This is probably THE single most important thing to read (and if from a
genetics professor, Dr, Brett Middleton):
http://ferrethealth.org/archive/YG3069
 
The neural crest is a very early fetal crest of cells.  These cells will
later differentiate into multiple types of cells.  It exists before
there are organs, senses, etc.  Before the neural crest there is the
cardiac neural crest which later differentiates into the cardiac crest
(which forms major components of the cardiovascular system) and the
neural crest.
 
Remember all the stuff in the news recently after Bush vetoed the Stem
Cell Bill which would have let extra very early fetuses destined to be
thrown away -- blastulas which look like little hollow soccer balls --
instead be used to help develop medical approaches for diseases like
Juvenile Diabetes, Parkinson, etc.  Okay, remember from all of those
news reports that stem cells are important because they differentiate
into the vast array of cells later.  Okay?  We aren't talking quite that
early, but still early enough that multiple things come from the crests.
 
Because mutations to the neural crest cells happen so very early they
can affect a vast number of cells, and which ones they affect and how
badly can vary quite a bit among individuals.
 
As the name sounds, most of what they become is neural, and not just
the parts that let individuals feel or move.  There are parts like the
sympathetic nervous system and parasympathetic nervous system which
allow organs to function properly.  In fact, although it is possible
that some mutations which affect the earlier cardiac neural crest
are part of the reason why cardiomyopathy is more common in such
individuals, it is now thought that damage to those systems plays
a greater role.  Again, research is on-going.  BTW, the form of
cardiomyopathy which occurs is much greater proportion in individuals
with neural crest mutations is the harder one to spot, hypertrophic
cardiomyopathy, though dilated cardiomyopathy rates are also higher.
 
The effects on parasympathetic and sympathetic nervous systems are
under study in relation to some kidney diseases.
 
These cells affect head pigment, and the cells which make up some
structures for hearing and for development of parts of the mandible
(lower jaw) so ferrets with neural crest variations can wind up deaf or
partly deaf, or wind up unable to open their jaws fully.  There is some
on-going research into dysphagia (poor swallowing) going on in relation
to the mutations.  That means that these ferrets might be more prone to
problems related to poor swallowing such as aspiration pneumonia.
 
According to a genetics councilor neighbor (who recently moved away to
marry) in humans there are central nervous system studies going on,
too, to see what difference may exist on that regard.
 
Some types of neural crest mutations are related to increased
malignancy rates.
 
Some are associated with increased rates of polydactyly (extra fingers
or toes) or syndactyly (the toes or fingers in sheaths).  There is
more.  Some individuals, like our late Scooter who had syndactyly to
the point where mangled claws erupted from his pads, can have multiple
serious problems; he also had related GI problems which were what
finally killed him.
 
The markings associated with neural crest variations are white head
ones like blazes or panda heads, and some also have body spotting.
Incomplete, non-bilateral bibs or mitts which may have uneven margins
are associated with neural crest mutations, but complete, bilateral,
evenly margined ones that completely replace the dark mitts and bibbs
appear to have an entirely different cause because they have not been
associated with medical problems and seem to exist in only a narrow
range of pigments for the main coloration.
 
-- Sukie (not a vet, and not speaking for any of the below in my
private posts)
Recommended health resources to help ferrets and the people who love
them:
Ferret Health List
http://www.smartgroups.com/groups/ferrethealth
FHL Archives
http://ferrethealth.org/archive/
AFIP Ferret Pathology
http://www.afip.org/ferrets/index.html
Miamiferrets
http://www.miamiferret.org/fhc/
International Ferret Congress Critical References
http://www.ferretcongress.org
[Posted in FML issue 5313]