Susceptibility to Pug Dog Encephalitis (PDE)
Introduction
Approximately
1.2% of Pug dogs die of necrotizing meningoencephalitis (NME), also known as Pug dog encephalitis (PDE). NME is an inflammatory
disease of the central nervous system that is usually progressive and fatal. Symptoms of NME include seizures, depression,
ataxia, abnormal gait and blindness (1). Female, fawn-colored Pug Dogs younger than 7 years of age are more apt
to develop NME than older, male and non-fawn colored individuals (2). Recent research has revealed that susceptibility to
NME is associated with the dog leukocyte antigen (DLA) region of dog chromosome 12 (3). The association is at or near
the region containing the DLA class II genes. Dogs that have two identical copies of the NME associated markers in this
region, have an observed risk (OR) of 12.75 for NME in their lifetime over Pugs that have only one or no copies of these markers
(OR 0-1.08).
ORDER TEST KITS - Allow 5-10 business days for test results.
Results reported as:
N/N - No copies of the NME associated markers (homozygous for normal). These dogs
have a low risk of developing NME.
N/S
- One copy of the NME associated markers (heterozygous for susceptibility). These dogs have a low risk of developing
NME.
S/S -
Two copies of the NME susceptibility associated markers. These dogs are 12.75 times more likely to develop NME
in their lifetime.
Outcomes of matings based
on NME test results:
Detailed
Information
1. N/N x N/N = all puppies will have
two copies of the low NME risk markers (N/N) and will have a significantly reduced risk of developing NME during their lifetime.
2. N/N x N/S = One half of the puppies will have two copies of the
low NME risk markers (N/N), and have a significantly reduced risk of developing NME during their lifetimes. One half of the
puppies will carry one copy of the susceptibility markers (N/S), but will also be at low risk for developing NME.
3. N/S x N/S = One fourth of puppies will be N/N
and at low risk for NME; one half will be N/S, carry the susceptibility marker, but will also be at low risk for NME;
one fourth will be S/S and will be at high risk for NME.
4.
N/S x S/S = One half of the puppies will carry the susceptibility marker (N/S), but will not be at increased risk of NME;
one half of the puppies will have two copies (S/S) of the susceptibility marker and be at high risk of NME.
5. N/N x S/S = All of the puppies will carry one copy of the susceptibility
markers (N/S), and be at low risk for developing NME.
6.
S/S x S/S = All of the puppies will carry two copies of the susceptibility marker (S/S) and be at high risk for NME.
Notes: This is not a diagnostic test for NME in Pug Dogs or for NME disease
or risk in other breeds. The test is only to determine risk for developing NME in Pug Dogs and for selecting matings
that will produce puppies that are at decreased risk (N/N, N/S). Although a significant proportion (11%) of Pug Dogs
is S/S, only about 1 in 8 of this group will develop NME during their lifetime.
Also, breeders are advised against breeding out the S genotype, because 40% of Pug
Dogs have the S genotype in a heterozygous (N/S = 29%) or homozygous state (S/S = 11%). Eliminating the S genotype will
lead to a considerable loss of genetic diversity. Therefore, breeders should carefully select matings that do not produce
S/S puppies.
The NME report includes
DNA types for a panel of 8 markers selected from the International Society of Animal Genetics (ISAG) canine parentage panel.
These markers provide individual identification for each sample tested.
References:
1. Talarico LR, Schatzberg SJ. Idiopathic
granulomatous and necrotising inflammatory disorders of the canine central nervous system: a review and future perspectives.
J Small Anim Pract 2010: 51: 138–149.
2. Levine JM, Fosgate GT, Porter B et al. Epidemiology of necrotizing meningoencephalitis in Pug dogs. J Vet
Intern Med 2008: 22: 961–968.
3.
Greer KA, AK Wong, H Liu, TR Famula, NC Pedersen, A Ruhe, M Wallace and MW Neff. Necrotizing meningoencephalitis of Pug Dogs
associates with dog leukocyte antigen class II and resembles acute variant forms of multiple sclerosis. Tissue Antigens
2010: 76:110-118.