Frequently Asked Questions - MPS IIIB

What is Mucopolysaccharidosis type IIIB (MPS IIIB)?
What are the symptoms of MPS IIIB?
How is MPS IIIB inherited?
Is there a DNA test and, if so, what do the DNA test results mean?
How do I go about getting my dog tested?
Who receives notification of the DNA test results?
How common is this disease and how long has it been in the Schipperke breed?
If the mutation is so old, why has this not been seen before?
Who should have their animals tested?
When can I test my dog and how much does testing cost?
How soon can I expect to get results back?
What do I do if I have pups waiting to go to homes?
Do you provide “rush” testing on samples, bulk prices or special litter prices?
What samples is the test run on?
Other Questions

What is Mucopolysaccharidosis type IIIB (MPS IIIB)?
The disease MPS IIIB, also known as Sanfilippo syndrome type IIIB, is an inherited disease classified as a lysosomal storage disease (LSD). Lysosomes are “bags” within cells of the body and are filled with special enzymes that disassemble molecules in an orderly manner. If one of the enzymes is missing (due to mutations in the gene for that enzyme), the disassembly stops and undegraded molecules accumulate in the lysosomes (hence the term LSD). When this happens the cells become sick or die, which leads to disease. The compound accumulating in MPS IIIB is heparan sulfate and the affected enzyme is N-acetyl-a-D-glucoseaminidase (NAGLU).

What are the symptoms of MPS IIIB?
Clinical signs in the dogs are related to brain disease, appear between 2-4 years of age, and include tremor and difficulty in balancing, walking, and negotiating obstacles such as stairs. The disease is progressive and there is no effective treatment. Because of this, most owners choose euthanasia 1-2 years after recognizing clinical signs.

How is MPS IIIB inherited?
The inheritance pattern of MPS IIIB is autosomal recessive. Both males and females are equally capable of having the disease, or of being carriers. Carriers are absolutely normal, and will not have signs of the disease.

Is there a DNA test and, if so, what do the DNA test results mean?
We have a mutation-based test for the NAGLU mutation in the Schipperke breed. Testing offered at the University of Pennsylvania reports a result of “affected,” “carrier,” or “normal.”

How do I go about getting my dog tested?
See the submission form with attached instructions and check list.

Who receives notification of the DNA test results?
Results are confidential and are released only to the individual who submitted the sample.

How common is this disease and how long has it been in the Schipperke breed?
The mutant gene may be as far back as eleven generations, and hence may be very broadly distributed in the Schipperke population. The carrier frequency is unknown, but judging from similar diseases in cattle, it may be as high as 15%.

If the mutation is so old, why has this not been seen before?
Probably this disease has been seen before, but was not recognized. Factors contributing to this include a low frequency of cases, non-specific clinical signs, adult onset of signs, a lack of post-mortem examinations, and very limited knowledge among medical professionals.

Who should have their animals tested?
Every breeding animal should be DNA tested for this disease. All pups that are waiting to be placed in permanent homes should be considered for testing, to spare their new owners a great deal of anguish and anxiety.

When can I test my dog and how much does testing cost?
Testing begins April 1, 2003, and costs $75/dog. A price of $50/dog is in effect until June 1, 2003.

How soon can I expect to get results back?
Results will be available 4 weeks from the time of receipt of samples.

What do I do if I have pups waiting to go to homes?
Priority testing to ensure that pups waiting for placement are not affected will be made. See the details below.

Do you provide “rush” testing on samples, bulk prices or special litter prices?
Rush testing is not available. There are also no bulk submission or litter submission price adjustments.

What samples is the test run on?
The test can be run on either 1-2 ml of EDTA blood (purple top tube) or on cheek swabs.


Questions:
Please submit any questions you may have regarding MPS IIIB in Schipperkes to the Josephine Deubler Genetic Disease Testing Laboratory, 3900 Delancey Street, Philadelphia, PA 19104-6010 or e-mail Penngen@vet.upenn.edu. Such questions will be helpful in adding to our frequently asked questions resource.