Genome-wide analyses identify common variants associated with macular telangiectasia type 2

Idiopathic juxtafoveal retinal telangiectasis type 2 (macular telangiectasia type 2; MacTel) is a rare neurovascular degenerative retinal disease. To identify genetic susceptibility loci for MacTel, we performed a genome-wide association study (GWAS) with 476 cases and 1,733 controls of European ancestry. Genome-wide significant associations (P < 5 × 10−8) were identified at three independent loci (rs73171800 at 5q14.3, P = 7.74 × 10−17; rs715 at 2q34, P = 9.97 × 10−14; rs477992 at 1p12, P = 2.60 × 10−12) and then replicated (P < 0.01) in an independent cohort of 172 cases and 1,134 controls. The 5q14.3 locus is known to associate with variation in retinal vascular diameter, and the 2q34 and 1p12 loci have been implicated in the glycine/serine metabolic pathway. We subsequently found significant differences in blood serum levels of glycine (P = 4.04 × 10−6) and serine (P = 2.48 × 10−4) between MacTel cases and controls

Carotid stiffness is associated with retinal microvascular dysfunction—The Maastricht study

OBJECTIVE: This study investigated whether arterial stiffening is a determinant of subtle retinal microvascular changes that precede diabetic retinopathy. RESEARCH DESIGN AND METHODS: This study used cross‐sectional data from the Maastricht Study, a type 2 diabetes‐enriched population‐based cohort study. We used multivariable linear regression analysis to investigate, in individuals without and with type 2 diabetes, the associations of carotid distensibility coefficient and carotid‐femoral pulse wave velocity with retinal microvascular diameters and flicker light‐induced dilation and adjusted for cardiovascular and lifestyle risk factors. RESULTS: The retinal microvascular diameter study population consisted of N = 2434 participants (51.4% men, mean ± SD age 59.8 ± 8.1 years, and 28.1% type 2 diabetes). No measures of arterial stiffness were significantly associated with microvascular diameters. Greater carotid distensibility coefficient (i.e., lower carotid stiffness) was significantly associated with greater retinal arteriolar flicker light‐induced dilation (per standard deviation, standardized beta [95% CI] 0.06 [0.00; 0.12]) and non‐significantly, but directionally similarly, associated with greater retinal venular flicker light‐induced dilation (0.04 [−0.02; 0.10]). Carotid‐femoral pulse wave velocity (i.e., aortic stiffness) was not associated with retinal microvascular flicker light‐induced dilation. The associations between carotid distensibility coefficient and retinal arteriolar and venular flicker light‐induced dilation were two‐ to threefold stronger in individuals with type 2 diabetes than in those without. CONCLUSION: In this population‐based study greater carotid, but not aortic, stiffness was associated with worse retinal flicker light‐induced dilation and this association was stronger in individuals with type 2 diabetes. Hence, carotid stiffness may be a determinant of retinal microvascular dysfunction