It means that either the dam was not tested before, or that she was tested and the cataract was not evident at that time (which is why the eye test must be carried out annually on all breeding stock).

The cataracts malamutes are predisposed to can occur anytime between about 8/9 months and 6 years (though current thinking states that it could be as late as 8 years before it is first seen, though this is in rare cases). Most are diagnosed fairly young though.

So it is possible that a bitch can be bred from before it appears, which is another reason why people should not have multiple litters from a younger bitch .

In a way, yes that is right. However there are many causes of cataracts, one example being trauma. This is unique to the individual dog and can not be passed on. The opthamologist will be able to diagnose the particular type of cataract a dog has when they are tested. Cataracts occur in different parts of the lens and where they appear tells the opthamologist what type of cataract it is and whether it is hereditary or not.

Ok, and has it been determined whether it is a dominant or recessive ?

Not that I am aware, but Boston's aren't one of my breeds. Either way, the dam is affected and should not be bred from as she will pass it on.

Well as far as I know, she was tested anually clear, so it must have been undetected. Thanks.

Right that's what I thought. The above mentioned bitch was diagnosed at age 4, after her daughter was diagnosed at age 2.

Yes, well with the Boston he did also mention that there was trauma on the front of the eye, which was visible to the naked eye, but he then showed us the HC which was at the back.

That makes sense, Thanks

That's what I thought. OK, can you tell me where that excerpt came from, so I can pass that on to her and try to explain the best I can ?

No problem

It is part of a paper written by Cathryn Mellersh (among others) for Journal of Hereditary. She led the team who found the marker gene for EHC in Bostons

Brilliant, I'll have a look and probably have to read all this again, just to get it clear ..lol

Thanks Kirsty

Thats ok

(Now if you had just said it was Boston's in the first place, we could have had this all wrapped up in a page Just kidding ).

Anyway, goodnight

I didn't realise it would have made a difference, I do now

Night hun

I can't comment on Bostons or Mals but Siberians are also affected by HC which can be late onset. HC in Siberians is known to be recesive so 2 dogs that pass their eye tests clear can still produce affected offspring if they are carriers.

2 carriers together will produce:
1 in 4 clear
1 in 4 affected
2 in 4 carriers

a carrier to a clear will produce
1 in 2 carriers
1 in 2 clear
no affected

clear to clear will only produce clear
affected to affected will only produce affected

until the marker gene has been identified, the only way to know if a dog is a carrier is if it produces an affected offspring.

Senile cateracts look different to HC and are not hereditary. I also know of dogs that were hand reared and developed nutritional cateracts, again not hereditary.


It is on the SSHC and SHCGB code of ethics that any dog failing it's eye test must not be bred from but siblings of affected dogs and known carriers can still be bred from (so not to reduce the gene pool) but all care must be taken to avoid breeding with other carriers.