SMAD3 and Loeys-Dietz syndrome: Indeed, MFS shares cardiovascular and skeletal features with related conditions, notably Loeys-Dietz syndromes (LDS) that are linked to pathogenic variants of genes encoding components of the TGFβ signaling pathway, notably transforming growth factor beta-receptors 1 and 2 (TGFβR1 and TGFβR2) and mothers against decapentaplegic homolog 3 (SMAD3) [4].