| Dermatamyositis (DM) |
Dermatamyositis is an inflammation of the skin and the muscles. DM is not demodectic mange or
any other disorder. This disease may affect both the skin and the underlying muscles.
The degree that the dog is affected varies a great deal.
The skin is usually affected before the muscles. Some dogs are affected so little that it is not
even noticed. Dermatamyositis most often shows up by six months of age and some mildly affected
dogs may outgrow this condition by a year old. Some dogs have such severe muscle atrophy that
they must be euthanized. Severely affected dogs may have the leg muscles or the muscles used
for eating affected, making the dog's life very difficult and uncomfortable.
Symptoms are red skin, blisters, crusty skin, and hair loss of the ear tips, face, around the eyes
tip of the tail, elbows and toes and legs. The skin may become scarred and hairless. The hair may
regrow. Your vet must do a biopsy of the skin and muscle to verify this condition since other
conditions have similar symptoms. A biopsy is the only way to diagnose DM. Texax A & M
University is doing research at this time for a DNA test.
Treatment may be avoiding sunshine and using suncreens for mildly affected dogs, or using
cortisteroids and vitamin E during flare ups of moderately affected dogs. Very severely affected
dogs may need to be euthanized since it is difficult for them to lead a normal life.
Breeds that are affected with this disease: Shetland Sheepdogs, Australian Cattle Dogs, Chow
Chow, Kusasz, Pembrooke Welsh Corgi, German Shepherd Dog, Collie and mixes of these.
Dogs with this condtion should not be bred at all, since this disease can severely affect the dog's
life if it has the most severe form of dermatamyositis. The mode of inheritance is autosomal
dominant. This means that even though all the puppies in a litter could have the genes for
dermatamyositis, the way that it is expressed (shows up) within that litter may vary from so mild you
aren't aware of it, to so severe that the dog is not capable of functioning or living well. Some dogs
will not carry the gene for dermatamyositis, some will carry one gene, but appear normal & pass it
on, and some dogs will carry two genes and express (show) the disease and pass it along to their
young.
The chart below will help show how this disease is inherited.
any other disorder. This disease may affect both the skin and the underlying muscles.
The degree that the dog is affected varies a great deal.
The skin is usually affected before the muscles. Some dogs are affected so little that it is not
even noticed. Dermatamyositis most often shows up by six months of age and some mildly affected
dogs may outgrow this condition by a year old. Some dogs have such severe muscle atrophy that
they must be euthanized. Severely affected dogs may have the leg muscles or the muscles used
for eating affected, making the dog's life very difficult and uncomfortable.
Symptoms are red skin, blisters, crusty skin, and hair loss of the ear tips, face, around the eyes
tip of the tail, elbows and toes and legs. The skin may become scarred and hairless. The hair may
regrow. Your vet must do a biopsy of the skin and muscle to verify this condition since other
conditions have similar symptoms. A biopsy is the only way to diagnose DM. Texax A & M
University is doing research at this time for a DNA test.
Treatment may be avoiding sunshine and using suncreens for mildly affected dogs, or using
cortisteroids and vitamin E during flare ups of moderately affected dogs. Very severely affected
dogs may need to be euthanized since it is difficult for them to lead a normal life.
Breeds that are affected with this disease: Shetland Sheepdogs, Australian Cattle Dogs, Chow
Chow, Kusasz, Pembrooke Welsh Corgi, German Shepherd Dog, Collie and mixes of these.
Dogs with this condtion should not be bred at all, since this disease can severely affect the dog's
life if it has the most severe form of dermatamyositis. The mode of inheritance is autosomal
dominant. This means that even though all the puppies in a litter could have the genes for
dermatamyositis, the way that it is expressed (shows up) within that litter may vary from so mild you
aren't aware of it, to so severe that the dog is not capable of functioning or living well. Some dogs
will not carry the gene for dermatamyositis, some will carry one gene, but appear normal & pass it
on, and some dogs will carry two genes and express (show) the disease and pass it along to their
young.
The chart below will help show how this disease is inherited.
| SIRE NORMAL (DD) (no genes for dermatamyositis) |
| DAM NORMAL (DD) (no genes for dermatamyositis) |
| SIRE Normal/carrier (Dd) (carries one gene for this diesease) |
| None of the dogs above will have dermatamyositis, nor will they pass this disease on to their offspring. |
| DAM Normal/carrier (Dd) (carries one gene for this diesease) |
| These puppies has 2 affected genes & will have the disease and will also pass it on to all of their offspring.. |
| All PUPPIES from these two parents will be NORMAL (no genes for dermatamyositis at all) |
| Some puppies will inherit 1 affected gene & 1 normal gene. These puppies will not be affected with the disease themselves, but can pass on the disease to some of their offspring because they do have the gene for the disease. |
| Some puppies will get 2 normal genes. (One from each parent) These puppies will not have the disease and will not pass it on. |
| SIRE Normal/carrier (Dd) (carries one gene for this disease) |
| DAM NORMAL (DD) (no genes for dermatamyositis) |
| DD |
| Dd |
| Dd |
| dd |
| Sire's genes |
| Dam's genes |
These are the possible
combinations of genes that the
puppies might inherit.
1/4 would be Normal/Normal *
1/4 would be affected/affected
1/2 would be Normal/affected
combinations of genes that the
puppies might inherit.
1/4 would be Normal/Normal *
1/4 would be affected/affected
1/2 would be Normal/affected
* This is the expected combination of genetic possiblities. The way the
genes are inherited is random, and you may get an entire litter of puppies
that are affected/carrier or Normal/affected or Normal/Normal. So, even
though we expect the numbers of puppies to relate to this chart, the
percentages are not exact for each litter.
genes are inherited is random, and you may get an entire litter of puppies
that are affected/carrier or Normal/affected or Normal/Normal. So, even
though we expect the numbers of puppies to relate to this chart, the
percentages are not exact for each litter.
| Sire's genes |
| Dam's genes |
| DD |
| DD |
| DD |
| DD |
| These puppies could only inherit the normal genes (one from each parent) because the parents only have normal genes to pass along. 100% of the puppies would be Normal/Normal. |
| Sire's genes |
| Dam's genes |
| DD |
| Dd |
| DD |
| Dd |
| Some puppies will get 2 normal genes. (One from each parent) These puppies will not have the disease and will not pass it on. |
| Some puppies will inherit 1 affected gene & 1 normal gene. These puppies will not be affected with the disease themselves, but can pass on the disease to some of its offspring because they do have the gene for the disease. |
These are the possible combinations of genes that the puppies might inherit.
1/2 would be Normal/Normal
1/2 would be Normal/affected
1/2 would be Normal/Normal
1/2 would be Normal/affected
| SIRE Affected/carrier (dd) (carries two genes for this disease) |
| DAM NORMAL (DD) (no genes for dermatamyositis) |
| ALL of these puppies will inherit 1 affected gene & 1 normal gene. These puppies will not be affected with the disease themselves, but can pass on the disease to some of its offspring because they do have the gene for the disease. |
| D |
| d |
| D |
| d |
| D |
| D |
| D |
| D |
| D |
| d |
| d |
| d |
| D |
| D |
| D |
| D |
| Dam's genes |
| Sire's genes |
| Dd |
| Dd |
| Dd |
| Dd |
All these puppies will inherit the one normal gene and one affected gene. The sire could only pass on an
affected gene, and the dam could only pass on a normal gene because those are the only genes they have
to pass along. 100% of the puppies would be Normal/carriers.
affected gene, and the dam could only pass on a normal gene because those are the only genes they have
to pass along. 100% of the puppies would be Normal/carriers.
| SIRE Affected/carrier (dd) (carries two genes for this disease) |
| DAM Affected/carrier (dd) (carries two genes for this disease) |
| ALL of these puppies will inherit 2 affected genes. These puppies will affected with the disease themselves, and will pass on the disease to all of its offspring because they have the only affected genes to pass on. |
| d |
| d |
| d |
| d |
| Dam's genes |
| Sire's genes |
| . |
| . |
| . |
| . |
Here I have left the puppies' genetic results blank, so you can try it for
yourself. Move the sire's left-hand gene down into the top left box & the
dam's top gene over, into the top left box.
Next move the sire's left-hand gene into the bottom left box, and the
dam's bottom gene into to bottom left box. Each box should have two
genes in it - one from the sire, one from the dam.
Continue on by moving the sire's right-hand gene to the top right box,
and also to the bottom right box. Move the dam's top gene to the top
right box, and her bottom gene to the bottom right box. Again, each box
will have two gene's in them, one from dad, one from mom.
This is the way breeders figure out what genetic possibilities we may
get when we do a breeding.
(Click here for the results.)
yourself. Move the sire's left-hand gene down into the top left box & the
dam's top gene over, into the top left box.
Next move the sire's left-hand gene into the bottom left box, and the
dam's bottom gene into to bottom left box. Each box should have two
genes in it - one from the sire, one from the dam.
Continue on by moving the sire's right-hand gene to the top right box,
and also to the bottom right box. Move the dam's top gene to the top
right box, and her bottom gene to the bottom right box. Again, each box
will have two gene's in them, one from dad, one from mom.
This is the way breeders figure out what genetic possibilities we may
get when we do a breeding.
(Click here for the results.)
| Try it yourself! |