FBN1 and Severe short stature: In addition, some genes, such as Fibrillin-1 (FBN1), have been associated with both overgrowth and dwarfism, depending on the kinds of changes that occurred on them; mutations in this gene have been described in Marfan syndrome, which is characterized by tall stature and arachnodactyly, whereas the TB5 mutations in this gene were responsible for short stature phenotypes.