A biometric survey of known and prospective murine models of posterior microphthalmia-nanophthalmia

Abstract

Posterior microphthalmia and nanophthalmia are related genetic conditions that disrupt ocular growth. Here, we conducted a biometric analysis of mouse models to assess shared features of these diseases. Three known microphthalmia alleles (Mfrp^rd6, Prss56^glcr4, and Adipor1^tm1Dgen) and two prospective alleles (C1qtnf5^{tm1.1(KOMP)Vlcg} and Prss56^em2(IMPC)J) were introgressed onto the C57BL/6J (B6) genetic background and compared to B6 mice at 1 through 12 months of age. Biometric parameters obtained using optical coherence tomography were analyzed statistically to identify strain differences. Fundus imaging and histological analyses were performed to assess ocular morphology. Mfrp^rd6, Prss56^glcr4, and Prss56^em2(IMPC)J mice had significantly shorter axial and posterior lengths, and longer anterior chamber depth compared to controls at all ages studied. Adipor1^tm1Dgen mice exhibited similar, but less severe, biometric changes. Axial length was not significantly changed in C1qtnf5^{tm1.1(KOMP)Vlcg} mice, but reduced anterior chamber depth and increased lens thickness were observed at one month of age. Lens and corneal thicknesses were otherwise unchanged in the models as compared to B6 controls. Corneal radius of curvature, examined at 4 months of age, was significantly decreased in all models relative to controls. Micropthalmia was observed independent of retinal degeneration (Mfrp^rd6, Adipor1^tm1Dgen) or retinal thickening (Prss56 mutants). Prss56 mutants developed retinal folds that were absent from other mutants and controls. We conclude that, in mice, Mfrp, Prss56, and Adipor1 mutations yield similar microphthalmia phenotypes involving both the anterior and posterior eye. Changes to anterior chamber depth, lens thickness, and corneal curvature in C1qtnf5^{tm1.1(KOMP)Vlcg} mice suggest a role of C1qtnf5 in anterior ocular growth.