From:
Bruce Williams, DVM
Date: 2001-04-19 21:19:00 UTC
Subject: Re: New girl in town (Albinism)
--- In Ferret-Health-list@y..., "Brett Middleton" <brettm@a...> wrote:
> "Bruce Williams, DVM" <williams@e...> wrote:
> > However, albinism is a congenital defect in itself, due to the
> > defective migration of pigment, which never makes it to the hair
> > follicles or the iris. This is the normal albino state.
>
> I've got to disagree with this. Defects affecting embryonic
> development can certainly produce a lack of coat pigmentation to a
> greater or lesser extent -- blazes, pandas, marked white, and
> (possibly) dark-eyed white are created this way. These defects are
> also related to deafness and other neural-tube defects, as you
state.
> However, the term "albinism" is most commonly used for
hypopigmentation
> resulting from a different mechanism: the albino allele produces a
> defective form of tyrosinase, thwarting the biochemical pathway
that
> produces melanin from tyrosine.
Brett, of course you are correct. You have identified the difference
between true albinism (an enzymatic defect) and color dilution (which
is associated with abnormal embryologic development and migration of
pigmented cells from the neural crest.)
The association between diminished hearing and color dilution is not
confined to ferrets - and is also seen in other species - blue-eyed
white cats also carry a high incidence of deafness (the eyes are blue
as well due to lack of migration of pigment containing cells) and
some dalmations.
With kindest regards,
Bruce H. Williams, DVM, DACVP
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