What are the genetic changes related to ophthalmo-acromelic syndrome ?
Mutations in the SMOC1 gene cause ophthalmo-acromelic syndrome. The SMOC1 gene provides instructions for making a protein called secreted modular calcium-binding protein 1 (SMOC-1). This protein is found in basement membranes, which are thin, sheet-like structures that support cells in many tissues and help anchor cells to one another during embryonic development. The SMOC-1 protein attaches (binds) to many different proteins and is thought to regulate molecules called growth factors that stimulate the growth and development of tissues throughout the body. These growth factors play important roles in skeletal formation, normal shaping (patterning) of the limbs, as well as eye formation and development. The SMOC-1 protein also likely promotes the maturation (differentiation) of cells that build bones, called osteoblasts.  SMOC1 gene mutations often result in a nonfunctional SMOC-1 protein. The loss of SMOC-1 could disrupt growth factor signaling, which would impair the normal development of the skeleton, limbs, and eyes. These changes likely underlie the anophthalmia and skeletal malformations of ophthalmo-acromelic syndrome. It is unclear how SMOC1 gene mutations lead to the other features of this condition.  Some people with ophthalmo-acromelic syndrome do not have an identified mutation in the SMOC1 gene. The cause of the condition in these individuals is unknown.