Fasting plasma GLP-1 levels were comparable between CTX patients and controls (2.3 ± 1.1 vs. 3.5 ± 3.5 pmol/L, p = 0.41) but were higher at time points 60 and 240 min in CTX patients (Figure 4D). The gene discussed is GCG; the disease is cerebrotendinous xanthomatosis.