Reply from breeder re: HCM screening - what do you think?

junglerose · **Posted:** Fri Jul 02, 2010 9:04 pm

Scanning needs to be seen as a screening tool. On the day it will tell you whether the cat has HCM or not, that part is very accurate.
What is "inaccurate" is that 2 years later the "negative" cat can die from HCM.

We do not know the types of HCM that are present in Bengal cats, (the research was done primarily in Maine Coons).

In humans the different mutations cause different types of disease with different ages of onset. Different families tend to have different mutations.
I am certain we will find the same thing in cats.

Some types of HCM in Bengals may cause disease before birth causing stillbirth, some at around 6-12 months, others at 2 years, some at 3 years etc. etc. and some even at over 8 years. No research has been done so no-one really has any idea apart from anecdotally.

It does appear that there is a type in Bengals that hits the young ie less than a year and another type that hits at 2-4 years of age, the evidence for older cats is lacking due to the lack of follow up and the difficulty of diagnosis in the community.

A scan done at 18 months may be too late if the cat has died of HCM at 9 months, just right if the cat is on course to die at 2 years and too early if the cat has a type of HCM that shows up at 8 years.

However the object of the exercise is really to try and second guess this disease, to pick it up as early as possible to minimise the damage before there are litters upon litters on the ground spreading the disease even further and to reduce the number of kittens born with death sentences hanging over them.

HCM is a progressive disease, so a negative scan says nothing about long term prognosis, a positive scan done at whatever age says a lot. It says the cat has the HCM gene and is capable of passing it on to its offspring. It also tells us that one of its parents has the HCM gene, and that its siblings and its progeny have a 50% chance of having the gene too.

Hoshimi · **Joined:** Thu Jul 03, 2014 4:52 pm **Posts:** 3

junglerose · **Posted:** Fri Jul 04, 2014 11:57 am

I think what some breeders do not understand is, that screening is done to identify positives, not to identify negatives.
They want a test that can show the cat is safe to breed from and that is not possible with scanning.

As HCM is an autosomal dominant genetic disease, then identifying positives by scanning means that we can also identify related cats that are at high risk of developing the disease i.e. by studying pedigrees and removing high risk cats from breeding programs.

Unfortunately, very often I see cats that scan positive, yet some breeders continue to breed their siblings, progeny and one or other of the positive cat's parents too.
The likelihood of such close relatives having the disease or are capable of passing it on to progeny, is at best 50%.
The justification offered by those breeders and others in the breed, is that if we were to neuter all of those risky cats then the breed would suffer.
However, cats get neutered by breeders every day, often because the progeny or the cat itself is not good enough in the looks department.

So it appears that, whilst it is OK to reduce the gene pool by neutering "bad looking" cats, it seems it is NOT OK to neuter because the cats have a potential health issue...

Reply from breeder re: HCM screening - what do you think?

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