histological evaluations were performed. The relative fraction of cells of the Arf(-/-) lineage was assessed with visual, molecular genetic, and histological analysis. Objective quantification of various aspects of the phenotype was correlated with the genotype. RESULTS: Sixteen chimeras were generated and shown to have low, medium, and high contributions of Arf(-/-) cells to tail DNA, the cornea, and the retinal pigment epithelium (RPE), with excellent correlation between chimerism in the tail DNA and the RPE. Phenotypic differences (coat color and severity of eye disease) were evident, objectively quantified, and found to correlate with the contribution of Arf(-/-) cells to the RPE and tail-derived DNA, but not the cornea. CONCLUSIONS: Generating animals composed of different numbers of Arf(-/-) cells mimicked the range of disease severity observed in patients with PHPV. This establishes the potential for full manifestations of PHPV to be caused by somatic mutations of a single gene during development.

A distant, cis-acting enhancer drives induction of Arf by Tgfß in the developing eye.

The Arf tumor suppressor represents one of several genes encoded at the Cdkn2a and Cdkn2b loci in the mouse. Beyond its role blunting the growth of incipient cancer cells, the Arf gene also plays an essential role in development: its gene product, p19(Arf), is induced by Tgfß2 in the developing eye to dampen proliferative signals from Pdgfrß, which effect ultimately fosters the vascular remodeling required for normal vision in the mouse. Mechanisms underlying Arf induction by Tgfß2 are not fully understood. Using the chr4(Δ70 kb/Δ70 kb) mouse, we now show that deletion of the coronary artery disease (CAD) risk interval lying upstream of the Cdkn2a/b locus represses developmentally-timed induction of Arf resulting in eye disease mimicking the persistent hyperplastic primary vitreous (PHPV) found in Arf-null mice and in children. Using mouse embryo fibroblasts, we demonstrate that Arf induction by Tgfß is blocked in cis to the 70 kb deletion, but Arf induction by activated RAS and cell culture "shock" is not. Finally, we show that Arf induction by Tgfß is derailed by preventing RNA polymerase II recruitment following Smad 2/3 binding to the promoter. These findings provide the first evidence that the CAD risk interval, located at a distance from Arf, acts as a cis enhancer of Tgfß2-driven induction of Arf during development.

Deletion of HIF-1α partially rescues the abnormal hyaloid vascular system in Cited2 conditional knockout mouse eyes.

PURPOSE: Cited2 (CBP/p300-interacting transactivators with glutamic acid (E) and aspartic acid (D)-rich tail 2) is a member of a new family of transcriptional modulators. Cited2 null embryos exhibit hyaloid hypercellularity consisting of aberrant vasculature in the eye. The purpose of the study is to address whether abnormal lenticular development is a primary defect of Cited2 deletion and whether deletion of hypoxia inducible factor (HIF)-1α or an HIF-1α target gene, vascular endothelial growth factor (VEGF), could rescue abnormal hyaloid vascular system (HVS) in Cited2 deficient adult eyes. METHODS: Le-Cre specific Cited2 knockout (Cited2(CKO)) mice with or without deletion of HIF-1α or VEGF were generated by standard Cre-Lox methods. Eyes collected from six-eight weeks old mice were characterized by Real Time PCR and immunohistological staining. RESULTS: Cited2(CKO) mice had smaller lenses, abnormal lens stalk formation, and failed regression of the HVS in the adult eye. The eye phenotype had features similar to persistent hyperplastic primary vitreous (PHPV), a human congenital eye disorder leading to abnormal lenticular development. Deletion of HIF-1α or VEGF in Cited2 knockout eyes partially rescued the abnormal HVS but had no effect on the smaller lens and abnormal lens stalk differentiation. Intravitreal injection of Topotecan (TPT), a compound that inhibits HIF-1α expression, partially eliminated HVS defects in Cited2(CKO) lenses. CONCLUSIONS: Abnormal HVS is a primary defect in Cited2 knockout mice, resulting in part from dysregulated functions of HIF-1 and VEGF. The Cited2(CKO) mouse line could be used as a novel disease model for PHPV and as an in vivo model for testing potential HIF-1 inhibitors.

Nine genes that may contribute to partial trisomy (6)(p22→pter) and unique presentation of persistent hyperplastic primary vitreous with retinal detachment.

We report on a newborn girl with facial anomalies, a congenital heart defect, severe pre- and postnatal growth retardation, feeding problems, and persistent hyperplastic primary vitreous. Cytogenetic analysis by high resolution GTG banding showed extra chromosomal material on the short arm of one chromosome 1 of the patient, but neither parent. SKY and CGH analysis demonstrated that the patient had a de novo 46,XX, der(1)t(1;6)(p36.3; p22). Compared with previously reported cases of partial trisomy 6p22 syndrome, this patient exhibited a unique condition for this syndrome: persistent hyperplastic primary vitreous (PHPV) with retinal detachment. The human genome database was searched for candidate genes and we propose the following nine genes located in the 6p22→6pter region for their potential contribution to the phenotype of partial trisomy 6p22→pter and persistent hyperplastic primary vitreous (PHPV) with retinal detachment: Forkhead box Q1 (FOXQ1), FOXF2, FOXC1, NRN1, EDN1, ATXN1, DEK oncogene, E2F3, and NRNS1.

Submicroscopic deletion in 7q31 encompassing CADPS2 and TSPAN12 in a child with autism spectrum disorder and PHPV.

We performed array comparative genomic hybridization utilizing a whole genome oligonucleotide microarray in a patient with the autism spectrum disorders (ASDs) and persistent hyperplastic primary vitreous (PHPV). Submicroscopic deletions in 7q31 encompassing CADPS2 (Ca(2+) -dependent activator protein for secretion 2) and TSPAN12 (one of the members of the tetraspanin superfamily) were confirmed. The CADPS2 plays important roles in the release of neurotrophin-3 and brain-derived neurotrophic factor. Mutations in TSPAN12 are a relatively frequent cause of familial exudative vitreoretinopathy. We speculate that haploinsufficiency of CADPS2 and TSPAN12 contributes to ASDs and PHPV, respectively.

A novel NDP mutation in an infant with unilateral persistent fetal vasculature and retinal vasculopathy.

BACKGROUND: Mutations in the Norrie Disease gene, Norrie Disease Pseudoglioma (NDP) lead to a phenotypically heterogeneous group of retinopathies. We report a novel mutation in the NDP gene identified in a patient whose clinical presentation was suggestive of unilateral persistent fetal vasculature (PFV). MATERIALS AND METHODS: Ophthalmic examinations, ocular ultrasounds and sequence analysis of the exons of the NDP gene on peripheral blood DNA were performed. RESULTS: A four-month-old boy was referred to our institution for presumed unilateral retinoblastoma. The clinical and ultrasonographic exams were consistent with PFV and retinal detachment of the left eye as well as retinal fibrovascular changes in the right eye. A vitrectomy of the left eye revealed the absence of a retrolenticular stalk and mutation analysis of the NDP gene of the proband and mother demonstrated a novel missense mutation at codon 66, designated as c. 196G > A at the cDNA level and E66K at the protein level. CONCLUSION: We report a novel mutation in the NDP gene in a patient whose presentation demonstrates the phenotypic heterogeneity of NDP-related disorders.

Phenotypic overlap of familial exudative vitreoretinopathy (FEVR) with persistent fetal vasculature (PFV) caused by FZD4 mutations in two distinct pedigrees.

PURPOSE: To describe a severe familial exudative vitreoretinopathy (FEVR) phenotype seen in infancy that resembles persistent fetal vasculature (PFV) caused by mutations in the FZD4 gene in two pedigrees with high intrafamilial variability. METHODS: Three infants presented with features compatible with bilateral PFV. Eye examinations from the affected children and their relatives were reviewed retrospectively (follow-up:18 months-9 years). Mutation screening was performed using direct sequencing of the FZD4, LRP5 and NDP genes. RESULTS: Bilateral retinal folds extending from the optic nerve to the inferotemporal aspect of the lens mimicing PFV were observed in two of the three affected children before the age of two months. The third child was examined at birth, and the avascular peripheral retina treated with diode laser within one week of age, with subsequent arrest of the disease process. A FZD4 mutation, M493_W494del, was identified in one affected child in pedigree 1, and a novel missense mutation, I114T, was detected in 2 affected children in pedigree 2; while no mutations were found in NDP or LRP5 genes in the 3 affected children. In both pedigrees, at least one affected relative was asymptomatic and failed to show the characteristic avascular changes of FEVR. CONCLUSIONS: The clinical features in the three children and their relatives with a documented FZD4 mutation support the previous reports of a high degree of intrafamilial and interfamilial variability in FEVR. In extreme cases with very early onset, the development of a retinal fold can mimic PFV, a non-hereditary condition with rare exception.