Using the GFP-Fbn microfibril binding assay, we found that the GFP-Fbn constructs containing substitutions associated with either geleophysic dysplasia (Fig. 3, Panels D–F) or acromicric dysplasia (Fig. 3, Panels G–I) showed incorporation into the fibroblast-derived microfibril network to a similar level as that seen for wild-type GFP-Fbn. This evidence concerns the gene FBN1 and geleophysic dysplasia.