Heterozygous <i>E168d2/</i>+ mice, but not <i>R90W/</i>+, develop dominant retinopathy.

<p><b>A–P</b>. Retinal morphology of the indicated heterozygous mutant mice was assessed by H&E staining of paraffin embedded sagittal sections at P14, 1 mo, 3 mo, and 6 mo. Shortened photoreceptor outer segments and ONL cell loss are apparent in <i>E168d2/+</i> retina only. <b>Q–T</b>. ONL thickness was assessed by spider graph morphometry at the indicated ages. <i>E168d2/+</i> (red line) shows progressive thinning of the ONL through 6 mo, while it's low expression subline, <i>E168d2neo/+</i> (blue line), and <i>R90W/+</i> (green line) do not. Significant differences in overall ONL thickness were determined by testing genotype*distance interactions (by two-way ANOVA). Significant interactions were observed at P14 (p = 0.03) and 6 mo (p = 0.03), followed by testing individual comparisons to <i>WT:</i> *p<0.05. INF-inferior retina, SUP-superior retina. <b>U–W</b>. The ultra structure of rod outer segment (OS) and nuclear morphology was assessed by transmission electron microscopy. Micrographs of rod outer segments proximal to RPE from <i>WT</i> control (<b>U</b>), <i>E168d2/+</i> (<b>V</b>) and <i>E168d2neo/+</i> mice (<b>W</b>). <i>E168d2/+</i> OS's are highly disorganized showing ‘wave-like’ OS membrane stacks (asterisks), vesiculated membranes ‘+’ and vertically oriented OS membranes (triangles). <i>E168d2neo/+</i> OS's only show minor ‘wave-like’ patterns and vesiculated membranes.