Genetic tests: what is checked

Every breed has hereditary diseases that cannot be seen at an examination or on a kitten’s ultrasound. An animal can be healthy and still carry a mutation — and pass it on to its children. That is why it is the breeding cats that are tested, not the kittens.

What is checked in Maine Coons

• HCM — hypertrophic cardiomyopathy, thickening of the heart muscle. The most common cause of sudden death in the breed. In Maine Coons the MyBPC3 gene mutation is tested.
• SMA — spinal muscular atrophy, weakness of the hind legs in young animals.
• PK-Def — pyruvate kinase deficiency, a hereditary anaemia.

What is checked in Bengals

• PRA-b — progressive retinal atrophy, which leads to blindness.
• PK-Def — the same pyruvate kinase deficiency.
• HCM — Bengals have no reliable gene test, so adult cats are checked by echocardiography; this is a heart scan, not a DNA test.

How to read the result

The laboratory report shows one of three results:

• N/N — no mutation. This animal will not pass on the disease.
• N/M — carrier. Healthy itself, but will pass the mutation to half of its offspring.
• M/M — affected animal. Not used for breeding.

A carrier may only be paired with an N/N animal — then no affected kittens are born. Two carriers are never paired with each other.

Why the parents’ tests matter more than a certificate

A vet’s certificate describes the state today: the kitten is active, the temperature is normal, the eyes are clear. It says nothing about what is in the genes — the disease will show in three to five years, when nothing can be returned or changed.