MPSIIIB is short for "Mucopolysaccharidosis type IIIB" and this is a disease that affects both people and Schipperkes. The most important thing a prospective Schipperke owner can know about this disease is that it always results in death around 2 to 4 years of age for an affected dog. The second most important thing you can know is that there is a genetic test for it, so that no Schipperke ever need die of this disease. It is very, very important to get a puppy from a breeder who TESTS for this disease, and can prove to you that at least one parent of their litter is MPS normal (it is ok for a dog to be a carrier). Currently, the only facility that can run this genetic test is UPenn, and it is OK to ask breeders for proof that they have tested for this disease.
So, if you want to understand more of how it works, keep reading.
To understand how MPS works, it is important to understand just a little bit about cellular structure. Cells are like tiny little cities, with structures and components inside them to build and break down the things they need and do not need. They are surrounded by a "cell wall" which is composed of lipids (fats, which is a good water-tight seal to protect the cell) and proteins, which act as "gates" for the cell, controlling what comes in and leaves. Now, this is a very good system for the cell, but it does mean that whatever the cell needs to get rid of has to be broken down into those tiny components so it can be transferred out of the "gate".
The cell has a couple of ways of breaking down unwanted things within the cell, but one of the most important ones is an organelle known as a "lysosome". Sometimes the lysosome has been called the "trash can" of the cell, but it can also be thought of as a processing plant, which breaks down unwanted things - you can even think of it as a recycling center! There are many genes involved in creating the tools that the lysosome needs to break down unwanted things, and when a mutation occurs which causes this process to stop working or not work well, the disease is then known as a "Lysosome Disorder". Not all of these disorders result in death, but MPSIIIb does - always.
So, what are the specifics of MPSIIIb? "Our" MPS is a mutation in the gene that creates an enzyme called "NAGLU", which is the short name for "alpha-N-acetylglucosaminidase". NAGLU breaks down large sugar molecules called GAG's (mucopolysaccharides).
So, how does this work? In essence, all dogs and all people have two NAGLU genes that create this important enzyme. In people and in Schipperkes, there has been a mutation at some point that has caused the gene not to work. Instead of producing NAGLU, it produces.... nothing. Now, if you - or your dog - has one gene that produces NAGLU, and one gene that produces nothing, you still have NAGLU to break down the sugar molecules, and you are ok, you are healthy. Schipperkes that are carriers lead normal lives (our oldest dog at 14 and a half is a carrier). The problem comes in when you have two genes that have mutations, two genes that produce nothing.
So, what happens then? Well, the large sugar molecules are brought to a lysosome to be broken down, and when it gets to the point where NAGLU is needed, the lysosome has nothing and the sugar molecule remains large. So instead of exporting the broken down molecules, the lysosome keeps the sugar molecule inside the organelle. There is no immediate reaction to the health of the human or Schipperke. However, as more sugar molecules are brought in and kept in the organelle, like a "trash can" it fills up. When the trash can is full, the lysosome can no longer function at all.
So, what happens then? The cell, recognizing the issue, builds another lysosome (yes, cells can have several hundred lysosomes!). So you still do not see a health reaction in the affected person or Schipperke. Eventually, though, the new "trash can" fills with trash, and it, also, can no longer work. As time moves on, you eventually have a cell that is filling up with full trash cans, and the cell itself ceases to correctly function. If it were a matter of a single cell, you would still not have a health issue, but it is many cells within the creature and eventually this affects the over all health.
In people, symptoms of MPS can include severe neurological symptoms, including progressive dementia, aggressive behavior, hyperactivity, seizures, deafness, loss of vision, and an inability to sleep for more than a few hours at a time. In Schipperkes, it has been noted that the coat will turn very red, the dog will have tremors, difficulty in balancing, walking, and negotiating obstacles such as stairs. Most Schipperkes die between 2 and 4 years of age.
There has been a DNA test for Schipperkes offered to the public since 2003. There is no excuse for an affected dog, doomed to die, to ever be born, but it has happened. In rare cases, it has been through testing errors (since these errors are almost always made through swab testing, most reputable breeders want blood results only). A few have occurred through accidental matings, but the most have occurred since that time by casual breeders - otherwise known as backyard breeders - or puppymills, just not testing their dogs. A backyard breeder is someone who is not actively involved in the breed - they do not show their dogs in conformation shows, performance events, or anything else. They are called "backyard" breeders because their dogs never leave their backyard. While they might not be bad people and they might love their dogs very much, without being involved in the sports themselves, they are not involved in the information exchange that comes from that, they do not see dogs other than their own, and they have no drive to improve their dogs, the breed, or themselves through education. One backyard breeder (BYB) told me that MPSIIIb was a hoax and she refused to test for it. I have heard of dogs purchased at pet stores (which always come from puppymills), who were carriers for MPSIIIb, and dogs from BYB's which were carriers, and a few cases from the west to east coast of the USA, where Schipperkes were born affected with this disease. What is truly scary is that some reputable breeders, breeding a litter to preserve lines and select puppies that are not carriers for MPS, have placed their MPS carriers in pet homes on a limited registration, with a requirement to neuter. Instead of following their contract, these pet owners have (on the sly!) allowed these dogs to be used for breeding, resulting in puppies that have no AKC registration. Often these people breed puppies with no papers at all, or they get one of the fraudulent dog registrations to give them papers on the litter of puppies. (This would include APRI, ConKC (Continential Kennel Club), and others). This means that if you buy a dog from a BYB who uses alternative registrations, your chances of getting a puppy that is affected with this disease is MUCH higher! If you are paying money because a puppy is purebred, you should always demand AKC registration.
This is why it is so, so, so important for you to question your breeder before you buy a puppy and make sure that they are preserving and helping this breed instead of just breeding them randomly and profiting from the puppies they produce.
MPSIIIb has likely been in the breed since the 1950's, possibly earlier. For years, preservation breeders, who tend to pore over pedigrees, debated who the original carrier might be, and various people, including myself, have their theories. What we can say for sure is that it has been around a long time, and there is no single line you can consider safe from this disorder without that DNA test. So please, when shopping for a puppy, accept no excuses!