Warmblood Fragile Foal Syndrome (WFFS) is a genetic disorder seen in horses. It is an autosomal recessive disorder, which means that both the sire and dam must be carriers for a foal to be affected. Foals with WFFS are naturally aborted, stillborn, or euthanized. WFFS is a genetic defect of connective tissue and foals born with it have hyper-extendible, abnormally thin, fragile skin that rips easily. It is associated with mutations in the gene coding for Lysyl hydroxylase 1 that result in a non-functional enzyme. The syndrome is characterized by soft tissue abnormalities that display in the form of extremely fragile and friable skin, lax and hyper-extensible limb tendons, and ruptured internal organs. Horses that are heterozygous for WFFS are phenotypically normal, so genetic testing is necessary to prevent breeding carriers. A genetic test for WFFS was made commercially available in 2013. Approximately 9-11% of Warmblood horses are carriers, with lower carrier frequencies in Thoroughbreds and Knabstruppers.