These data and those from other laboratories showing that vitamin K supplementation does not increase the level of circulating carboxylated MGP in a case of Keutel syndrome (MGP mutations; Cranenburg et al., 2011) seem to indicate that MGP carboxylation is under a complex control, only partly dependent on vitamin K, in agreement with recent results obtained on PXE fibroblasts treated in vitro with vitamin K supplementation (Boraldi et al., in press). The gene discussed is MGP; the disease is Keutel syndrome.