Overview
Macular telangiectasia type 2 (MacTel type 2) is a bilateral, slowly progressive macular disease characterized by telangiectatic capillaries in the parafoveal region, loss of Müller cells, and photoreceptor degeneration. It has a strong genetic component with heritability estimated at ~70%, linked to serine metabolism and glycine/serine pathway genes. MacTel affects approximately 1 in 1,000 adults and is increasingly recognized as a distinct neurodegenerative macular condition.
Genetics
Polygenic with strong contribution from serine metabolism genes. PHGDH, PSAT1, and PSPH variants affect serine biosynthesis. No single Mendelian gene identified.
| Gene | Locus | Inheritance | Notes |
|---|---|---|---|
| PHGDH | 1p12 | Complex | Phosphoglycerate dehydrogenase; serine biosynthesis |
| CPS1 | 2q35 | Complex | Carbamoyl phosphate synthetase 1; serine/glycine metabolism |
Clinical Presentation
Early
- Subtle visual distortion
- Parafoveal telangiectasia on FA
- Loss of foveal reflex
Progressive
- Reading difficulty
- Paracentral scotoma
- Crystalline deposits in retina
Advanced
- Subretinal neovascularization
- Significant central vision loss
- Outer retinal atrophy
Diagnosis
- OCT: Ellipsoid zone loss, hyporeflective cavities, outer retinal atrophy
- Fluorescein angiography: Parafoveal telangiectasia with late leakage
- FAF: Hyperautofluorescence at lesion margins
- Serine levels: Reduced serine in plasma (subset)
Current Research & Treatment
The MacTel Project (Lowy Medical Research Institute) is conducting a global natural history study and clinical trials. Oral serine supplementation (NCT03946085) showed significant benefit in slowing photoreceptor loss in a Phase 2/3 trial. Ciliary neurotrophic factor (CNTF) implant (NCT01949324) is also being studied.
Active Clinical Trials
The following active clinical trials are investigating treatments for Inherited Macular Telangiectasia (MacTel Type 2). Trial status and enrollment may change; always verify directly on ClinicalTrials.gov.