The other two entries: hips and SMA
Hip dysplasia and spinal muscular atrophy in the Maine Coon: prevalence figures, testing, and why a heavy breed reads its joints differently.
The Register's newsroom · · 3 min of reading
HCM gets the headlines. Two quieter entries belong in the same file: hip dysplasia and spinal muscular atrophy, both documented in the breed and both handled by testing rather than worry.
Hip dysplasia
The Maine Coon is one of the largest domestic breeds, and large cats wear their joints the way large dogs do. Radiographic studies and registry screening programmes have found hip changes in a substantial minority of tested cats, with figures varying by population and by how strictly the X-rays are read. The breeding-safety literature written for dog breeds applies the same logic here: test the parents, record the scores, select on the numbers. Most affected cats show nothing at home for years, because cats compensate silently and owners do not radiograph a cat that jumps normally.
The practical consequence is for breeders and buyers, not for the living room. Breeding cats can be radiographed and scored under programmes run by the same organisations that grade dogs' hips, and an honest breeder either has the scores or says why not. A buyer can ask a breeder whether the parents' hips have been scored, and an honest breeder either has the scores or says why not.
Spinal muscular atrophy
SMA in the Maine Coon is an inherited motor-neuron disease: kittens lose muscle tone in the hindquarters early, stay alert and pain-free, and live shortened lives. It is caused by a recessive mutation in a gene called LIX1, which makes it the simplest kind of problem to manage: carriers are healthy, the DNA test is definitive, and two carriers should never be mated. The mutation persists in the gene pool, so the test remains part of a serious breeding programme rather than a historical footnote.
Reading a health file as a buyer
A complete health conversation with a breeder covers three tests: the heart scan, the hip score and the SMA DNA result. Each answers a different question, and none replaces the others. A breeder who volunteers all three without being asked is telling you more than any of the results alone.
The signs a household actually sees
A cat with hip trouble rarely limps. It stops climbing to the top of the cat tree, hesitates before jumping down, starts using the lower shelves. Because Maine Coons are calm to begin with, the change reads as laziness or age. A young adult that quietly reorganises its vertical life is worth a veterinary conversation, not a larger cushion.
Why the file keeps both together
HCM, hips and SMA form the breed's complete documented risk set: one scanned, one scored, one genotyped. The three mechanisms differ so completely that "health-tested parents" is meaningless without the breakdown. The Register prints the breakdown because the short version is exactly what weak sellers hide behind.
Reading the scores
Hip scores come back as grades, excellent through severe, and the breeding decision is the registry's business rather than the pet owner's. What the owner needs is the fact of the test: a breeder who has spent money radiographing cats that will never limp is a breeder spending money on the invisible parts of the breed, which is where all the serious costs live.
The pet owner's version
At home, the tests reduce to observation. A cat that stops jumping to its old heights, lands heavily, or hesitates on stairs is reporting its joints. The fix is early and ordinary: keep the weight honest, keep the climbing options low as the cat ages, and let the vet see the gait once a year.
