DEGENERATIVE MYELOPATHY - DM
- validated in Pugs by DNA-tests and postmortem examination of spinal cords
www.eddieswheels.com - with a link about DM
DM Degenerative Myelopathy - sometimes referred to as CDRM - exists among our Pugs and resembles the human diagnose MS - but DM-researchers have compared it to ALS, as it is caused by a missense mutation SOD1 - one DNA-base is changed to code for a different amino acid which builds a defective protein. It is a neurological disorder (and it is not caused by skeletal malformations or other).
The DM rear weakness usually shows little by little and is to start with not painful. The reflex movements slow down and typically the dog drags its hind leg paws to the ground, so that the claws are worn on the top surface. The dog does not seem to be in pain. The gait gets wobbly and the dog loses balance at sharp turns and falls down with the rear end. In the terminal phase, which may last several years, the sense of feeling is lost completely and then the dog loses control over bowel and bladder.
There is a breed disposition for DM in Pugs, but because symptoms show up late in life between the ages 5-14 years, the carriers unfortunately may have been used for breeding. Of course, two Pugs should never be mated in case both of them have close relatives showing symptoms of DM or CDRM with a progressive rear weakness or hind leg paralysis.
Now an American research team, among them the Swedish microbiogeneticist professor Kerstin Lindblad-Toh sponsored by the AKC Health Foundation and many Breed Clubs, has identified a defect gene - called A - that causes Degenerative Myelopathy in many different breeds, among others French Bulldogs and Pugs. The normal, not mutated allele of the same gene, by the research workers called G - is now called N=Normal in the OFA statistics. All dogs tested with symptoms of DM have carried the gene combination A/A and have consecuently inherited the defect gene from both parents: both the sire and the dam have been carriers of Degenertive Myelopathy. Dogs DNA-testated with the gene combination A/N have shown no apparent symptoms, and have been hidden carriers. Every dog tested with the gene combination A/A has not yet developed symptoms, but is at risk doing so with progressing age.
This defect-mutated gene can now be identified by a simple DNA-sample on a FTA-card, now for sale in the OFA webshop - click on these two banner links below for info. It is a buccal saliva sample, see photos for cells from the inside of the cheeks, which can be collected by the owner without veterinary assistance. The FTA-cards are sent to the research lab by mail in an ordinary letter.
The defect mutation in DM - Degenerative Myelopathy causes a progressive rear end weakness and hind legs paralysis, which sooner or later leads to euthanasia. This condition is called 'wobbling disease'and affects many breeds, incl. French Bulldogs and Pugs - so far 82 Pugs have been tested according to OFA's statistics. 26 of them (32%) carried this mutation from one parent A/N and could pass it on to its offspring. Four Pugs (5%) carried the mutation from both parents A/A and are "at risk" to develop symptoms with age.