Overgrowth Syndrome

Vet Clin North Am Food Anim Pract. 2019 Jul;35(2):265-276. doi: 10.1016/j.cvfa.2019.02.007.


Large offspring syndrome (LOS) is a fetal overgrowth condition in bovines most often observed in offspring conceived with the use of assisted reproductive technologies (ART). Phenotypes observed in LOS include, overgrowth, enlarged tongues, umbilical hernias, muscle and skeleton malformations, abnormal organ growth and placental development. Although LOS cases have only been reported to be associated with ART, fetal overgrowth can occur spontaneously in cattle (S-LOS). S-LOS refers to oversized calves that are born at normal gestation lengths. ART-induced LOS has been characterized as an epigenetic syndrome, more specifically, a loss-of-imprinting condition. We propose that S-LOS is also a loss-of-imprinting condition.

Keywords: Abnormal offspring syndrome; Assisted reproduction; Large offspring syndrome; Overgrowth; Spontaneous LOS.

Publication types

  • Case Reports
  • Review

MeSH terms

  • Animals
  • Beckwith-Wiedemann Syndrome / genetics
  • Beckwith-Wiedemann Syndrome / pathology
  • Beckwith-Wiedemann Syndrome / veterinary
  • Cattle
  • Cattle Diseases / etiology
  • Cattle Diseases / genetics
  • Cattle Diseases / pathology*
  • Female
  • Growth Disorders / genetics
  • Growth Disorders / pathology
  • Growth Disorders / veterinary*
  • Humans
  • Pregnancy
  • Reproductive Techniques, Assisted / adverse effects
  • Reproductive Techniques, Assisted / veterinary*