>From: William Killian - Zen and the Art of Ferrets <[log in to unmask]>
>Subject: zen on deafness in blazes...
>>Can anyone out there please tell me where I can find info regarding
>head. As I was told pigment cells are involved in hearing somehow.
>When the pigment cells are in a "pattern" that involves the auditory nerves
>then hearing is impaired. I think it was Dr Williams who explained the
>pigment portion.
>b&d
 
Hearing loss, pigmentation changes in hair, skin, and the iris of the eye
and in type I Waardenburg syndrom, a change in the shape of the eye and
placement of the tear duct, are all related defects that are not in and of
themselves causative of this disorder.  There may be multiple genes that,
when mutated, lead to this syndrome but most likely the genes involved are
important for setting up developmental and cell migratory pathways.  When
this is disrupted, nerve tracts (such as the cochlear nerve) don't always
get laid down correctly and pigment cells don't always migrate to the
appropriate place.  One candidate gene is a gene calle PAX3 which is known
to be important for early development of the head.  The severety of the
syndrome varies with the different types of mutations of the genes involved
in setting up the developmental program.
 
This is not a good thing to be breeding for!!!
See below for a reasonable description of the syndrome.
 
http://www.boystown.org/deafgene.reg/waardsx.htm
 
Keep in mind that not all deafness is due to Waardenburg syndrom.
 
Max
[Posted in FML issue 2763]