Together with the National Stud in Avenches and the Franches-Montagnes breeding association we identified the causative gene for this lethal hereditary disease. The research data enabled the development of an indirect marker test. This test predicts the genotype of a horse with >98% accuracy. The Franches-Montagnes breeding association runs a successful breeding program towards the eradication of this defect. No affected foal has been born for several years.