"Warmblood" Fragile Foal Syndrome (ffs)
Gene or Region: PLOD1
Reference Variant: C
Mutant Variant: T
Affected Breeds: Warmblood and Other Breeds
Research Confidence: High - Findings reproduced multiple studies
Explanation of Results: ffs/ffs = homozygous for Fragile Foal Syndrome, trait expressed ffs/N = heterozygous for Fragile Foal Syndrome, carrier N/N = no variant detected
Warmblood Fragile Foal Syndrome: Genetic Testing and Health Insights for Horse Breeders
Fragile Foal Syndrome is a connective tissue disorder resulting in joint laxity and extremely thin skin that is only loosely connected to the body. The skin is easily torn, resulting in lacerations, hematomas, and seromas across the foal. Affected foals are euthanized shortly after birth. As Fragile Foal Syndrome is a recessive disorder, horses must inherit two copies (ffs/ffs) to show the disease. Horses with only one allele (ffs/N) are known as carriers due to their ability to produce affected offspring.
Gene Information
PLOD1 is an enzyme involved in collagen synthesis. Mutations in mice and humans result in similar connective tissue disorders. The mutation observed in horses alters an amino acid, likely disrupting the function of the encoded protein.
References
Monthoux C et al., “Skin malformations in a neonatal foal tested homozygous positive for Warmblood Fragile Foal Syndrome.” (2015) BMC Vet Res. 11: 12. PMID: 256373371.
More Horse Health
Hereditary Equine Regional Dermal Asthenia
Hereditary Equine Regional Dermal Asthenia (HERDA) is a degenerative skin disease that primarily affects the American Quarter Horse. Loose skin is often an early indication of the disease, and severe seromas, hematomas, ulcerations usually develop around 1.5 years of age. There is no cure, and the majority of affected animals have to be euthanized within 2-4 years.
Hydrocephalus
Hydrocephalus (HDC) is an abnormal build up of cerebral spinal fluid around the brain. It is believed that a narrowed passage within the brain prevents normal fluid absorption, leading to an obvious external cranial distension. Affected foals are often stillborn and are associated with dystocia in the dams.