What are the genetic changes related to Stve-Wiedemann syndrome ?
Stve-Wiedemann syndrome is usually caused by mutations in the LIFR gene. This gene provides instructions for making a protein called leukemia inhibitory factor receptor (LIFR). Receptor proteins have specific sites into which certain other proteins, called ligands, fit like keys into locks. Together, ligands and their receptors trigger signals that affect cell development and function.  The LIFR protein acts as a receptor for a ligand known as leukemia inhibitory factor (LIF). LIFR signaling can control several cellular processes, including growth and division (proliferation), maturation (differentiation), and survival. First found to be important in blocking (inhibiting) growth of blood cancer (leukemia) cells, this signaling is also involved in the formation of bone and the development of nerve cells. It appears to play an important role in normal development and functioning of the autonomic nervous system.  Most LIFR gene mutations that cause Stve-Wiedemann syndrome prevent production of any LIFR protein. Other mutations lead to production of an altered protein that likely cannot function. Without functional LIFR, signaling is impaired. The lack of LIFR signaling disrupts normal bone formation, leading to osteopenia, bowed legs, and other skeletal problems common in Stve-Wiedemann syndrome. In addition, development of nerve cells, particularly those involved in the autonomic nervous system, is abnormal, leading to the problems with breathing, feeding, and regulating body temperature characteristic of this condition.  A small number of people with Stve-Wiedemann syndrome do not have an identified mutation in the LIFR gene. Researchers suggest that other genes that have not been identified may be involved in this condition.