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Abstract #8334 Published in IGR 4-3
Pax6 heterozygous eyes show defects in chamber angle differentiation that are associated with a wide spectrum of other anterior eye segment abnormalities
Baulmann DC; Ohlmann A; Flugel-Koch C; Goswami S; Cvekl A; Tamm ERMechanisms of Development 2002; 118: 3-17
The development of the chamber angle was studied in the eyes of heterozygous Pax6acZ/+ mutant mice. Mutations in PAX6 cause aniridia, a condition that is frequently associated with glaucoma, a blinding disease that may be associated with chamber angle defects. Mesenchymal cells were seen in the chamber angle at P1-P5. In wild-type mice, these cells differentiated into typical trabecular meshwork (TM) cells next to Schlemm's canal. In Pax6lacZ/+ mice, TM cells remained undifferentiated and Schlemm's canal was absent. From P1 to P4, staining for β-galactosidase and immunoreactivity for Pax6 were observed in chamber angle mesenchyme, but were absent later. Cultured murine TM cells expressed Pax6. The defects in chamber angle and TM differentiation were associated with a wide spectrum of other anterior eye defects, which included various degrees of iris hypoplasia and corneal haze, isolated iridocorneal adhesions and atypical coloboma, and a vascularized cornea in all adult animals. A third of the animals showed Peters' anomaly including corneal opacity and iridocorneal adhesions. The separation of the lens from the cornea was incomplete, and epithelial layers of lens and cornea were continuous. Pax6 activity is directly required for differentiation of the chamber angle. Variations in phenotype of Pax6lacZ/+ mice appear not to involve direct dominant-negative or dose-dependent effects.
E.R. Tamm, MD, Department of Anatomy, University of Erlangen-Nurnberg, Universitatsstrasse 19, D-91054 Erlangen, Germany. ernst.tamm@anatomie2.med.uni-erlangen.de
Classification:
1.2 Population genetics (Part of: 1 General aspects)
9.1.3 Syndromes of Axenfeld, Rieger, Peters, aniridia (Part of: 9 Clinical forms of glaucomas > 9.1 Developmental glaucomas)
