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Chinese Crested Norge

DNA Testing for Chinese Crested Dogs: Which Tests Exist and What They Mean

DNA tests are available for PLL (ADAMTS17), PRA-rcd3 (PDE6A), PRA-prcd (PRCD) and the Hr locus (FOXI3) that causes hairlessness in the Chinese Crested. They tell you whether a dog is clear, a carrier or affected, so breeders can avoid matings that produce affected puppies.

What is a DNA test?

A DNA test analyses a sample, usually a cheek swab, for known mutations. For recessive diseases the result is clear (two normal copies), carrier (one copy of the mutation) or affected (two copies).

Which tests exist?

| Test | Gene | What it detects | |---|---|---| | PLL | ADAMTS17 | Primary lens luxation | | PRA-rcd3 | PDE6A | Early-onset retinal degeneration | | PRA-prcd | PRCD | Late-onset retinal degeneration | | Hr locus | FOXI3 | Hairlessness (hairless vs powderpuff) |

Recommendations differ by organisation. The American Chinese Crested club (via the AKC) recommends PLL and PRA-rcd3 testing, whereas The Kennel Club in the UK lists PLL and prcd-PRA among its tests. No single list is definitive, so ask the breeder what has been tested.

What do results mean for breeding?

For recessive diseases a carrier should only be mated to a clear dog, which produces no affected puppies. Two clear parents cannot produce an affected puppy. A negative ADAMTS17 result does not rule out every cause of lens luxation, because other causes exist.

What about the hairless gene?

Hairlessness is dominant, and two copies of the mutation are not compatible with life. Hairless dogs are therefore bred to powderpuffs in practice, and Hr testing is not a health screening requirement in the way PLL and PRA tests are.

What should a puppy buyer ask for?

Written results for both parents. See the Norwegian guide to health tests to demand.

Sources

Read more

See the health overview. Norwegian version: DNA-tester.