| Phenotype | Frequency / quantitative data | Age / onset notes | Progression notes | Source type | Suggested HPO term |
|---|---:|---|---|---|---|
| Developmental delay | 88% overall; DBD-group 33/36 (91.67%) vs non-DBD-group 52/64 (81.25%) (pqac-00000004, pqac-00000002) | Usually evident in infancy/early childhood through delayed milestones (walking, first words) (pqac-00000011, pqac-00000013) | Chronic neurodevelopmental phenotype; not described as remitting (pqac-00000011) | Review + case-based genotype-phenotype comparison | HP:0001263 |
| Intellectual disability | 85.9% overall (pqac-00000004) | Typically recognized in childhood after developmental concerns; severity ranges mild to severe (pqac-00000009, pqac-00000011) | Persistent; variable expressivity (pqac-00000011) | Review | HP:0001249 |
| Optic atrophy / optic nerve impairment | Optic atrophy 66.3% overall; optic nerve impairment 31/36 (86.11%) vs 48/64 (75.00%) by genotype groups (pqac-00000004, pqac-00000002) | Visual abnormality often apparent in early childhood; may be suspected in infancy with poor eye tracking (pqac-00000014, pqac-00000013) | Visual loss in BBSOAS appears largely non-progressive in available longitudinal ophthalmic follow-up, although classic OA is generally degenerative; BBSOAS includes developmental ONH/OA overlap (pqac-00000014, pqac-00000013) | Review + case series + genotype-phenotype comparison | HP:0000648 |
| Optic nerve hypoplasia / small hypoplastic optic nerves | Small and/or tilted hypoplastic optic nerves in 10/22 individuals (pqac-00000000, pqac-00000014) | Early childhood / congenital developmental ocular phenotype (pqac-00000014, pqac-00000013) | Congenital, generally non-progressive developmental defect (pqac-00000013, pqac-00000014) | Case series | HP:0008058 |
| Visual impairment / reduced visual acuity | Vision impairment 27/36 (75.00%) vs 53/64 (82.81%); low visual acuity described as common (pqac-00000002, pqac-00000011) | Becomes apparent in early childhood; infancy may show poor eye tracking (pqac-00000014, pqac-00000013) | “No significant deterioration” over follow-up in available longitudinal data; stable non-progressive reduction in visual acuity reported (pqac-00000014, pqac-00000011) | Case series + review + genotype-phenotype comparison | HP:0000505 |
| Cortical visual impairment | 44.6% overall (pqac-00000004) | Usually recognized in infancy/childhood during neuro-ophthalmic assessment (pqac-00000011, pqac-00000013) | Often treated clinically as a developmental visual-processing deficit; progression not clearly established (pqac-00000013) | Review | HP:0100704 |
| Epilepsy / seizures | 46.7% overall; DBD-group 24/36 (66.67%) vs non-DBD-group 22/64 (34.38%), p=0.002 (pqac-00000004, pqac-00000002) | Can present in infancy, including infantile spasms, or later childhood (pqac-00000011, pqac-00000003) | Variable course; chronic seizure disorder when present (pqac-00000011) | Review + genotype-phenotype comparison | HP:0001250 |
| Autism spectrum disorder / autistic traits | ASD 39.1% overall and autistic traits 14.1%; DBD-group ASD 22/36 (61.11%) vs non-DBD-group 23/64 (35.94%), p=0.015 (pqac-00000004, pqac-00000002) | Usually recognized in childhood during behavioral/developmental assessment (pqac-00000011) | Persistent neurobehavioral phenotype; variable severity (pqac-00000011) | Review + genotype-phenotype comparison | HP:0000729 |
| Hypotonia | 62% overall (pqac-00000004) | Often among earliest infantile findings (pqac-00000011, pqac-00000013) | May persist and contribute to motor delay; course variably described (pqac-00000011) | Review | HP:0001252 |
| Hearing impairment | 11% overall (pqac-00000004) | Childhood recognition; periodic hearing evaluation recommended in care pathways (pqac-00000011, pqac-00000013) | Progression not established from retrieved evidence (pqac-00000013) | Review | HP:0000365 |
| Abnormal corpus callosum | DBD-group 16/36 (44.44%) vs non-DBD-group 16/64 (25.00%), p=0.045 (pqac-00000002) | Developmental brain malformation detectable on MRI, usually identified in childhood workup (pqac-00000002, pqac-00000011) | Structural/developmental; not a progressive lesion per se (pqac-00000002) | Genotype-phenotype comparison | HP:0001273 |
| Retinal ganglion cell loss / ganglion cell layer thinning | Qualitative but significant OCT/electrophysiologic evidence of RGC loss and ganglion cell layer thinning in the 22-person cohort (pqac-00000000, pqac-00000014) | Developmental ocular defect evident with detailed ophthalmic testing in childhood (pqac-00000014) | Supports congenital, largely non-progressive visual deficit in available follow-up (pqac-00000014) | Case series | HP:0030639 |


*Table: This table summarizes phenotype frequencies, onset patterns, and progression notes for Bosch–Boonstra–Schaaf optic atrophy syndrome using the retrieved review, case-series, and genotype–phenotype comparison evidence. It is useful for rapid knowledge-base extraction of common manifestations and associated HPO terms.*