Two patients (II-2 and II-5) with RET p.S891A/p.R525W presented with MTC, whereas three carriers with p.R525W (II-4, III-9, and III-12) had no evidence of thyroid/skin or bCt/sCt abnormalities (Figure 1 and Table 1). This evidence concerns the gene RET and medullary thyroid gland carcinoma.