Neural Crest/Waardenburg Syndrome

Waardenburg Syndrome

Waardenburg Syndrome (WS) is a type of genetic condition known as a neural crest disorder. Of note, there are other potential types of neural crest defects, but in ferrets all neural crest defects tend to be lumped into the category of Waardenburg Syndrome due to the fact that we have little to no research (and no testing available to owners) to differentiate between other potential causes of neural crest defects/syndromes in ferrets.

Waardenburg Syndrome is a genetic defect that runs on a spectrum of severity. It is often correlated with high amounts of white markings, though you can have a “Waardy” without white markings, and a ferret with white markings who is not a Waardy. The genes for white markings and Waardenburg are very closely associated though, and often come hand in hand. [Of note, high-white markings specifically on the head in ferrets (blaze and panda) are, to our current knowledge, always due to a neural crest defect.] The syndrome can range from very mild with minimal symptoms to severe and may include features such as: deafness, cranial defects, broad skull, wider set eyes (think of Down Syndrome), and gastrointestinal problems. In ferrets with WS, owners often also notice cognitive deficits, behavioral differences, lack of appropriate social skills, and even (anecdotally) abnormal gait – among other symptoms. Waardenburg ferrets also tend to have more health problems and a shorter lifespan.

You can also have some of these features without WS too though, such as a deaf ferret who does NOT have WS, congenital defects, and other issues.

An excerpt from Wikipedia on Waardenburg Symptoms (note that this article is referring to humans, but the same features apply in other species):

Signs and symptoms
There are five major and five minor diagnostic criteria for Waardenburg syndrome.


  • sensorineural hearing loss
  • iris pigmentary abnormality (two eyes different color or iris bicolor or characteristic brilliant blue iris)
  • hair hypopigmentation (white forelock or white hairs at other sites on the body)
  • dystopia canthorum (lateral displacement of inner canthi)
  • first-degree relative previously diagnosed with Waardenburg syndrome


  • skin hypopigmentation (congenital leukoderma/white skin patches)
  • medial eyebrow flare (synophrys)
  • broad nasal root
  • hypoplasia alae nasi
  • premature graying of the hair (before age 30)

What does all of that mean in English?

  • deaf or hard of hearing
  • abnormal eye color
  • patches of white fur on the forehead, and other areas of the body
  • wide-set eyes (dystopia canthorum)
  • First degree relative (parents, siblings, offspring) with WS
  • white skin patches (in humans or animals with dark skin, this can be much easier to see. In ferrets it may be harder to determine, and may show up as white or pale areas of fur as these are areas that are low or lacking in normal pigment)
  • close-set eyebrows or “unibrow” (medial eyebrow flare/synophrys) – clearly this applies more to humans
  • broad bridge of nose
  • hypoplastic alae nasi is a deformity of the nose in humans; does not apply so much to ferrets
  • early graying or “roaning out” (turning gray/white)

Here is a great example from a forum member’s ferret Javik. He shows classic Waardy head shape and markings. Note the broad flat skull, high nose bridge, wide-set eyes, the panda markings, as well as the white patches on his stomach in the first picture.

Photo Credit: McKenna Schmitt Ferret: Javik
Photo Credit: McKenna Schmitt Ferret: Javik
Photo Credit: McKenna Schmitt Ferret: Javik
Photo Credit: McKenna Schmitt Ferret: Javik
Photo Credit: McKenna Schmitt Ferret: Javik
Photo Credit: McKenna Schmitt Ferret: Javik

Another Waardy named Leonard – again, note the unique features….

Photo Credit: Celene Hoag Ferret: Leonard
Photo Credit: Celene Hoag Ferret: Leonard

Some good threads to read:

Here is a very good post by Josiesmom on the old forum:

Waarednberg Syndrome technically only applies to humans, not ferrets. The actual problem is “Neural Crest disorder.” A problem in neural crest cells wherein they do not develop properly. These cells begin in the embryonic stage and migrate throughout the embryo to become other organs, cartilage, nerves and tissues.

GO here to learn some more on neural crest cells:

When these cells have a disorder the organism can develop albinism, melanoma and other neurocrestopathies. Internally this can mean the animal’s nervous system is not as developed as it should be, its digestive system is not properly innervated even its bones can be affected!

Outwardly this results in a ferret (or animal) with a lot of white on its head and many other white markings too- white mitts, tip of the tail, knees. The head markings could be a blaze, one or both ears are all white, the entire head is white, they have a white bib too or a white cape.

Their head tends to be broader with the eyes set a little lower and they exhibit a “baby face.” They are usually totally deaf or have a hearing impairment. This stems not as much from improper nerve channels as much as it is from actually improper formation of the cochlea bone within the ear itself!

Often the nerve channels in the cervical spine are narrower and sometimes deformed.

The ferret’s jaws don’t open as wide as normal ferrets.

There seems to be a connection of ferrets with Neural crest disorders and other diseases too. My vet thinks that becauase Josie was born a Panda, this predisposed her to the Juvenile Lymphosarcoma.

Animals with white markings are often sought after at pet shops and breeders because they are considered more “cute” than their counterparts that exhibit “normal” coloration.

Neural Crest Disorder may be tied in with the fox “star gene” which has been shown to show up when subsequent generations are bred for “domesticity.” Humans tend to breed for considerable white markings in many animals and after generations of these breedings, only then after other health problems have become prevalent do they begin to realize that while white markings ARE found in nature, they are there as warnings or camouflage. The white markings are generally NOT on the head- but rather along the ventral surface or edges.

Humans will breed for a “star,” which becomes a strip, which becomes a blaze, which then begets white sox, and then maybe a white ear, then two white ears and a bib, then finally we end up with a cute white faced animal with a bib, four white sox and a cute white tail- but the animal now has other problems!

Ferrets since the early days of domestication were selected for albinism because it is easier to find a white ferret in the thicket than a sable ferret! also the more white an animal has on it, the less “wild” it is perceived to be.

This is a good site to understand the fox “Star gene:”

And this is a great site to understand deaf ferrets:

In short to improve the health of a species, they need to stay as close to their natural form as possible!


Original Post:

And a helpful video on how to tell if your ferret is deaf: