Considerazioni Fitz Usmany - in inglese

As written to Claudia I was not able to respond yesterday.

I do most of the list correspondence @work (shame on me) and yesterday I had too much obligations :-(



You put your finger on the spot: you can have a cat scan negative that will at some point develop the disease.

Just a small explanation on (incomplete) dominancy and recessiveness:





The Sphynx’ hairlessness is a recessive trait: a cat needs two Sphynx genes to become a Sphynx.

If there’s only one Sphynx gene …. This cat would be a carrier of the Sphynx gene – due to the recessive it can not express it.



The Russian hairlessness is caused by a dominant gene.

One gene is enough to express the trait – so a carrier of one gene is also a cat that displays the trait!



Then there are incomplete dominant traits: these genes can not overrule one another – so you get something inbetween.

Examples are the Burmese and the Siamese -> the Tonkinese or mink. Or the Sphynx and Devon -> Sphynx/Devon hybrids (or variants)







So HCM is a dominant gene: one gene is enough to express the disease. So a cat that is heterozygous for HCM (carrying one HCM gene and one non-HCM gene) is an affected cat.

Being an affected – yet heterozygous cat, doesn’t mean you have to display this.



FIRST it has a progressive onset …. It develops overtime. So a cat can have it – but does not necessarily show it as a kitten. HCM gradually develops, so a cat scanned at 1 year can give a clear scan, but scanned on 5 years can give explicitly HCM affected.



SECONDLY It has a variable expression – which means that it might show differently from one cat to the other.

It might have to do with polygenes (so other minor genes that are interacting with the respective gene!)

An example of polygenes would be “blue cats” ….. some cats are bright and dark blue (like Russian Blues) while others are pale cheapish blue …

So the same can happen with HCm affected cats. Two cats can each have one HCM gene …. One cat will have distinct symptoms while another one doesn’t have any sign, also not on scans…. But yet it still is affected!



And as ultimate bummer, you can have a HOMOZYGOUS HCM cat (carrying two HCM genes)

In that case all above cases are doubled up.

Openly discussing the problem(s) is always the beginning to overcome problems jointly.
Would love to hear experiences people had in other breeds (like heart problems Himalyans - although I was told there are different HCM genes in different breeds? like in the Coons) and other species - such as dogs.



Its almost 11:00 AM - so I have to get started