Fetal Overgrowth Syndrome Markers Discovered

Coletta Hargis BWS
A child with BWS, showing the enlarged tongue characteristic of the disorder.

Both humans and cattle share a similar epigenetic fetal overgrowth disorder that occurs more frequently after assisted reproduction procedures.  This disorder is called Beckwith-Widemann syndrome (BWS) in humans, and Large Offspring syndrome (LOS).  In both humans and cattle, it can result in the overgrowth of fetuses and enlarged babies.  While rare, this naturally occurring syndrome can cause physical abnormalities, and often result in both the deaths of both babies and mothers.  Recently, however, researchers at the University of Missouri have identified a number of genes that contribute to LOS in cattle.  According to Rocío Melissa Rivera, an associate professor in the MU College of Agriculture, Food and Natural Resources, identifying these genes in cattle will help to identify genes that cause BWS in humans.

Both physically and molecularly, BWS and LOS have a lot in common with each other.  According to Rivera, by identifying LOS genes, researchers can take steps toward discovering which genes cause BWS in humans.  Since these disorders have been associated with pregnancies from in vitro, knowing which genes cause these disorders will allow doctors to choose embryos for implantation that don’t have the molecular markers for BWS.  BWS results in babies that grow and gain weight at an abnormal rate in both the womb and early childhood.  Many children suffering from BWS have enlarged tongues, abdominal wall defects, suffer from asymmetric growth and are at a higher risk for cancer.  However, apart from the most severe cases, BWS isn’t fatal to humans unless they develop undetected cancer from it.

LOS in cattle has many characteristics similar to BWS, including rapid growth, weight gain in the womb, large tongues and abdominal wall defects.  Unlike BWS, however, LOS is often much more deadly, since many calves can die within a week of birth due to an inability to support their own weight and size.  Since in vitro is common in cattle breeding, LOS is a potential problem for many breeders.  This means that it’s particularly important for breeders to be able to identify the genetic causes of LOS, so that they can avoid impregnating their cattle with embryos predisposed to the disorder.  Overall, this will allow the breeding process to be much more efficient and safe.