Norwich DNA health tests
There are currently five DNA health tests that are
relevant for Norwich terriers. Four are currently
available commercially. 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.
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
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. Many
commercial labs offer the DM DNA test.
DNA testing for DM has generated controversy.
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
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
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".
Th 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. (Their panel also tests for PLL and DM, along
with over 160 other DNA health tests.)
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.
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
Currently no commercial lab is offering a DNA test for this
Last updated 20190725