FBN2 and congenital contractural arachnodactyly: On the one hand, the deletion of exon 27 would disrupt the 17th cb-EGF domain of FBN2, affect the binding of the cb-EGF domain to calcium ions, and make fibrillin-2 more susceptible to hydrolysis; on the other hand, disruption of the 17th cb-EGF domain may alter the spatial conformation and intermolecular interactions of proteins (Xu et al. 2019), and eventually lead to CCA.