Norwich DNA health tests
There are currently six DNA health tests that are relevant
for Norwich terriers. All of these tests are inexpensive and
require nothing more than a swab of the inside of a dog's
mouth in order to get a DNA sample to test. In order of
importance (in my opinion).
Norwich Terrier Upper Airway Syndrome is the
number one health problem in Norwich terriers.
In May 2019, European researchers published a
paper reporting on an association between a mutation in
the ADAMTS3 gene and Norwich Terrier Upper Airway Syndrome
(NTUAS). While this is not the entire story with regards to UAS,
it is currently the only tool that breeders have to try to breed
away from this problem. VetGen is
the only lab of which I am aware that offers this DNA test.
INPP5E (Cystic Renal Dysplasia)
In September 2018, Finnish researchers published a
paper reporting on a mutation in the INPP5E
gene that causes kidney failure and death in Norwich
terrier puppies. While this mutation was discovered
among Finnish Norwich terriers, the mutation
is known to exist among North American Norwich.
The only lab in North America currently offering a
DNA test for the INPP5E mutation is a
genetics lab at North Carolina State University.
To test, one starts by ordering a (free)
cheek swab kit.
luxation (PLL) is an eye disease found mostly in the
terrier breeds . Some Norwich have been diagnosed with
PLL. These Norwich and related Norwich have been found
to carry the mutation in the ADAMS17 gene believed to be
the cause of PLL and diagnosed
by the PLL DNA test.
Many commercial labs offer the PLL DNA test.
OFA maintains a database of PLL DNA reports.
The PLL DNA test is part of the Embark
panel of DNA tests.
Alanine aminotransferase, or ALT, is a common value on
most blood chemistry panels and is known to be a sensitive
measure of liver health. Labs give a reference range for
normal ALT values. This reference value was determined
from the ALT results of lots of healthy dogs of many
According to a 2015 scientific paper,
dogs with one or two copies of an ALT mutation may
have "low-normal" ALT activity. This is not a
disease state. Rather it is a clinical finding - dogs
with low-normal ALT activity have lower resting levels
of ALT activity. In other words, the reference range for
dogs with the ALT mutation is different (lower) than for
the general dog population. This means that if the ALT
activity rose, it still could fall within the range the
lab reports as normal and might be missed by a veterinarian
who was not aware that the dog is a "low-normal".
The low-normal ALT mutation has been seen in several
Norwich who are not closely related. The only
DNA lab offering to test for the ALT mutation is Embark, as part of their
DNA panel test.
Degenerative Myelopathy (DM) is an adult-onset,
progressive spinal cord disease causing weakness in the
hind limbs and eventually paralysis. Because common
spinal cord injuries can mimic DM, a definitive diagnosis
can only be made by a postmortem examination
of the spinal cord. No Norwich has been definitively
diagnosed with DM. A veterinary neurologist reported
a Norwich with DM, but unfortunately the spinal cord was
not postmortemly examined.
A mutation in the SOD1 (exon2) gene has been associated with DM.
This mutation has been found in over 100 breeds, and is believed
to be an ancesteral mutation predating the segretation of dogs
in breeds. This mutation exists in Norwich terriers.
DNA testing for DM has generated controversy among breeders.
Some argue that since no Norwich has been definitively
diagnosed with DM, that there are modifier genes that stop
Norwich from getting DM. However no evidence has been
presented that such modifier genes exist for Norwich nor has
any search been made for modifier genes among Norwich. A 2016
paper reported that a modifier gene had been found in Pembroke
Many commercial labs offer the DM DNA test.
OFA maintains a database of DM DNA reports.
The DM DNA test is part of the Embark
panel of DNA tests.
The D-Locus is usually tested as as part of a DNA coat color
The recessive allele d in the "D locus", located in the
MLPH gene, causes (where there are two copies of d) a
color dilution in a dog's coat color. This mutation has also been
associated with the disease "color dilution hairloss".
To my knowledge no Norwich has been reported with "color dilution
Many commercial labs offer the D-Locus DNA test.
OFA maintains a database of D-Locus DNA reports.
The D-Locus DNA test is part of the Embark
panel of DNA tests.
Last updated 20200531