| Category | Finding | Details | Evidence |
|---|---|---|---|
| Disease name | Central areolar choroidal dystrophy | Rare hereditary macular dystrophy with bilateral, symmetrical, well-circumscribed loss of choroidal and retinal tissue causing progressive visual loss (pqac-00000000) | (pqac-00000000) |
| Identifier | OMIM | CACD cited as OMIM/MIM 215500 in disease/genetics literature (pqac-00000007, pqac-00000003) | (pqac-00000007, pqac-00000003) |
| Identifier | Phenotype-specific OMIM subtype | CACD phenotype within PRPH2-associated disease cited as OMIM #613105 in the 2024 PRPH2 cohort paper (pqac-00000009) | (pqac-00000009) |
| Synonyms/alternate labels | CACD; central areolar chorioretinal dystrophy | 2024 longitudinal PRPH2 cohort describes diffuse RPE atrophy “consistent with central areolar chorioretinal dystrophy (CACD)” (pqac-00000014) | (pqac-00000014) |
| Data source type | Aggregated disease-level resources and patient-level studies | Evidence here derives from systematic review/disease overviews plus family studies, multicenter cohorts, and longitudinal imaging/genetics studies rather than EHR-only sources (pqac-00000000, pqac-00000010, pqac-00000014) | (pqac-00000000, pqac-00000010, pqac-00000014) |
| Inheritance | Usually autosomal dominant; rare autosomal recessive cases reported | Reviews/testing summaries state CACD is mostly autosomal dominant, with rare recessive inheritance (pqac-00000000, pqac-00000007) | (pqac-00000000, pqac-00000007) |
| Key genes | PRPH2 | Main gene in most published CACD studies; PRPH2 variants are usually implicated in CACD and related macular dystrophies (pqac-00000001, pqac-00000002) | (pqac-00000001, pqac-00000002) |
| Key genes | GUCY2D | Reported CACD gene; example pathogenic missense variant p.Val933Ala / V933A in a Northern Irish family (pqac-00000001, pqac-00000007) | (pqac-00000001, pqac-00000007) |
| Key genes | GUCA1A | Included among CACD-implicated genes; variants such as p.Arg120Leu linked to severe maculopathy including CACD spectrum (pqac-00000002, pqac-00000004) | (pqac-00000002, pqac-00000004) |
| Key genes | CDHR1, ABCA4, TTLL5 | Listed in the 2022 systematic review/network analysis as additional CACD-implicated genes/candidates, though evidence strength varies and ABCA4 attribution was noted as needing validation (pqac-00000000, pqac-00000002) | (pqac-00000000, pqac-00000002) |
| Representative PRPH2 variants | Missense/splice variants linked to CACD | Arg195Leu, Arg172Trp, Arg203Pro, c.828+3A>T; Jeffery et al. note CACD reported with missense changes at codons Arg142, Arg172, Arg195, Ile196, Arg203, Gly208 (pqac-00000005, pqac-00000009, pqac-00000014) | (pqac-00000005, pqac-00000009, pqac-00000014) |
| Age at onset | Typical disease overview | Onset typically between the 3rd and 5th decades (pqac-00000000) | (pqac-00000000) |
| Age at onset | PRPH2 cohort | Median age at symptom onset across 241 PRPH2 patients was 40 years (range 4–78) (pqac-00000010) | (pqac-00000010) |
| Clinical course | Progressive | Disease progresses through early parafoveal RPE changes to well-demarcated atrophy and eventual foveal involvement with marked visual loss (pqac-00000000) | (pqac-00000000) |
| Staging | Four clinical stages | Stage 1 parafoveal RPE changes; stage 2 oval/round mildly atrophic hypopigmented area with speckled FAF; stage 3 well-demarcated RPE atrophy outside fovea; stage 4 foveal involvement with severe VA loss, commonly <20/200 (pqac-00000000) | (pqac-00000000) |
| Key clinical features | Macular/RPE/choriocapillaris atrophy | Bilateral central macular atrophy with RPE and choriocapillaris loss; pathology likely photoreceptor-first with secondary RPE/choriocapillaris involvement (pqac-00000000, pqac-00000004) | (pqac-00000000, pqac-00000004) |
| Imaging features | FAF | Speckled or stippled hyper-/hypoautofluorescence in earlier lesions; internal hypoautofluorescent patches in CACD-like areas (pqac-00000000, pqac-00000015) | (pqac-00000000, pqac-00000015) |
| Imaging features | OCT/OCTA | Outer retinal atrophy, central macular atrophy, intraretinal cystic spaces; OCTA can show choriocapillaris flow deficits beyond the clinically atrophic area (pqac-00000011) | (pqac-00000011) |
| Electrophysiology | ERG abnormalities | Full-field ERG in PRPH2 disease showed significantly reduced amplitudes across components and delayed light-adapted 30-Hz flicker and single-flash b-wave peak times (P < 0.001) (pqac-00000010) | (pqac-00000010) |
| Frequency within PRPH2 disease | CACD phenotype proportion | In the 241-patient PRPH2 cohort, FAF phenotypes included CACD in 28% (pqac-00000010) | (pqac-00000010) |
| Visual acuity statistic | PRPH2 cohort median VA | Median VA in the PRPH2 cohort was 0.18 logMAR in each eye (right-eye IQR 0–0.54; left-eye IQR 0–0.42) (pqac-00000010) | (pqac-00000010) |
| Natural history/genotype–phenotype | c.828+3A>T vs L185P PRPH2 | c.828+3A>T presented in the 5th decade with diffuse RPE atrophy/CACD and progressed to extensive atrophy in the 6th–8th decades; L185P had milder PD/AVMD phenotypes with later central atrophy and better VA (pqac-00000014) | (pqac-00000014) |
| Genetic diagnostic yield | Solved cases in one CACD cohort | One cited CACD series solved 7 of 20 cases genetically (35%), highlighting incomplete yield (pqac-00000001) | (pqac-00000001) |
| Relative rarity | Observation within IRD cohorts | Another cited study found CACD in 0.92% of 2,158 individuals in an IRD context (pqac-00000001) | (pqac-00000001) |
| Prevalence estimate | Reported overall prevalence | Genetic-testing review reported overall prevalence as 1–9 per 100,000, but this estimate comes from an older testing-focused summary and should be treated cautiously (pqac-00000007) | (pqac-00000007) |
| Differential diagnosis | AMD/geographic atrophy phenocopy | Some PRPH2/CACD cases were initially misdiagnosed as geographic atrophy secondary to AMD; multimodal imaging and sequencing improve distinction (pqac-00000003, pqac-00000011, pqac-00000014) | (pqac-00000003, pqac-00000011, pqac-00000014) |
| Treatment status | No established disease-modifying therapy | Reviews state no effective treatment currently prevents CACD progression; management is mainly diagnostic monitoring and inherited retinal disease supportive care (pqac-00000000) | (pqac-00000000) |


*Table: This table summarizes core disease-level facts for Central Areolar Choroidal Dystrophy supported by the evidence gathered in this conversation. It includes identifiers, synonyms, inheritance, genes, hallmark phenotypes, and key quantitative findings useful for knowledge-base curation.*