Multifocal hypopigmented retinal pigment epithelial lesions in incontinentia pigmenti.

BACKGROUND: Incontinentia pigmenti (IP) can manifest with retinal detachment in children and can simulate retinoblastoma. The authors report a clinicopathologic correlation of IP and illustrate the retinal pigment epithelium (RPE) alterations that may be useful in establishing the diagnosis. METHODS: A 30-month-old reportedly healthy girl developed strabismus and was discovered to have total retinal detachment in the left eye. Intraocular calcification was found on ultrasonography and computed tomography, suggestive of retinoblastoma. RESULTS: Ophthalmoscopy of the right eye revealed sector distribution of approximately 70 elongated, linear hypopigmented lesions of the RPE located in the peripheral superotemporal, inferotemporal, and superonasal quadrants and measuring 300 microm or less in basal dimension. The left eye had a total retinal detachment, vitreous traction, perivascular exudation, and iris neovascularization. Despite the lack of medical history in this patient, skin examination revealed classic cutaneous findings of IP The enucleated left globe displayed tractional retinal detachment with vitreoretinal neovascularization and nonspecific RPE papillary proliferation. Scattered minor foci of intraretinal calcification were observed. There was no sign of retinoblastoma. CONCLUSIONS: IP can closely simulate retinoblastoma with retinal detachment and minor intraocular calcification. In this case, the classic cutaneous manifestations combined with the fine linear hypopigmented RPE foci were important in suggesting the diagnosis of IP.

Gene discovery in the embryonic chick retina.

PURPOSE: The chick embryo is a powerful model system for the study of retinal development. However, analysis of gene expression in the chick retina has lagged behind biological studies. The purpose of this study was to identity and characterize genes expressed in the chick embryo retina as candidate molecules involved in the development and function of photoreceptors and other retinal cell types. METHODS: RNA from embryonic day (ED) 18 White Leghorn chick embryo retinae was used to generate an oligo dT-primed cDNA library. Bacterial colonies representing five thousand individual clones were arrayed onto nylon membranes using a microarray robot. Replicate membranes were hybridized with cDNA probes synthesized from ED 18 retina, brain and liver. Clones that appeared preferentially expressed in retina were identified by homology searches, and their spatial and temporal expression patterns were analyzed by in situ hybridization. RESULTS: Two hundred and seventy-two clones were identified. Approximately forty percent of the clones represented potential novel genes, including ESTs, hypothetical proteins and clones with no assigned identities. Furthermore, many genes were identified that are the putative chick orthologues of genes cloned from other species. We determined the expression pattern of several clones for which sequence homologies suggested possible roles in transcriptional regulation, apoptosis or intercellular signaling. Their corresponding mRNAs were expressed in the embryonic retina in topographically specific, developmentally regulated patterns. CONCLUSIONS: We identified and characterized genes in the chick embryo retina using a combination of microarray analysis and in situ hybridization. Analysis of the expression patterns suggests involvement of several of these genes in key events during embryogenesis.