A germline missense mutation (c.1016C>T) was identified in TTF-1/NKX2.1 that led to a mutant TTF-1 protein (p.Ala339Val) in 4 of the 20 MNG/PTC patients (20%) after the targeted DNA sequencing of 20 PTC patients with a history of MNG, 284 PTC patients without a history of MNG and 349 healthy controls (24). This evidence concerns the gene NKX2-1 and toxic multinodular goitre.