Guide to Birth Defects & Diseases in Fluffy Foals (BeattieBellman)

FluffMed Qwik-Guide: Congenital Defects & Inherited Disorders in Fluffy Ponies

FluffMed is a publication of the Fluffy Industry Association of America(FIAA). Copyright © 20XX

As any seasoned fluffy breeder will tell you, the birth of a litter is one of the most joyous occasions in life for mare and owner alike. Few things are as adorable (and moreover, marketable) as the sight of a half-dozen colorful “chirpy babbehs”, only a few hours old, all peeping happily as their mother feeds & snuggles them. The cuteness of these little bundles of joy holds an enduring appeal that has helped the industry sell units even in an atmosphere of general negativity towards fluffies.

However, not every foal enters the world as the perfect image of a lovable children’s biotoy. Birth defects & disorders are an unfortunate fact of life for fluffy breeders - a price we pay for the imperfect genetics of the original Hasbio prototypes that were released into the wild. Fortunately, there are a number of steps that commercial breeders can take to reduce the occurrence of these abnormalities in their stock.

The FIAA emphasizes that all breeders & mill operators should keep detailed records for their selective breeding program; this will help identify mares/stallions who carry the traits for hereditary defects, allowing them to be culled out of the gene pool. The use of industry standard feeds & nutritional supplements, climate-controlled habitats, and synthetic hormones is also strongly recommended to keep pregnant dams happy & healthy during the gestational period.

Listed below are some of the more common congenital defects and inherited disorders that commercial breeders may encounter in fluffy foals:

  • Uroperitoneum
  • Neonatal Encephalopathy (“dummy foal”)
  • Pyloric Stenosis
  • Trisomy 62 (sensitive baby syndrome)
  • Junctional Epidermolysis Bullosa
  • Lethal White Syndrome
  • Cerebellar Abiotrophy


Uroperitoneum refers to a defect in the urinary system that allows urine to leak into the abdominal cavity. It can develop during labor, where the impact of uterine contractions on the fetal foal can result in tearing of the bladder. Colts are twice as likely to be affected as fillies. There is evidence that some fluffies may be genetically predisposed to a weakened bladder wall, increasing the risk for uroperitoneum.

Foals with uroperitoneum will initially appear normal, but gradually sicken 24 to 72 hours after birth. An afflicted foal may be observed frequently straining to urinate but producing little or no output. The abdomen will become bloated and distended as the condition progresses, causing severe pain. Ineffective removal of urine will lead to toxic levels of urea, creatinine, and electrolytes accumulating in the bloodstream. Left untreated, the foal will die within a week from peritonitis, acute renal failure, or (rarely) abdominal rupture.

Surgery is required to correct the defect, and is generally performed 10-15 days after birth. The foal can be stabilized in the meantime by placement of a peritoneal drainage catheter as well as infusions of sodium bicarbonate/dextrose solution to correct electrolyte imbalances. Extreme caution is required during this period to avoid infection. Survival rate with treatment is about 70%.

Due to the expense of treatment, the FIAA recommends that breeders euthanize any foals with uroperitoneum unless they hold considerable economic value (e.g. alicorns).

Neonatal Encephalopathy (dummy foal)

Neonatal encephalopathy is a form of brain damage caused by oxygen deprivation before or during birth. Hypoxic brain injury can occur due to placental insufficiency, anemia, hormone imbalances, or premature umbilical detachment. The risk is higher if the mare is stressed during the delivery. Newborn foals may suffer further damage from reperfusion injury after birth.

“Dummy foals” will appear lethargic, struggle to find a teat or suckle, and show little affection for the mare. Vocalizations are abnormal - a “grunting” or “barking” sound is frequently reported, as opposed to the usual chirping. The eyes remain closed as the foal grows, and the tongue will protrude out of the mouth due to poor muscle tone. Other neurological symptoms include blindness, dysphagia, ataxia, seizures, and catalepsy.

The brain damage caused by NE is generally irreversible. Treatment consists of supportive measures such as anticonvulsants, IV glucose, and nasogastric feeding. Fluffies with this disease do not develop normally and will be unable to walk or speak. They require considerable time & effort to keep alive, and even under ideal conditions will usually die in 4-8 months. For this reason, the FIAA recommends euthanasia in all cases.

Pyloric Stenosis

Pyloric stenosis is a narrowing of the pyloric sphincter, the opening that connects the stomach to the small intestine. In fluffies, this is usually caused by congenital hypertrophy of the smooth muscles of the sphincter. The hypertrophic pylorus obstructs the flow of gastric contents, resulting in malnutrition and damage to the GI tract.

Newborn foals afflicted with pyloric stenosis will frequently spit up milk and cry constantly. As they grow, they will be underweight compared to their siblings, often struggling to transition from milk to solid food. Adult fluffies with untreated pyloric stenosis appear sickly and suffer from colic & gastric ulcers. Severe cases can lead to dehydration, which may be fatal if not corrected quickly.

Mild cases can be managed with a specialized diet and oral atropine drops, while more serious cases require surgery. If treated correctly, foals with pyloric stenosis have a 95% survival rate and will live as long as any other fluffy. However, breeders may find it difficult to find a buyer for these special-needs biotoys; an FIAA-accredited broker should be contacted for assistance with making a sale.

Trisomy 62 (sensitive baby syndrome)

Trisomy 62, popularly known as Sensitive Baby Syndrome or SBS, is a complex genetic disorder caused by the formation of an extra copy of chromosome 62 during fertilization. The presence of this additional chromosome causes certain genes to become overexpressed, resulting in developmental defects. Trisomy 62 occurs more frequently with older dams; it does not appear to be hereditary.

Around 1 in 4 fluffies born with trisomy 62 have visible deformities, such as a flattened skull (brachycephaly), cleft palate, overbite, or misshapen ears. Most foals, however, initially appear normal. Afflicted foals will open their eyes and begin walking at the usual times, but their development halts by the 3rd week of life. SBS foals do not speak - instead continuing to peep and chirp like a newborn - and can only drink milk due to their weak teeth. Growth is severely stunted, with SBS fluffies being only 15 to 30% of the size of a normal adult fluffy. Additionally, these “forever foals” cannot cope with unusual stimuli, making them highly dependent on their mothers for comfort & protection.

In addition to the developmental effects described above, trisomy 62 may also result in various forms of cardiac, hepatic, and endocrine dysfunction, further impacting overall health. These internal issues can normally only be diagnosed by a veterinarian.

Treatment is supportive only, as there is no cure for trisomy 62. SBS foals are extremely sensitive to stress and require a dedicated caregiver who can attend their special needs on a 24/7 basis. For this reason, afflicted fluffies should be sold to experienced owners only, if at all. 33% of SBS fluffies survive the first year of life, with less than 5% surviving after three years.

As an alternative to euthanasia, the FIAA’s Scientific Advisory Board has started a program to collect SBS foals as test subjects for research into genetic disorders. Breeders will be compensated at a fair market rate for each foal they provide. (Contact your local FIAA representative for more details)

Junctional Epidermolysis Bullosa

Junctional epidermolysis bullosa is a hereditary genetic disorder that results in extremely fragile skin. It is an autosomal recessive trait caused by a mutation in the JEB3 gene. This defective gene prevents the production of laminin 332, a protein which normally helps anchor the epidermis to the dermis. Without this crucial protein, the layers of skin separate very easily, even from light touches. Pegasi fluffies are most commonly affected, although all fluffies can inherit the disease.

Clinical signs of JEB develop shortly after birth. The skin of an afflicted foal will blister anywhere pressure is applied; these blisters soon burst, resulting in sloughing and ulceration. Lesions first appear on the lips and snout when the foal begins to nurse, then around the leg & wing joints, then across the entire body. Within 5-7 days the foal will have lost almost all of its skin and fluff, leaving it at extreme risk of infection or dehydration. In severe cases the hooves may detach from the feet.

Supportive treatments include sterile skin dressings, IV fluids, antibiotics, and analgesics. Most foals with JEB die within 2 weeks; a few have been kept alive with intensive care for up to 3 months, but there is no recorded instance of a fluffy with this disease being able to enjoy a normal life. Euthanasia is strongly recommended.

A DNA test is available to identify carriers of the mutated JEB3 gene, which can help prevent future occurrences of this disorder in breeding stock.

Lethal White Syndrome

Lethal white syndrome is a hereditary genetic disorder that results in a paralyzed large intestine due to malformation of the ileocolonic nerves. It is caused by a mutation in the EDNRB gene, an autosomal trait which can be either recessively or dominantly expressed. Alicorn fluffies are most commonly afflicted, with 1 in 10 carrying a copy of the defective gene. Once extremely rare, lethal white syndrome has become unfortunately common due to the popular sire effect among pedigree alicorn breeders.

As the name implies, foals with LWS will be born with a white coat. The mane & tail may be white, silver, lavender, or sky blue in color; the eyes will always be blue.

Although the foals will initially appear healthy, signs of colic and constipation will develop a few hours after the first feeding. The paralyzed colon is unable to expel feces, leading to a fecal impaction developing in the bowels. This impaction cannot be relieved by normal means such as laxatives. The abdomen will become swollen and extremely tender over the course of several days until the colon finally ruptures, leading to a rapid death from septicemia.

LWS is invariably fatal. No treatment is possible. Afflicted foals should be euthanized immediately to minimize suffering.

A DNA test is available to identify carriers of the mutated EDNRB gene, which can help prevent future occurrences of this disorder in breeding stock. The FIAA has issued new guidelines for alicorn breeders in order to increase genetic diversity and reduce the prevalence of LWS.

Cerebellar Abiotrophy

Cerebellar abiotrophy is a hereditary genetic disorder that causes degeneration of the Purkinje cells, a type of neuron concentrated in the cerebellum of the brain. It is an autosomal recessive trait caused by a mutation in the SNX14 gene. Notably, this mutation is dormant inside the developing fetus, and does not affect the foal until after birth. Cerebellar abiotrophy is slightly more common in fillies than colts.

Clinical signs of cerebellar abiotrophy do not typically appear until 4 to 12 weeks after birth. Affected foals will hold their head at a tilted angle, walk with a stiff, unsteady gait, and may show a tremor in their legs. Falls occur frequently due to ataxia as well as impaired depth perception. Behaviorally, fluffies with this disorder are hyperreactive and tend to startle easily. These traits mean that afflicted individuals are exceptionally accident-prone, even by fluffy standards.

In its more severe form, cerebellar abiotrophy can cause frequent absence seizures, loss of visual memory and language skills, and a generalized inability to determine space & position. This can potentially make even the most basic tasks, such as using the litterbox, extremely difficult for a fluffy.

Treatment primarily consists of behavioral supports & accommodations. Additionally, low doses of the drug amantadine have been shown to help improve coordination. Most fluffies with cerebellar abiotrophy can live normal, happy lives, although their owner will need to take extra precautions to avoid accidental injuries. Again, an FIAA-accredited broker can assist with finding a buyer for these special-needs fluffs.

A DNA test is available to identify carriers of the mutated SNX14 gene, which can help prevent future occurrences of this disorder in breeding stock.


Author’s note: I decided to write another one of these documentary-style pieces. Almost all of the diseases mentioned here are real conditions, albeit modified slightly to fit my headcanon.

Sensitive Baby Syndrome in particular is something that I really want to see more of. I blame No Miwkies for my obsession with the concept: I think it illustrated really well how an SBS foal can give a mare something to obsessively dote over, without the bitchiness and smarty syndrome that usually accompanies a “bestest babbeh.”

(also, watching that chubby purple foal suffer is a high that not even the strongest, most refined crack can replicate)

Anyway, if you’ve managed to get this far through my ramblings, then congrats. If you’ve got any creative ideas about how you would care for/torment a fluffy with one of these diseases, leave 'em in the replies below. Feedback is always great.


I love sensitive babbehs too.
Cute retards.


I’m also fascinated by Sensitive Baby Syndrome, and No Miwkies is probably my favourite fluffy content of all time. I would love to see more SBS foals explored, especially ways hugboxers deal with the babbeh and mummuh dynamic there.


I’m LOVING these writeups, this definitely tickles my medical literature giddy-bone.


This is very well done.

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Worth keeping in mind for all these cases.

Excellent work - made me look up Rage Syndrome, which has fine 90ties edge potential


Oh, absolutely. I think @moonbat summed it up well:

If you’re a hugboxer trying to adopt a family in this situation, you face a real dilemma.

Do you let the the vicious codependent cycle continue, possibly to the detriment of the mare’s other foals?

Or do you try to get the mare to push her “widdew sensitibe babbeh” into being a bit more independent - with the knowledge that, at least in the short term, you’d be inflicting extreme stress and anxiety onto a mentally disabled foal?

TONS of potential for great storytelling here.


Thanks for this!

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I’d love for more of these to be shown, this read is awesome.


I love the idea of birth defects being prevalent in fluffies, since they’re ostensibly man-made chimerae, and fraught with errors because they’re incomplete.


Had to blink a few times when I saw Pyloric Stenosis listed there, given I was born with the condition! Fun fact, one of the ways the doctors were able to identify the condition in addition to what’s listed here is how I was able to projectile vomit across a room! Fortunately for me, surgery was able to fully correct the issue and I don’t have any further medical issues related to the condition. Only a little scar under my rib cage from the surgery.

Other fun facts about the condition- the overwhelming majority of individuals with pyloric stenosis, according to the doctors I’ve talked to about it, are first-born, male, and of European Jewish descent. I’m only one of those, ironically.


Permission to add these to my headcanon? This is amazing.

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Damn, does this mean fluffies have 124 chromosomes at least? I guess it makes sense if they’re chimeras


Permission granted. Go nuts.


Cool, thanks! :slight_smile:

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This made me think about cerebellar hypoplasia in fluffies. Wobbew fwuffy!


Did I just spend probably 10 misreading about fictional genetic defects in fictional defective biotoy horses instead of trying to go to sleep? Yes. Yes I did. Will I regret staying up so late when I have to get up later? Probably. But man was this a damn good read. The formal document/documentary style was just perfect. Loved reading this, great work!

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