What to know?
The Maine Coon is a cat that got to Italy less than 40 years. The first specimens caught on quickly even in cat shows, which at the time were very popular. But together with their legends on unlikely crossings with lynxes or raccoons, they carried an annoying reputation about some heart diseases to which would be predisposed.
In 2004, it was discovered the gene whose mutation is responsible for 90% - 95% of cases of Feline HCM (Hypertrophic Cardio Myopathy, lethal heart disease). In 2005 was marketed the test for identifying the subjects carrying this mutation (A31P) and it was possible to begin to breed, largely avoiding the possibility of giving birth to creatures with a sad destiny. In fact, thanks to the introduction of mandatory genetic tests and ultrasound heart controls in breeding animals, the incidence of the disease has become much lower, such that it no longer exists associated with the Maine Coon. We now know that it wasn't about predisposition of the breed, but of a disease widespread in all cats, whether purebred or not.
Another annoying rumor is related to Hip Dysplasia. The Maine Coon is a big cat, but that doesn't mean that more than other breeds are predisposed to illnesses resulting from dysplasia, neither to osteoarthritis nor to other diseases of the joints.
The truth is that it is a natural breed, very strong and sturdy.