| Mechanism/biological process | Evidence summary | Suggested GO Biological Process term(s) | Suggested GO Cellular Component term(s) | Suggested CL cell type term(s) | Suggested UBERON anatomical structure term(s) | Source(s) |
|---|---|---|---|---|---|---|
| Early retinogenesis defect | NR2F1 pathogenic variants are associated with a developmental ocular phenotype; human deep phenotyping and mouse data support abnormal early retinal development with decreased retinal ganglion cell density, consistent with congenital visual impairment rather than classic progressive optic neuropathy. | retina development; neural retina development; retinal ganglion cell differentiation; eye morphogenesis | neural retina; ganglion cell layer; optic nerve head | retinal ganglion cell; retinal progenitor cell | retina; neural retina; optic nerve head; eye | (pqac-00000000, pqac-00000014, pqac-00000015) |
| Retinal ganglion cell loss and ganglion cell layer thinning | OCT in affected individuals showed significant ganglion cell layer thinning with electrophysiologic evidence of retinal ganglion cell dysfunction, indicating structural and functional vulnerability of RGCs in BBSOAS. | retinal ganglion cell axonogenesis; neuron projection development; visual system development | ganglion cell layer; retinal nerve fiber layer; axon | retinal ganglion cell | retina; retinal ganglion cell layer; optic nerve | (pqac-00000000, pqac-00000014, pqac-00000015) |
| Retinal ganglion cell axon guidance into optic stalk | Mouse Nr2f1 mutants showed disrupted retinal ganglion cell axonal guidance from neural retina into the optic stalk, providing a developmental explanation for optic nerve hypoplasia. | axon guidance; retinal ganglion cell axon guidance; optic nerve development | growth cone; axon; optic stalk region | retinal ganglion cell | neural retina; optic stalk; optic nerve | (pqac-00000000, pqac-00000014) |
| Extracortical visual pathway disorganization | Diffusion tensor imaging tractography in patients showed defective connections and disorganization of extracortical visual pathways, supporting cerebral visual pathway involvement beyond the optic nerve. | visual system development; axon tract development; forebrain neuron projection development | white matter; axon tract; myelinated axon | projection neuron | optic tract; lateral geniculate nucleus pathway region; visual pathway white matter | (pqac-00000000, pqac-00000014, pqac-00000018) |
| Oligodendrocyte/astrocyte imbalance in optic nerve | Nr2f1-deficient optic nerves developed an imbalance between oligodendrocytes and astrocytes, linked to postnatal hypomyelination and astrogliosis as a mechanism for optic nerve dysfunction. | glial cell differentiation; oligodendrocyte differentiation; astrocyte differentiation; central nervous system myelination | myelin sheath; optic nerve; glial cell projection | oligodendrocyte; astrocyte | optic nerve | (pqac-00000016) |
| Postnatal hypomyelination of optic nerve | Bertacchi et al. showed optic nerve hypomyelination in heterozygous mice, with slower optic axonal conduction velocity from retina to higher visual centers; early postnatal chemical treatment partially rescued myelination defects. | myelination; axon ensheathment in central nervous system; regulation of conduction | myelin sheath; node of Ranvier; axon | oligodendrocyte | optic nerve; visual pathway | (pqac-00000016) |
| Astrogliosis in optic neuropathy | Optic nerve pathology in the mouse model included astrogliosis, indicating reactive glial remodeling as part of tissue damage downstream of NR2F1 deficiency. | gliogenesis; astrocyte activation; response to nervous system injury | astrocyte projection; glial scar-related extracellular region | astrocyte | optic nerve | (pqac-00000016) |
| Reduced visual conduction and associative visual learning deficits | Adult heterozygous mice had slower optic axonal conduction velocity and associative visual learning deficits, linking structural optic nerve abnormalities to systems-level visual dysfunction. | visual learning; regulation of action potential propagation; sensory system development | axon; myelinated axon; visual cortex superficial layers | cortical neuron; retinal ganglion cell | optic nerve; visual cortex | (pqac-00000016) |
| Impaired hippocampal synaptic plasticity | Nr2f1+/- mice recapitulated neurological phenotypes and showed reduced long-term potentiation and long-term depression in hippocampal slices, suggesting a mechanism for intellectual disability and memory phenotypes. | synaptic plasticity; long-term synaptic potentiation; long-term synaptic depression; learning or memory | synapse; postsynaptic density; dendritic spine | pyramidal neuron; hippocampal neuron | hippocampus; dentate gyrus | (pqac-00000005, pqac-00000006, pqac-00000017) |
| Differential hippocampal gene expression with MMP upregulation | RNA-seq in adult Nr2f1+/- hippocampus revealed significant differential expression including upregulation of multiple matrix metalloproteases, implicating extracellular matrix remodeling in altered plasticity. | regulation of synaptic plasticity; extracellular matrix organization; proteolysis | extracellular matrix; synaptic cleft | hippocampal neuron | hippocampus | (pqac-00000005) |
| NR2F1 control of mitochondrial gene expression in neurons | Bonzano et al. identified nuclear-encoded mitochondrial genes as putative NR2F1 targets and found dysregulation of these genes in Nr2f1-heterozygous brains, supporting mitochondrial dysfunction in BBSOAS pathogenesis. | regulation of mitochondrial gene expression; mitochondrial organization; neuron development | mitochondrion; mitochondrial outer membrane; mitochondrial matrix | neuron; newborn neuron | brain; hippocampal dentate gyrus | (pqac-00000009) |
| Reduced mitochondrial mass and fragmentation in newborn neurons | Conditional NR2F1 loss in the adult hippocampal neurogenic niche caused reduced mitochondrial mass, mitochondrial fragmentation, and downregulation of key mitochondrial proteins in newborn neurons, impairing their survival and integration. | mitochondrial fission; mitochondrial organization; neuron differentiation; neuron survival; synapse organization | mitochondrion; mitochondrial network; neuronal soma | newborn neuron; neural stem cell | dentate gyrus; hippocampal neurogenic niche | (pqac-00000009) |


*Table: This table maps major disease mechanisms in Bosch-Boonstra-Schaaf optic atrophy syndrome to suggested GO, CL, and UBERON ontology terms. It is designed to support structured knowledge-base annotation of pathophysiology, affected cell types, and anatomical sites.*