Overview
North Carolina macular dystrophy (NCMD) is an autosomal dominant non-progressive macular dystrophy caused by regulatory mutations near PRDM13 or IRXB gene clusters on chromosome 6q. Despite its name, it is found worldwide. It is characterized by drusen-like macular deposits or macular coloboma-like lesions present from birth, with visual acuity ranging from normal to severely reduced depending on severity. Importantly, the condition is congenital and stationary — it does not progress after childhood.
Genetics
Caused by non-coding regulatory mutations affecting PRDM13 expression. Two loci identified: MCDR1 (6q16) and MCDR3 (5p15). Inheritance is autosomal dominant.
| Gene | Locus | Inheritance | Notes |
|---|---|---|---|
| PRDM13 (regulatory) | 6q16.1 | AD | Non-coding duplications/SNVs near PRDM13; MCDR1 locus |
| IRXB cluster (regulatory) | 16q12.1 | AD | Non-coding variants near IRX1/IRX2; MCDR3 locus |
Clinical Presentation
Congenital (stationary)
- Macular drusen or coloboma-like lesion present from birth
- Visual acuity 20/20 to 20/200 depending on grade
- No progression after childhood
Grade I–III
- Grade I: Drusen only, near-normal vision
- Grade II: Confluent drusen/exudative changes
- Grade III: Macular coloboma, severely reduced acuity
Diagnosis
- Fundus: Characteristic macular drusen or coloboma-like lesion
- OCT: Structural changes at fovea
- ERG: Normal (distinguishes from progressive dystrophies)
- Genetic testing: Chromosomal microarray and sequencing of MCDR1/MCDR3 loci
Current Research & Treatment
No treatment is required or available for NCMD as it is stationary. Genetic counseling is important given the autosomal dominant inheritance. Research focuses on understanding the regulatory mechanisms of PRDM13 in macular development.
Active Clinical Trials
The following active clinical trials are investigating treatments for North Carolina Macular Dystrophy. Trial status and enrollment may change; always verify directly on ClinicalTrials.gov.