| Phenotype | HPO Term | HPO ID | Frequency | Onset | Phenotype Type |
|---|---|---|---|---|---|
| Severe visual impairment (LCA1) | Severe visual impairment | HP:0012378 | Very common; in one natural-history cohort 76% were severely visually impaired (hand movements or worse) (pqac-00000031); ~50% reported vision worse than counting fingers in review data (pqac-00000006) | Congenital/infancy | Symptom/functional deficit |
| Nystagmus (LCA1) | Nystagmus | HP:0000639 | Very common; reported in all patients in a 21-patient GUCY2D-LCA cohort (pqac-00000030) | Congenital/first 3 years | Clinical sign |
| Oculodigital sign / Franceschetti sign (LCA1) | Oculodigital sign | HP:0000658 | Common/characteristic; repeatedly reported in GUCY2D-LCA reviews and cohorts (pqac-00000003, pqac-00000006) | Infancy | Behavioral/clinical sign |
| Photophobia (LCA1) | Photophobia | HP:0000613 | Common/prominent in GUCY2D-LCA (pqac-00000002, pqac-00000006, pqac-00000020) | Infancy/early childhood | Symptom |
| Hyperopia (LCA1) | Hyperopia | HP:0000540 | Common; noted as a frequent refractive feature in GUCY2D-LCA/LCA reviews (pqac-00000020, pqac-00000033) | Childhood | Clinical finding/refractive abnormality |
| Absent or markedly diminished ERG (LCA1) | Abnormal electroretinogram | HP:0007703 | Very common; severe cone-rod dystrophy or severe photoreceptor dystrophy with undetectable or severely subnormal responses in most/all tested patients (pqac-00000028, pqac-00000030) | Congenital/infancy | Laboratory/functional abnormality |
| Preserved retinal structure despite severe dysfunction (LCA1) | Abnormality of the macula / preserved EZ with dysfunction* | HP:0007754* | Characteristic structural-functional dissociation; frequent in GUCY2D-LCA cohorts (pqac-00000005, pqac-00000028) | Childhood onward | Imaging/structural sign |
| Keratoconus (LCA1 complication) | Keratoconus | HP:0000563 | Uncommon but reported complication contributing to worse vision in some patients (pqac-00000030) | Later childhood/adolescence | Ocular complication |
| Early-onset cataract (LCA1 complication) | Juvenile cataract | HP:0000518 | Uncommon but reported in some GUCY2D-LCA patients as a cause of additional visual decline (pqac-00000030) | Childhood/adolescence | Ocular complication |
| Progressive vision loss (CORD6) | Progressive visual loss | HP:0000529 | Common/defining; adCORD shows progressive decline, with mean BCVA worsening ~0.022 logMAR/year (pqac-00000029) | Childhood/adolescence | Symptom/course feature |
| Color vision defects (CORD6) | Dyschromatopsia | HP:0000551 | Common; cone dysfunction and impaired color perception described across GUCY2D-CORD cohorts/kindreds (pqac-00000001, pqac-00000007) | Childhood/adolescence | Symptom |
| Photophobia (CORD6) | Photophobia | HP:0000613 | Common in cone-dominant disease and reported in affected families (pqac-00000001, pqac-00000007) | Childhood/adolescence | Symptom |
| Macular atrophy (CORD6) | Macular atrophy | HP:0007758 | Common in later disease; early granular macular changes progress to obvious macular atrophy (pqac-00000001, pqac-00000034) | Childhood/adolescence progressing in adulthood | Imaging/structural sign |
| Reduced cone responses / cone-rod dysfunction on ERG (CORD6) | Abnormal electroretinogram | HP:0007703 | Very common; reduced cone responses with relative rod preservation early, later rod involvement (pqac-00000001, pqac-00000007) | Childhood/adolescence | Laboratory/functional abnormality |
| Reduced visual acuity (CORD6) | Decreased visual acuity | HP:0007663 | Common; variable early, progressive over time, can reach severe visual impairment by mid-late adulthood (pqac-00000001, pqac-00000029, pqac-00000034) | Childhood/adolescence | Symptom/functional deficit |
| Central scotoma (CORD6) | Central scotoma | HP:0000611 | Reported in affected family members with GUCY2D-CORD (pqac-00000007) | Childhood/adolescence | Symptom |
| Peripheral retinal pigmentary changes (CORD6) | Retinal pigment epithelial mottling / pigmentary retinopathy* | HP:0001100* | Reported in some affected kindreds with generalized pigmentary granularity and peripheral bone-spicule-like changes (pqac-00000007) | Adolescence/adulthood | Fundus sign |
| Severe visual impairment/blindness by adulthood (CORD6) | Blindness / severe visual impairment | HP:0000618 | Substantial long-term risk; 32% probability of blindness or severe visual impairment by age 40 in one cohort (pqac-00000029) | Mid-adulthood after childhood/adolescent onset | Outcome/functional deficit |


*Table: This table summarizes major phenotypes reported across GUCY2D-related recessive retinopathy/LCA1 and dominant CORD6, with suggested HPO mappings, onset patterns, and qualitative frequency information. It is useful for disease knowledge base curation and phenotype annotation.*