Peters anomaly in cri-du-chat syndrome

The cri-du-chat syndrome is a rare genetic disorder caused by deletions in the short arm of chromosome 5. It presents with a distinctive catlike high-pitched cry, psychomotor delays, microcephaly, craniofacial abnormalities, and, in many cases, ocular findings. We report the first child with cri-du-chat and the findings of unilateral corneal staphyloma due to Peters anomaly and retinal dysplasia.

Effects of L1 retrotransposon insertion on transcript processing, localization and accumulation: lessons from the retinal degeneration 7 mouse and implications for the genomic ecology of L1 elements

The retinal degeneration 7 (rd7) mouse is a naturally occurring model of enhanced S-cone syndrome, Goldman-Favre syndrome and clumped pigmentary retinopathy in humans, allelic disorders caused by inactivation of a photoreceptor-specific nuclear hormone receptor, NR2E3. We show here that the rd7 mutation arose from the antisense insertion of a long interspersed nuclear element (LINE-1) (or L1) into exon 5 of the mouse Nr2e3 gene. L1 insertion blocks splicing of Nr2e3 intron 5 by separating an inefficient splice donor from essential splicing enhancers within exon 5, with the result that incompletely spliced transcripts accumulate to high levels at the mutant Nr2e3 locus in photoreceptor nuclei. The high efficiency of transcription through the 7 kb L1 was unexpected and led us to compare the effect on transcript abundance of sense or antisense L1 insertions in transfected cells. In a variety of sequence contexts antisense L1 insertions had little or no effect on transcript levels or the production of full-length transcripts, whereas sense L1 insertions reduced transcript levels from several-fold to more than 10-fold. A bioinformatic analysis of all mouse L1s shows a approximately 2-fold under-representation of L1s in introns when compared with bulk genomic DNA, and, within introns, a further approximately 2-fold under-representation of sense when compared with antisense L1s. Interestingly, there is no evidence for orientation-specific positive or negative selection within any subregions of the L1 element. These data suggest that L1s have evolved to present the host transcriptional machinery with a minimally disruptive profile in the antisense orientation such that antisense intronic L1s often escape purifying negative selection.

Periventricular leukomalacia and retinopathy in a term infant born to a mother with asthma

A male child, born at 37+5 gestational weeks (GWs) (birthweight 2000g) after intrauterine growth retardation (IUG; -3 SD), to a mother treated during pregnancy for asthma, developed periventricular leukomalacia and retinopathy with total retinal detachment in the left eye and partial detachment in the right eye. Apart from basic asthma treatment with terbutalin, budesonid, and fenoterolhydrobromid throughout the pregnancy, she was treated with intravenous or oral cortisone for 6.5 weeks from 28+5 GWs. In addition she developed deep venous thrombosis at 29 GWs and was treated with heparin until delivery. Psychotic symptoms during the 31st GW were treated with diazepam, haloperidol, and levomepromazin. Functional sequelae for the child were visual impairment (visual acuity 5/60), uneven intellectual profile (Wechsler Pre-school and Primary Scale of Intelligence, Verbal IQ 94 and Performance IQ 32 at 8y of age), and autistic-like behaviour. The possibility that pre- and perinatal risk factors (e.g. severe maternal illness, IUGR, and cortisone treatment) in a term infant may create conditions for developing eye and brain pathologies commonly closely related to preterm birth should be considered.

[Congenital retinal folds in different clinical cases]

We present 12 clinical cases of congenital retinal folds with different etiologies: posterior primitive vitreous persistency and hyperplasia (7 cases),retinocytoma (1 case). retinopathy of prematurity (1 case), astrocytoma of the retina (1 case), retinal vasculitis (1 case), Goldmann-Favre syndrome (1 case). Etiopathogenic and nosological aspects are discussed; the congenital retinal folds are interpreted as a symptom in a context of a congenital or acquired vitreo-retinal pathology.

Excess cone cell proliferation due to lack of a functional NR2E3 causes retinal dysplasia and degeneration in rd7/rd7 mice

The rd7 mouse is a model for hereditary retinal degeneration characterized clinically by retinal spotting throughout the fundus and late onset retinal degeneration, and histologically by retinal dysplasia manifesting as folds and whorls in the photoreceptor layer. This study demonstrates that the rd7 phenotype results from a splicing error created by a genomic deletion of an intron and part of an exon. Hematoxylin/eosin staining of rd7 tissue shows that the whorls in the outer nuclear layer of the retina do not appear during embryonic development but manifest by postnatal day 12.5 (P12.5). Furthermore, in situ hybridization data indicates that the Nr2e3 message is first present at barely discernable levels at embryonic day 18.5, becomes abundant by P2.5, and reaches maximal adult levels by P10.5. Results from these experiments indicate that Nr2e3 message is expressed prior to the development of S-cones. This data coincides with studies in humans showing that mutations in Nr2e3 result in a unique type of retinal degeneration known as enhanced S-cone syndrome, where patients have a 30-fold increase in S-cone sensitivity compared to normal. Immunohistochemical staining of cone cells demonstrates that rd7 retinas have an increased number of cone cells compared to wild-type retinas. Thus, Nr2e3 may function by regulating genes involved in cone cell proliferation, and mutations in this gene lead to retinal dysplasia and degeneration by disrupting normal photoreceptor cell topography as well as cell-cell interactions.

Oxygen-induced retinopathy in the rat: hemorrhages and dysplasias may lead to retinal detachment

Rearing neonatal rats in hyperoxia induces the development of retinal hemorrhages and retinal dysplasia. Albino rats were placed in 80% oxygen immediately after birth and were exposed for either 5, 10, or 14 days, followed by sacrifice or exposure to normoxia for an additional 2, 4, 5, 7, 8, 10, 38, 45 or 56 days. Control rats were simultaneously raised in room air and sacrificed at the same times. All animals were enucleated and their eyes processed for light and electron microscopy. Eyecups were trimmed to facilitate cross-sectioning of the retina in the vertical meridian. No control rats showed signs of retinal hemorrhages or of dysplastic folds or rosettes. Nor did the retinas of rats killed immediately after oxygen exposure contain hemorrhages, but the incidence of retinal folds or rosettes in this group was 54%. For rats exposed to combinations of hyperoxia and brief normoxia (10 days or less), 40% suffered hemorrhages and 50% developed retinal folds or rosettes. Although hemorrhages were more prominent in rats subjected to longer periods of oxygen (73% of all rats exposed for 14 days followed by brief normoxia vs. 6% of those exposed for 5 days followed by brief normoxia), the incidence decreased with time post-exposure in room air. Hemorrhages occurred in 100% of the rats raised in oxygen for 14 days followed by 2 days in room air, and decreased to 50% by 7 days in room air and to 0% by 38 days, indicating a spontaneous resolution with time. In each case, the blood appeared to leak from the newly-forming vessels of the deep capillary net, with most of the red blood cells migrating to the subretinal space. Retinal fold or rosette formation, indicative of developmental dysplasia, occurred in a fraction of virtually all groups of exposed rats, and persisted at the longest post-exposure periods. These two manifestations of oxygen-induced retinopathy are emphasized because they lead to an abnormal separation of the retina from the epithelial layer, which may increase the likelihood of the most serious consequence of ROP--retinal detachment. In fact, all rats that endured post-exposure periods of 38 days or longer before sacrifice exhibited retinal detachment.

[Immunopathologic study of retinal detachment with vitreo-retinal proliferation]

Immunopathological studies were performed on biopsies or autopsies of pars plana samples from patients with retinal detachment, with or without vitreo-retinal proliferation. Immunoglobulins and complement deposits have been found in vitreo retinal proliferation, together with a deviant expression of HLA-DR and DQ antigens by pigmented epithelial cells of the ciliary body. Gamma interferon is able to induce this expression in vitro, and the inducing effect of this lymphokine and other mediators has been tested on pigment epithelium cultures. Cultured pigment epithelial cells expressed HLA-DR and DQ antigens after being stimulated by very low doses of gamma interferon. The precise target of this immune reaction is still impossible to determine, but its consequences could be the release of growth factors as FGF, which has been found at very high levels in pigmented and non pigmented cells of pars plana and ciliary processes. Our work asserts the existence of auto-immune phenomena in retinal detachment with vitreo-retinal proliferation as well as in proliferative diabetic retinopathy, their exact involvement remaining to determine.