Cone-Rod Dystrophy

Overview

Cone-rod dystrophy (CRD) is a group of inherited retinal dystrophies in which cone photoreceptors are affected first, followed by rod degeneration — the reverse of retinitis pigmentosa. CRD presents with early central vision loss, color vision defects, and photophobia, followed by progressive peripheral field loss and night blindness. It is genetically heterogeneous with multiple inheritance patterns.

Genetics

CRD is genetically heterogeneous with mutations in 30+ genes. ABCA4 mutations (typically causing Stargardt disease) can also cause CRD. GUCY2D, CRX, and RPGR are among the most common.

Clinical Presentation

Diagnosis

• ERG: Cone responses more severely reduced than rod responses (distinguishes from RP)
• Color vision testing: Acquired color vision defects
• Visual field: Central scotoma progressing to peripheral loss
• OCT: Foveal/macular photoreceptor loss
• Fundus: Macular atrophy, bull's-eye pattern in some
• Genetic testing: CRD gene panel (30+ genes)

Current Research & Treatment

Therapeutic development for CRD follows similar strategies to RP and Stargardt disease. Gene therapy for GUCY2D-associated CRD is in clinical trials. ABCA4-targeted therapies (gene augmentation, antisense oligonucleotides) are relevant for ABCA4-CRD. Neuroprotective approaches and optogenetics are being explored for advanced disease.

Active Clinical Trials

The following active clinical trials are investigating treatments for Cone-Rod Dystrophy. Trial status and enrollment may change; always verify directly on ClinicalTrials.gov.

Supporting Organizations

The following nonprofit organizations fund research, support patients, and advocate for advances in the treatment and cure of Cone-Rod Dystrophy.