Thread: Any people with HCM positive MCs here?

Good to hear your 5 year old hetero is totally negative on echo still (as was ours at 4...they are close in age actually).

The original Meurs paper on her mutation discovery is rather alarming:

Of the 10 cats with a heterozygous mutation, three are still alive at 8–12 years of age with moderate disease and only one died suddenly, a larger number of these cats developed severe HCM and died of heart failure. One died of an unrelated cause.

The Meurs paper can be read/downloaded for free from:
A cardiac myosin binding protein C mutation in the Maine Coon cat with familial hypertrophic cardiomyopathy -- Meurs et al. 14 (23): 3587 -- Human Molecular Genetics

There is a more recent German study that is more hopeful:
Wiley InterScience

This paper is not available for free (as far as I know), but I have a copy. A couple of key quotes from the paper:

In our study, although many of the recruited Hetero animals were young and therefore may not have fully expressed their phenotype, >25% of Hetero cats with normal echocardiography were >4 years old, with ages ranging from 4.1 to 11.5 years. This suggests that the MyBPC3-A31P mutation may be associated with a benign course of the disease at least in some Hetero Maine Coon cats.

In conclusion, this study demonstrates that the heterozygous status for the MyBPC3-A31P mutation is not systematically associated with occurrence of LVH and major myocardial dysfunction in the Maine Coon breed, as some Hetero cats may live years without overt signs of HCM and with only minor regional diastolic myocardial dysfunction. Further studies with long-term longitudinal follow-ups of Hetero cats are however required to better establish the MyBPC3 genotype-phenotype correlations in older animals.

(LVH stands for left ventricular hypertrophy--the essence of HCM.)

This is obviously much better news for hetero cats! Let's hope it is the more accurate (it was done with a larger population of heteros, 38, than the earlier paper, 10). The cats were not that old, however, so what will happen as they approach 8-10 is less clear.