Hereditary necrotizing myelopathy / HNM (IBA57-related) - Nederlandse Kooikerhondje

What does this test assess?

This genetic test analyzes the IBA57 variant c.439C>T for Hereditary necrotizing myelopathy / HNM in the Nederlandse Kooikerhondje. The condition is also described as hereditary necrotizing myelopathy, HNM, ENM, necrotising myelopathy, Kooiker paralysis, leukodystrophy and IBA57-related myelopathy.

What does this condition mean?

HNM is a severe progressive neurological disorder of the spinal cord. In affected Kooikerhondjes, signs usually start at a young age with hind limb weakness, paresis and ataxia. The disorder can progress to paralysis of all four limbs. IBA57 encodes a mitochondrial protein involved in iron-sulfur cluster function; nervous tissue is particularly sensitive to disruption of this pathway.

Inheritance and result

The trait is inherited as an autosomal recessive condition. Dogs with two copies of the tested variant are expected to be affected. Carriers have one copy, often look healthy and can still pass the variant on.

• Clear: the tested variant was not detected.
• Carrier: one copy of the variant was detected; this is mainly important for breeding plans.
• Affected: two copies of the variant were detected; this genotype causes this condition for this variant.

When is testing useful?

Testing is useful for breeding animals, young dogs from Kooiker lines and dogs with early coordination or mobility problems where HNM is part of the differential diagnosis. Because carriers can be clinically healthy, the test is especially powerful before breeding decisions: it shows which combinations are safe and which can produce affected puppies.

Practical value of this test

The test makes hidden carrier status visible and helps breeders, veterinarians and owners make decisions based on concrete genetic information.

• Helps identify carriers in a small breed population.
• Supports avoiding carrier-to-carrier matings.
• Reduces the risk of puppies with progressive paralysis.
• Provides clear genetic information for breeding advice and follow-up of risk lines.