['To investigate, in a large cohort of 2494 individuals with diabetes mellitus, whether functional single nucleotide polymorphisms in the promoter region of tumour necrosis factor (TNF) and lymphotoxin-alpha (LTA) genes are associated with type of diabetes or presence of diabetic retinopathy.', 'A total of 334 type 1 diabetes and 999 type 2 diabetes participants with sight-threatening diabetic retinopathy, and 260 type 1 diabetes and 901 type 2 diabetes participants with no diabetic retinopathy or minimal non-proliferative diabetic retinopathy, were genotyped for two single nucleotide polymorphisms (rs1800629 and rs361525).', 'The A allele of rs1800629 was associated with type 1 diabetes (p < 0.001; odds ratio = 0.62). After adjustment for age, sex, diabetes duration, HbA1c, hypertension and nephropathy, no significant association was found between rs1800629 or rs361525 and sight-threatening diabetic retinopathy.'] Is promoter polymorphism at the tumour necrosis factor/lymphotoxin-alpha locus associated with type of diabetes but not with susceptibility to sight-threatening diabetic retinopathy?