The Welsh Terrier Club

The Welsh Terrier Club

Welsh Terrier Breed Health

To date the health of the Welsh Terrier has remained in a good state. However the club takes this matter very seriously and has appointed a breed health representative Alexandra Witmond.

If you have any questions or concerns then please feel free to contact her. Either by Tel. 01279 635130 or E-mail



Masticatory Muscle Myositis is an autoimmune disorder in which antibodies attack the
2M fibres in the masticatory (chewing) muscle group.

Although MMM can occur in any breed, it occurs more commonly in large breeds such as
Golden Retrievers, Doberman Pinschers, German Shepherds, and Labrador Retrievers. Young
Cavalier King Charles Spaniels may be severely affected.

The condition occurs in males and females with an average age of onset of 3 years, though
puppies as young as 4 months have been affected. Fortunately, if MMM is diagnosed early ,
dogs can be treated to increase the likelihood of a full recovery.

Research of this disease at the University of California San Diego led to the development of a
blood test in 2004 that detects the presence of 2M antibodies and accurately identifies affected
dogs. The team identified type 2M fibres in the Masticatory muscle group and showed that
antibodies against type 2M fibres are involved in the pathogenesis of MMM.

MMM is an inflammatory myopathy. It is a unique myopathy or a muscle disease in which dogs
commonly have jaw pain and inability to open the jaw.

The genetic components of autoimmune disease are very complex. Although a great deal of
research has been done to identify the causes of human autoimmune disease, much less
research has been done in dogs. Genes play a role in increasing susceptibility to autoimmune
disease but ENVIROMENTAL triggers initiate the onset of clinical signs.

In dogs that are predisposed to autoimmune reactions, suspect triggers include viral and
bacterial exposures, possibly vaccinations, hormones, stress, allergens, medications, and
environmental toxins. It is NOT purely a genetic disease - hormonal , environmental and other
unknown factors come into play .

Owners who recognize these signs of MMM in their dogs should seek veterinary care:

1) Inability to open the jaw.
2) Jaw pain.
3) Swelling or atrophy of the jaw muscle.
4) Difficulty in eating or drinking.
5) Reluctance to play with toys.
6) Sunken or protruding eyes.

If the disease is diagnosed early and a dog is treated appropriately the prognosis is good for
dogs with MMM.

Regarding breeding recommendations; MMM is not considered to be a high priority disease to
target reduction. This is due to the genetic and environmental complexities, the low incidence of
the disease, the overall good outcome with appropriate therapy and, importantly, the concern for
maintaining as much genetic diversity in the breed.



A Question of Health by Alexandra Witmond

Since I have been the Breed Health Representative, it has been matters of skin conditions, diet and behavioural problems but since March 2012 a genetic condition has come to light that affects Welsh Terriers. It’s called Primary Lens Luxation or PLL.

This condition is caused by an inherited mutation in a gene which is required for the healthy construction of the lens fibres. PLL is an inherited eye disease which can lead to blindness. In affected dogs, the tiny fibres which hold the lens break down and the lens can fall out of position which may cause glaucoma and blindness. This is a late onset condition – an affected dog would develop signs of PLL between 4 to 8 years of age.

Thankfully, there is a test for identification of the DNA mutation which has only been available since 2009. This test is useful for those breeders, or pet owners who want to breed, to identify the status of their breeding stock, so that they are not breeding from affected animals as affected dogs should not be bred from.

There can be three results–

• CLEAR – free of the PLL mutation
• CARRIER – has one copy of the mutation
• AFFECTED – has two copies of the mutation

As we have a small gene pool in Welsh Terriers, CARRIERS can be used for breeding but only to CLEAR animals, then the pups should be tested; CARRIERS X CLEAR = 50% CARRIER / 50% CLEAR.


The Kennel club have announced that, from 29th August 2013, testing results which qualify for the Kennel Club's DNA Screening Schemes will now be accepted from Animal DNA Diagnostics Ltd who carry out this PLL screening, and will be posted on the Kennel Club website. Future results will routinely be forwarded without the need for owners to contact the Kennel Club.


Customers who have already had testing performed which qualifies for the DNA Screening Schemes are invited to send a photocopy of their certificate to the Kennel Club (Health and Breeder Services, 1-5 Clarges Street, Piccadilly, London, W1J 8AB) or a scan of their certificate to

This test is not yet a requirement of the Kennel Club, but a lot of breeders having been doing the test to their stock on a voluntary basis. I am doing research as to how many dogs are affected/carriers/clear.

Anyone who would like further information, please email me at, or if you would like to get the kit to do this simple swab test, then email Dr June Swinbourne at quoting Breed296 to get a 5% discount.


Update April 2015

You may have seen, in our ‘Breed Health’ section, information on a genetic condition called Primary Lens Luxation. We have now had feedback from the organisation mentioned in that article that carries out the screening. In the year that this service has been available, they have performed 52 tests – of which 32  (62 %) are clear, 18 (34%) are carriers and just 2 (4%) are affected.