FBN1 and connective tissue disorder: This study was motivated by two other recent studies that suggested FBN1 alterations in DS (Vilardell et al., 2011; Pasmatzi et al., 2006; Vis et al., 2009b) which is usually downregulated in MFS, MFS-like (Gao et al., 2010) and in other connective tissues disorders like Williams–Beuren syndrome (Henrichsen et al., 2011).