“We now have medical data for 242 Leonbergers and DNA for 150 of those individuals. At this time we have a ratio of 3-1 of affected males to females. We have tested 98 X-chromosome markers and so far none are significantly associated with the disease. Many dogs show signs of the disease by 3 years of age, however, we have now a number of dogs previously indicated as being unaffected with a change to a diagnosis of affected, because in some dogs the signs do not first occur until after 6 years of age. We now have 7 confirmed cases and 4 possible cases where there were no signs of the disease until after 6 years of age.

Due to the change in diagnosis for a number of dogs, we are now re-analyzing the data with the new diagnostic information for x-linked recessive inheritance and since more females have now been detected, we are also analyzing for x-linked dominant inheritance. In addition we are going to test 2-3 markers nears genes that have been documented for Charcot-Marie-Tooth disease in people that are not on the dog X chromosome. We anticipate finishing this analysis (X chromosome plus 5-10 additional areas) by the end of the year. We have enough internal funds to finish this analysis. If this planned analysis does not find an associated marker, the next step will be a whole genome scan (testing 300-400 markers spread out on all 38 dog chromosomes). There is some evidence that estrogen has a protective effect on myelin which could possibly explain the gene potentially being on an autosome (not a sex chromosome) and still having more affected males than females. The cost of a whole genome scan would be in the range of $30,000-50,000 and we would plan on submitting a funding proposal to the Canine Health Foundation or the Morris Animal Foundation in late 2006 or early 2007 if necessary. If the current analysis finds a linked (associated) marker we would develop a screening marker test and start to try to sequence the actual gene.

More samples from affected dogs and related non affected are needed to confirm any positive findings and to add power to the study. We continue to collaborate with Dr. Diane Shelton for the diagnosis and we thank everyone for their participation and response to our renewed efforts at getting more DNA samples and medical information."

Midge writes:

"Thanks so much to all that have coordinated blood testing sessions throughout the country, many not without teething problems with postage etc. Hopefully I now have all relevant forms and packaging to make life a little easier. Just contact me if you need them. The researchers have been overwhelmed by the response from the UK. Sending blood works, to them is very important but knowing beyond any doubts if your dog has the disease and not something similar is critical to a true pedigree analysis. The only way to do this is by a biopsy. Maybe that could be the legacy your dog could leave to our breed but a very emotive thought when the time comes."

Inherited Leonberger Polyneuropathy

Inherited Leonberger Polyneuropathy (ILP) is a distinct syndrome not to be confused with neuropathies caused by a number of other diseases such as diabetes, lymes disease or hypothyroidism. It is an inherited degenerative disease of the peripheral nervous system, NOT the central nervous system which causes diseases such as degenerative myeolopathy.  ILP is an emerging inherited disease in the Leonberger and has only been recognised in the UK over the last four or five years with dogs affected and diagnosed more frequently than bitches. The age of diagnosed dogs and bitches varies from as young as seven months to dogs in their older years. This is not an old age illness. The severity of the disease varies in each case with milder, later onset leos in the same litter as more severe, early onset Leos. Some even are symptomless. Dogs /bitches with the older onset variation of the disease have produced early and severe onset in their offspring as well as older and less severe onset.

The onset of the condition can be slow and easily missed until the clinical signs are severe although now there is more awareness among owners and breeders making earlier diagnosis easier.

Some symptoms to look for are, any form of Laryngeal paralysis which could cause, change in bark, exercise intolerance, lack of endurance when playing, loud breathing, change in breathing, rasping, coughing after drinking or eating, clearing throat, tremors, knuckling under or dragging foot, toenails worn short on feet., raising knee high when walking. This may not be as noticeable when gaiting., awkwardness and stumbling, and bad movement. Please be aware that any of these signs may not always be associated with this illness. A dog may have Laryngeal Paralysis that can be treated by a specialist and not have Polyneuropathy, the same as a dog can have Polyneuropathy without having Laryngeal Paralysis.

In order to have a definite diagnosis of ILP you have to eliminate neuropathies caused by untreated chronic hypothyroidism and other neuro-muscular diseases as well as neoplasia (cancers)

Testing on dogs could include simple tests by a neurologist, EMG and NCV testing and more positively the most definitive nerve and muscle biopsy. The results of this if negative will only mean that your dog doesn’t have the disease at that present time. He/she could still be a carrier.

Unfortunately the mode of inheritance is not yet known although studies in USA hope to find a DNA basis for a genetic marker. Until then we cannot stop the disease spreading, affected dogs will need a lot of tender loving care whilst they remain happy and pain free, until their quality of life deteriorates or they become immobile., losing use of their limbs.

It is for breeders, owners and vets to identify the disease and hopefully try and eradicate it before it becomes even more widespread in the Leonberger community here in the Uk.