X-linked myotubular myopathy / XLMTM (MTM1-related) - Maine Coon cat

What does this test analyse?

This DNA test analyses the MTM1 variant c.455C>T in Maine Coon cats. The disorder is described as X-linked myotubular myopathy, XLMTM, myotubular myopathy 1 and belongs to the group of centronuclear/myotubular myopathies.

What does the disorder mean?

MTM1 is located on the X chromosome and is important for normal muscle function. An affected male cat with the variant on its X chromosome can develop progressive neuromuscular signs. Reported signs include abnormal gait, generalised muscle weakness, difficulty eating or walking, reduced muscle mass and limited ability to fully open the jaw.

• Clear: the tested variant was not detected.
• Carrier: in a female cat, one copy means she can pass the variant to kittens.
• Genetically affected result: in male cats, one mutant X chromosome can cause disease; two variant copies in females represent a severe risk genotype.

Practical value of this test

The test is valuable for Maine Coon breeders who want to identify and manage carrier status. Because X-linked inheritance can affect male cats most severely, the result helps plan matings, recognise female carriers and greatly reduce the chance of affected kittens.