- Written by: Sharalee Worms
FIS stands for Foal Immunodeficiency Syndrome - it is a recessive disease
FIS affects the immune system - foals appear normal when they are born but an inability to fight infections means they will die within three months or less or they are put down in reponse to their inability to fight infections
The condition is found in two rare related British pony breeds, the Fell and the Dales.
- Written by: Sharalee Worms
HERDA stands for Hereditary Equine Eegional Eermal Asthenia - it is a recessive disease 
Genetic Testing is Available
HERDA is horrific genetic disease which causes skin lesions and ulcerations, poor healing and scarring of wounds, and skin sloughing along the back of affected horses beginning around 1.5-2 years of age and progressively worsening over time. Most HERDA foals are euthanized as soon as they are diagnosed. There is no treatment. It is similar to WFFS (Warmblood Fragile Foal Syndrome which has symptoms which start earlier)
HERDA is found in quarter horses and breeds with QH influence (Paints, Appaoosas, etc.) IT is prevalent in the Cutting discipline. The carrier frequency is about 3.5% in Quarter Horses, with an incidence of over 25% in Cutting horses and has been traced back to Poco Bueno. It is one of the test required by all breeding stallions for the 5 panel of tests.
HERDA has been traced back to King, specifically through Poco Bueno.
- Written by: Sharalee Worms
HFH (known as Hydrocephalus, it is shortened to HFH for our purposes on this site)
HFH stands for Hydrocephalus in Friesian Horses - it s a recessive trait
HFH often results in stillbirths of affected foals and obstructed labor (dystocia) in dams, which can be fatal to the dam during birth. The condition is usually fatal and there is no effective treatment.
HFH is found in Friesian horses with as many as 15% of Friesian being carriers. It has been seen rarely in other breeds but it is not known at this time if it is caused by the same genetics.
- Written by: Sharalee Worms
HWSD stands for Hoof Wall Separation Disease - it is a recessive disease
Affected horses show separation and breaking of the dorsal hoof wall along the weight-bearing surface of the hoof during the first year of life. Horses are unable to carry their weight effectively and it often leads to laminitis and euthanasia. It does not affect all horses with the same severity. There is nottreatment that works long term for those that are strongly affected and putting them down is usually the only option.
This desease is found in Connemara ponies.
- Written by: Sharalee Worms
HYPP stands for Hyperkalemic periodic paralysis - it is a dominant disease Genetic Testing is Available
HYPP presents as sporadic episodes of muscle spasms, weakness, or paralysis in affected horses exposed to high potassium levels. Respiratory paralysis or heart failure may lead to death. Episodes may be triggered by stress, diet, lack of exercise, and recovery from anesthesia.
It has been traced to the QH stallion Impressive (althought their is some controversy that it might have gone back further than that). Treatment for episodes is usually done with Karo Syrup.
Homozygous HYPP horses (H/H) are often more symptomatic than n/H horses.
HYPP is one of the 5 panel fo tests required by all AQHA breeding stallions.