MCAD deficiency / MCADD (ACADM-related) - Cavalier King Charles Spaniel

What does this test analyse?

This genetic test analyses the ACADM c.444_445delins-variant in the Cavalier King Charles Spaniel. The condition is known as MCAD deficiency, MCADD or medium-chain acyl-CoA dehydrogenase deficiency.

What does this condition mean?

MCAD is an enzyme needed to process medium-chain fatty acids as an energy source. In dogs with two copies of the tested ACADM variant, this fatty-acid metabolism is disrupted. This can lead to metabolite accumulation and neurological episodes such as lethargy, reduced responsiveness, ataxia and complex focal seizures, especially when energy metabolism is under pressure.

Inheritance and result

The trait is inherited as autosomal recessive. A dog with one copy is a carrier and can pass the variant on without developing the tested form. A dog with two copies has the genotype that causes MCAD deficiency.

Practical value of this test

This test has practical value for breeders, owners and veterinarians because carriers can look healthy while the variant remains present in a population. The result supports breeding selection, risk management and interpretation of neurological or metabolic signs.

• Helps avoid carrier-to-carrier matings that can produce affected puppies.
• Supports selection within Cavalier lines where the variant may occur.
• Adds valuable context for dogs with recurrent lethargy, ataxia or seizure-like episodes.
• Makes family-line investigation and future mating planning clearer.

Result in brief

• Clear (N/N): the tested delins variant was not detected.
• Carrier (N/delins): one copy was detected; the dog can pass the variant on.
• Affected genetic result (delins/delins): two copies were detected; this genotype causes the tested form of MCAD deficiency.