Norwich DNA health tests
There are currently seven 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).
UAS
Norwich Terrier Upper Airway Syndrome (NTUAS) is the
number one health problem in Norwich terriers.
In May 2019, European researchers published a
paper reporting on an association between a variant
in the ADAMTS3 gene and Norwich Terrier Upper Airway
Syndrome. While this is not the entire story
with regards to UAS, it is a tool that breeders can
use to try to breed away from this problem. Current
research shows that the DNA test has a (Pearson)
correlation of +0.22 with the UAS scoping test - the
gold standard with regards to UAS testing. (+1.0 being
perfectly correlated; 0 being no better than random
guessing.) Orivet
is the only lab of which I am aware that offers this
DNA test. By using linkage analysis, I am able to get
the number of risk markers from the raw data that Embark provides.
I know the values for 370 Norwich. The distribution is
that 94 Norwich have zero risk markers, 184 have one risk
marker, and 92 have two risk markers.
INPP5E (Cystic Renal Dysplasia)
In September 2018, Finnish researchers published a
paper reporting on a variant in the INPP5E
gene that causes kidney failure and death in Norwich
terrier puppies. While this variant was discovered
among Finnish Norwich terriers, the variant
is known to exist among North American Norwich.
The Cystic Renal Dysplasia DNA test is part of the Embark panel of DNA
tests.
PawPrint
Genetics offers the test for "Diffuse Cystic Renal
Dysplasia and Hepatic Fibrosis".
At a
slightly cheaper price, North Carolina State University offers
the test. To test, one starts by ordering a (free)
cheek swab kit.
I only know the name of one Norwich who carries the INPP5E
variant allele out of a total of 142 Norwich tested.
PLL
Primary lens
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 variant 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.
I know the name of 11 Norwich who carry the PLL
variant out of a total of 532 Norwich tested.
ALT
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
breeds.
According to a 2015 scientific paper,
dogs with one or two copies of an ALT variant 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 variant 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 variant has been seen in several
Norwich who are not closely related. The only
DNA lab offering to test for the ALT variant is Embark, as part of their
DNA panel test.
The ALT variant is not a health issue, but more properly
a clinical issue that a veterinarian needs to know about.
I know the names of 22 Norwich who carry the ALT
variant out of a total of 349 Norwich tested.
Several of these dogs are not closely related.
DM
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 variant in the SOD1 (exon2) gene
has been associated with DM. This variant has been found
in over 100 breeds, and is believed to be an ancesteral
mutation predating the segretation of dogs into breeds in
the late 1800s. This variant 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
Welsh Corgies.
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.
I know the names of 7 Norwich who carry the DM
variant out of a total of 308 Norwich tested.
Several of these dogs are not closely related.
ATP7B (Copper Accumulation Toxicity)
Copper accumultation toxicity is a late-onset liver disease
where toxic levels of copper accumulate and cause organ
failure. In humans, it is known as Wilson's disease.
A variant in the ATP7B gene has been seen in Norwich
Terriers that is associated with copper toxicosis.
Dogs with two copies of the variant are at high risk of
the disease.
Many commercial labs offer the DNA test for this variant
in the ATP7B gene. The ATP7B DNA test is part of the
Embark panel of
DNA tests.
I know of 7 Norwich (out of 79) who carry the allele for copper
accumulation toxicity. Several of these dogs are not closely
related.
D-Locus
The D-Locus is usually tested as as part of a DNA coat
color panel. 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 variant has also been associated with the disease
"color dilution alopecia (hairloss)".
I am aware of one Norwich reported with color dilution
hairloss, although this was before DNA testing.
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.
I know of 24 Norwich (out of 347) who carry the allele
associated with color dilution hairloss.
Embark cost-share offer
I have a cost-share
offer to encourage Norwich owners and breeders to DNA
test their dogs.
Last updated 20260530