BackgroundMutations in candidate genes that encode for a ligand (NDP) and receptor complex (FZD4, LRP5 and TSPAN12) in the Norrin β-catenin signaling pathway are involved in the pathogenesis of familial exudative vitreoretinopathy (FEVR, MIM # 133780). Recently, a transcription factor (ZNF408) has also been implicated in FEVR. We had earlier characterized the variations in NDP among FEVR patients from India. The present study aimed at understanding the involvement of the remaining genes (FZD4, TSPAN12 and ZNF408) in the same cohort.MethodsThe DNA of 110 unrelated FEVR patients and 115 unaffected controls were screened for variations in the entire coding and untranslated regions of these 3 genes by resequencing. Segregation of the disease-associated variants was assessed in the family members of the probands. The effect of the observed missense changes were further analyzed by SIFT and PolyPhen-2 scores.ResultsThe screening of FZD4, TSPAN12 and ZNF408 genes identified 11 different mutations in 15/110 FEVR probands. Of the 11 identified mutations, 6 mutations were novel. The detected missense mutations were mainly located in the domains which are functionally crucial for the formation of ligand-receptor complex and as they replaced evolutionarily highly conserved amino acids with a SIFT score < 0.005, they are predicted to be pathogenic. Additionally 2 novel and 16 reported single nucleotide polymorphisms (SNP) were also detected.ConclusionsOur genetic screening revealed varying mutation frequencies in the FZD4 (8.0 %), TSPAN12 (5.4 %) and ZNF408 (2.7 %) genes among the FEVR patients, indicating their potential role in the disease pathogenesis. The observed mutations segregated with the disease phenotype and exhibited variable expressivity. The mutations in FZD4 and TSPAN12 were involved in autosomal dominant and autosomal recessive families and further validates the involvement of these gene in FEVR development.Electronic supplementary materialThe online version of this article (doi:10.1186/s12886-016-0236-y) contains supplementary material, which is available to authorized users.

Glaucoma is a leading cause of blindness affecting up to million people worldwide. High intraocular pressure (IOP) is a major risk factor for glaucoma. Inefficient aqueous humor (AqH) outflow resulting from structural or functional alterations in ocular drainage tissues are well established to cause high IOP, but the genes and pathways involved are poorly understood. We previously demonstrated that mutations in the gene encoding the serine protease PRSS56 induces ocular angle-closure and high IOP in mice and identified reduced ocular axial length as a potential contributing factor. Here we show that Prss56-/mice also exhibits an abnormal iridocorneal angle configuration characterized by a posterior shift of ocular drainage structures relative to the ciliary body and iris. Notably, we show that retina-derived PRSS56 is required between postnatal days 13 and 18 for proper iridocorneal configuration and that abnormal positioning of the ocular drainage tissues is not dependent on ocular size reduction in Prss56-/mice. Furthermore, we demonstrate that the genetic context modulates the severity of IOP elevation in Prss56 mutant mice and describe a progressive degeneration of ocular drainage tissues that likely contributes to the exacerbation of the high IOP phenotype observed on the C3H/HeJ genetic background. Finally, we identified five rare PRSS56 variants associated with human primary congenital glaucoma, a condition characterized by abnormal development of the ocular drainage structures. Collectively, our findings point to a role for PRSS56 in the development and maintenance of ocular drainage tissues and IOP homeostasis, and provide new insights into glaucoma pathogenesis.

Background: To understand the pathogenesis of a central corneal dermoid (CD) in a 12-day-old child, a comparison of CD specimen was done with limbal dermoid (LD) and cadaveric corneal (CC) specimens by immuno-histochemical staining. Methods: The child underwent penetrating keratoplasty for visual rehabilitation. The corneal tissue was sent for histo-pathological and immunochemistry evaluation. The corneal specimen obtained was compared the origin of central CD with LD and CC based on their antigenic expression profile. Results: Clinically over a period of 75 months post operatively the child maintained a clear graft. Hematoxylin and Eosin staining of LD had a typical morphology including stratified keratinized epithelium, hair shaft with pilo sebaceous glands, eccrine sweat glands, lymphocytes, and blood vessels. Immuno-histochemical staining showed positive stain for Cytokeratin 3 epithelial marker in the epithelium of CC, LD, and CD. Smooth muscle maker (SMA) was identified in LD and CD but not in the CC as it is devoid of blood vessels. Limbal stem cell maker (P63) was detected only in LD. Vimentin, a mesenchymal stem cell marker stained positively in all three tissues of CC, LD, and CD. Conclusions: Corneal dermoid showed positive staining for mesodermal tissue components compared to both ectodermal and mesodermal components in limbal dermoid suggesting possibly a different origin of corneal dermoid