What are the genetic changes related to acromicric dysplasia ?
Acromicric dysplasia is caused by mutations in the FBN1 gene, which provides instructions for making a large protein called fibrillin-1. This protein is transported out of cells into the extracellular matrix, which is an intricate lattice of proteins and other molecules that forms in the spaces between cells. In this matrix, molecules of fibrillin-1 attach (bind) to each other and to other proteins to form threadlike filaments called microfibrils. The microfibrils become part of the fibers that provide strength and flexibility to connective tissues, which support the bones, skin, and other tissues and organs. Additionally, microfibrils store molecules called growth factors, including transforming growth factor beta (TGF-), and release them at various times to control the growth and repair of tissues and organs throughout the body.  Most of the FBN1 gene mutations that cause acromicric dysplasia change single protein building blocks in the fibrillin-1 protein. The mutations result in a reduction and disorganization of the microfibrils. Without enough normal microfibrils to store TGF-, the growth factor is abnormally active. These effects likely contribute to the physical abnormalities that occur in acromicric dysplasia, but the mechanisms are unclear.