hey, sue! :--)

i was told by my biology-prof that it was sex-linked in frequency - and i did not argue with him, LOL, i accepted it as fact.
(shrug) so if its wrong, i quoted it in innocence, and am perfectly happy to get more accurate info! ;--)

here is a genetic + developmental article on How + Why
the white coat / blue eyes combo creates deafness, by a (human) physician:
Deaf cats draw a blanc › Dr Karl's Great Moments In Science (ABC Science)


and a research-article on the genetics
------------------------------------------------
Does a pleiotropic gene explain deafness and blue irises in white cats?
The Veterinary Journal, Volume 173, Issue 3, May 2007, Pages 548-553
Caroline A. Geigy, Silvia Heid, Frank Steffen, Kristen Danielson,
André Jaggy, Claude Gaillard

Abstract
--------------------
The prevalence of deafness is high in cat populations in which the dominant white gene is segregating. The objective of this study was to investigate whether there is a gene that is responsible for deafness as well as for blue eyes and to establish a plausible mode of inheritance. For this purpose, data from an experimental colony with deaf cats were analyzed. The hearing status was determined by acoustically evoked brain stem responses (BAER). Complex segregation analyses were conducted to find out the most probable mode of inheritance using maximum likelihood procedures. The prevalence of deafness and partial hearing in the experimental colony was 67% and 29%, respectively. The results of the bivariate segregation analysis support the hypothesis of a pleiotropic major gene segregating for deafness and blue iris colour. The high heritability coefficients for both traits, 0.55 and 0.75 respectively, indicate that beside the major gene there is an important influence of polygenic effects.
Article Outline

1. Introduction
2. Materials and methods

2.1. Segregation analysis

3. Results

3.1. Prevalence
3.2. Segregation analyses

4. Discussion
5. Conclusion
Acknowledgements
References

-------------------------------

also an interesting article here, from Louisiana State-U:
http://www.lsu.edu/deafness/genet.htm

that one includes a table of affected breeds carrying the W gene (13).
EXCERPT -
>> The white (W) pigment gene in cats is autosomal dominant over color, and is unrelated to albinism (Little, 1957; Searle, 1968). Cats carrying the W gene are not always solid white, often having colored spots on their heads that may disappear with age. Unlike dogs with the merle gene, homozygous white cats do not have visual or reproductive defects, but they are more prone to the occurrence of blue irises and deafness, either unilateral or bilateral, and deafness occurrence increases with the number of blue eyes (Delack, 1984). Whether the cat is heterozygous or homozygous for W, the blue eyes and deafness have incomplete penetrance. Long-haired cats have a higher prevalence of blue eyes and deafness than short-haired cats (Mair, 1973). White cats carrying the underlying cs Siamese dilution pigment gene can have blue eyes without deafness, and it has been suggested that the presence of this gene explains why purebred white cats are less often deaf than mixed-breed white cats (Pedersen, 1991).
A dominant piebald gene (S) is also found in various cat breeds (Pedersen, 1991; Searle, 1968), but there has been no report of deafness associated with its presence.

diagnosis of deafness (BAER)
Temp\diagnosis.htm

excerpt: in DOGS -
>> In the absence of a reliable blood test to identify carriers of deafness genes in dogs, efforts are currently underway to establish a hearing registry in the United States, whereby dogs certified to have normal bilateral hearing would be registered to enable breeders to reliably select mates for their own animals to minimize the production of deaf offspring. <<

and from
http://www.lsu.edu/deafness/prevalence.htm

EXCERPT -
>> When Mair (1973) and Bergsma & Brown (1971) examined the effect
of blue eye color on deafness, they found, respectively, a prevalence of
deafness (unilateral and bilateral combined)
of 85% and 64.9% in cats with two blue eyes,
40% and 39.1% in cats with one blue eye,
and 16.7% and 22% in cats with no blue eyes. <<

so... if gender has No Effect on deafness, then the 85% deafness is actually correct,
in that 85% of white cats with both eyes blue ARE unilaterally deaf, whether they are Male or Female makes no difference! LOL....
thats hysterical, i WONDER if that $%#@! stinker, Bill Cramp (my Bio-Prof) set me up! he is probably long-dead, but if this is his twisted sense of humor so many years later, it would not at all surprise me...

more than 30-years is a long time to wait for a punchline to hit home...
wow, that has me shaking my head + chuckling!
--- terry

terry pride, APDT-Aus, apdt#1827, CVA, IPDTA, TDF