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Havanese Club of Great Britain
DNA TESTING IN HAVANESE
Understanding genetic health
- what tests exist, what they mean, and why they matter
DNA testing sits within the first of the HCGB's three pillars of breed health: Health Testing.
But it works best when used alongside the second pillar — Genetic Diversity.
A breeding programme built on DNA tests alone, without regard for the breadth of the gene pool, risks narrowing diversity in ways that create new problems even as it addresses existing ones.
You cannot test your way out of breed health challenges without also keeping the gene pool diverse.
DNA Testing- useful, but with caution
DNA tests can be genuinely valuable tools in responsible breeding — but they have real limitations, and it is important to understand these before interpreting any result.
Many conditions have an inherited component but cannot be tested for.
Many conditions are influenced by genes AND other factors — carrying a variant is not the same as having the disease.
For some conditions, even two copies of a variant only increase risk rather than guarantee disease.
And not every available test is useful for every breed: a mutation may be common and serious in one breed and present but harmless in another.
The HCGB only supports recommendations for tests where there is good evidence of clinical relevance in Havanese specifically.
The Royal Kennel Club has produced clear guidance on how DNA test results should be interpreted and used in breeding decisions — we recommend reading this before acting on any result.
DNA tests for Havanese
The tests below are those where the HCGB considers the evidence of clinical relevance in Havanese to be sufficient to justify recommendation. However, the list is reviewed as new evidence emerges.
All tests require a simple cheek swab, collected at home using a kit supplied by the laboratory.
CDDY / IVDD — Chondrodystrophy and Intervertebral Disc Disease ⭐ Priority
What it affects: The spinal discs. Dogs with certain variants are at increased risk of disc disease, which can cause pain, weakness, and in serious cases paralysis.
The nuance: This is not a simple clear/affected test. Dogs with two copies of the relevant variant are at significantly higher risk, but not all will develop disc disease. Dogs with one copy have an intermediate risk. The test informs risk, not certainty — but it is valuable enough that the HCGB considers it a priority for all breeding dogs.
Why it matters for Havanese: Cases of disc disease have been confirmed in both UK and international Havanese.
Haemophilia A
What it affects: Blood clotting. Affected dogs are at risk of serious bleeding that is difficult to control.
The nuance: Haemophilia A is X-linked, meaning it behaves differently in males and females. Males with the variant are affected; females with one copy are carriers but generally not affected themselves. Your laboratory report will explain this in relation to your dog's sex.
Why it matters for Havanese: The causative mutation has been characterised in Havanese, and clinical cases have been reported.
Von Willebrand's Disease Type 1
What it affects: Blood clotting — a milder clotting disorder than Haemophilia A, but clinically significant, particularly around surgery or injury.
Why it matters for Havanese: Clinical cases have been reported internationally in Havanese, and the condition is well established in related small breeds.
HCOU Type 1 — Hereditary Calcium Oxalate Urolithiasis
What it affects: The urinary tract. Dogs with two copies of the HCOU Type 1 variant have a significantly increased likelihood of developing calcium oxalate bladder or kidney stones, which can cause pain, difficulty urinating, and recurrent infections.
Why it matters for Havanese: Urinary tract stones appear in HCGB health data, and the mutation is confirmed as present in the breed.
Furnishings (IC locus) — Improper Coat
What it is: This test identifies the gene variant responsible for the Havanese's characteristic long, furnished coat. Dogs with two copies of the improper coat variant produce a shorter, open coat that does not meet the breed standard.
Why it matters: A coat trait test rather than a disease test, but directly relevant to all breeding decisions.
Mutations present in Havanese — clinical significance uncertain
The following variants have been identified in some Havanese lines, but the evidence for their clinical impact in this breed is not yet sufficient for the HCGB to recommend routine testing.
This is a good example of why the existence of a test does not automatically make it useful for a breed.
- 🐾 Macrothrombocytosis — affects platelet size; clinical impact in Havanese not yet established
- 🐾 Methaemoglobinaemia — affects red blood cell function; present in some lines, no confirmed UK clinical cases
- 🐾 MTC-D (Macrothrombocytopenia) — affects platelet count; no bleeding reported in affected Havanese
- 🐾 DM (Degenerative Myelopathy) — progressive spinal cord condition; incomplete penetrance, no confirmed UK cases in Havanese
If your dog has been tested through a broad panel and returned a result for any of these variants, contact the Breed Health Co-ordinator for advice.
TESTING PROVIDERS
Choosing a DNA Testing Provider
Always use a laboratory that appears on the Royal Kennel Club’s list of approved DNA test providers.
1
Check the approved list
Confirm the laboratory is RKC approved before ordering a kit.
2
Verify your dog’s identity
Include your dog’s RKC registered name, registration number and microchip number so results can be matched correctly.
3
Keep and share your certificate
Retain a copy of every result certificate and share it with puppy buyers, stud owners and the breed club.
Genomic diversity and breed panel tests
Some laboratories offer broader breed health panels and genomic diversity testing that may not appear on the RKC list. These can provide useful additional information, particularly for breeders wishing to assess genetic diversity within their lines.
Step 6
Sharing Your Results
Every result shared with the club helps build a clearer picture of the health of the Havanese breed. Reporting results – whether clear, carrier or affected – supports responsible breeding decisions and protects future generations.
01
Keep Your Certificate
Save a copy of the official result certificate issued by your testing laboratory, showing your dog’s registered name and number.
02
Report to the Club
Use the health test reporting form to submit your dog’s results so they can be included in the club’s breed health records.
03
Share Openly
Share results with stud dog owners, puppy buyers and fellow breeders. Openness builds trust and strengthens the breed.