REM sleep behaviour disorder / RBD / hereditary encephalopathy (FAM8A1-related) - Russian Blue

REM sleep behaviour disorder in Russian Blue cats

This genetic test detects the FAM8A1 c.485_507del deletion that causes REM sleep behaviour disorder (RBD) in Russian Blue cats. The condition is also described as hereditary encephalopathy and can involve abnormal movements during REM sleep, vocalisation, sudden jerking or jumping, and impaired bladder control.

What does this mean for the cat?

Affected cats may show episodes in which the normal muscle inhibition during sleep is disturbed. In the described Russian Blue families, urinary retention, overflow incontinence and sometimes dilated pupils were also reported. The severity and frequency of episodes can vary between cats and may increase over time.

Practical value of this test

• Clear: the cat does not carry the tested deletion and will not pass it on.
• Carrier: the cat carries one copy and can pass the variant to offspring.
• Affected: the cat carries two copies; this genotype causes RBD in Russian Blue cats.

Inheritance

RBD caused by this FAM8A1 variant follows an autosomal recessive inheritance pattern. The test helps breeders identify carriers, plan matings more confidently and avoid affected kittens.