An NR2F1-dependent retinoic acid network controls retinal specialization in mice and reveals foveal hypoplasia in patients with BBSOAS

ABSTRACT: The molecular programs that establish specialized retinal regions during development are essential for high-acuity vision, yet how their disruption contributes to human visual disorders remains poorly understood. Bosch-Boonstra-Schaaf optic atrophy syndrome (BBSOAS), caused by pathogenic variants in NR2F1 and characterized by visual impairment, provides an opportunity to investigate these mechanisms. Using single-cell RNA sequencing of three complementary Nr2f1 mouse models, including two carrying patient-specific mutations, we identified a shared Nr2f1 -dependent transcriptional program enriched in retinoic acid (RA) pathway genes. Loss or mutation of Nr2f1 disrupted the spatial organization of RA signaling, most prominently by expanding the dorso-equatorial Cyp26a1 expression domain into ventral retina and reducing ventral determinants such as Vax2 . These molecular changes were associated with altered dorso-ventral distribution of S-and M-opsin-expressing cone photoreceptors. We further demonstrate that human NR2F1 binds a conserved regulatory region upstream of CYP26A1 , supporting its direct role in regulating local RA availability. Finally, high-resolution optical coherence tomography in individuals with BBSOAS revealed reproducible foveal abnormalities, including a smaller and shallower foveal pit and increased central retinal thickness, consistent with foveal hypoplasia. These findings uncover a previously unrecognized retina-intrinsic component of BBSOAS visual pathology and establish an NR2F1-RA/CYP26A1 regulatory axis linking developmental retinal regionalization to human foveal specialization.