Understanding Lethal White Overo Syndrome in Horses

Lethal White Overo Syndrome (LWOS) is a serious genetic disorder that affects horses, particularly those with the Overo coat pattern. The condition is caused by mutations in the EDNRB gene, which plays a crucial role in the development of the enteric nervous system. Foals affected by LWOS typically present with severe intestinal malformations, leading to colonic atresia and resulting in non-viability shortly after birth. This condition is inherited in an autosomal recessive manner, meaning that both parents must carry the gene variant for an offspring to be affected. DNA testing is essential for identifying carriers of the LWOS mutation, allowing breeders to make informed decisions to minimize the risk of producing affected foals. By screening breeding stock, veterinarians and breeders can work together to ensure healthier outcomes in future generations. Understanding the genetic basis of LWOS is vital for responsible breeding practices in the equine community.