On the other hand, as mentioned, Figueiredo et al. [36] showed that serum total calcium and PTH were statistically significantly lower in MEN2 than MEN1, of 10.6 10.6 ± 1.1 versus 11.7 ± 1.2 mg/dL (p = 0.03) and 108 versus 196.9 pg/mL (p = 0.01), respectively, but, also, than found in hyperparathyroidism-jaw tumor syndrome, of 12.9 ± 1.8 mg/dL (p < 0.001) and 383.5 pg/mL (p = 0.01) [36], respectively. Here, MEN1 is linked to hyperparathyroidism.