NSE had increased odds of repeating at least one level during levels 3–6 of the programme when compared to either GE students (OR 2.74, 95% CI 1.21, 6.21, P = 0.016) or SLE (OR 4.10, 95% CI 1.93, 8.70, P < 0.001). This evidence concerns the gene ENO2 and systemic lupus erythematosus.