What is MPS-VI?
For more info on MPS in animals please visit: MPS Army Foundation
MPS-VI stands for Mucopolysaccharidosis Type 6 (also known as Maroteaux-Lamy syndrome).
Maroteaux-Lamy syndrome takes its name from two French Doctors, Dr. Maroteaux and Dr. Lamy, who first described the condition in 1963. These doctors discovered this disorder in Miniature Pinschers before they found it affected human children as well. At this time MPS is only found in the Miniature Pinscher breed or any mix of the breed.
Mucopolysaccharides are chains of sugar molecules that the body uses to build connective tissue.
“saccharide” is a general term for a sugar molecule (think of saccharin)
“poly” means many
“muco” refers to the thick jelly-like consistency of the molecules
Mucopolysaccharidosis not just a really big word, it's a serious disorder. Puppies born afflicted with this disorder rarely survive past the age of 2, and those who survive that long have a range of medical issues. In order to be born with MPS-VI both parents must be carriers of the MPS gene.
The body is continually replacing old cells with new, and to do that, parts of the cells must be broken down and disposed of so that the new parts can be built properly. When a dog has MPS-VI, it has a deficiency of arylsulfatase B, an enzyme that breaks up the mucopolysaccharides so the body can remove them from the cells. The mucopolysaccharides that should have been removed stay in the cells and cause damage over time, as they don't allow the proper formation of new cells.
Newborn puppies may not show any sign of the disease right away, but as the cells become damaged from not being able to get rid of the old mucopolysaccharides, symptoms start to appear. It causes spinal and skeletal deformities that can result in cracked and deformed vertebrae, facial deformities and neurological issues. It is also linked to Legge-calve Perthes disease.
Affected pups can die within a few weeks, or start to gradually deform over a few weeks/months of age. Each dog may progress at different rates depending on how quickly the cells are affected.
How is the disease inherited?
We all have genes inherited from our parents which control whether we are tall, short, fair, etc. Some genes we inherit are “recessive,” that is to say we carry the gene but it does not have any effect on our development. MPS VI (Maroteaux-Lamy syndrome) is caused by a recessive gene. If an adult carrying the abnormal gene marries another carrier there will be a one in four chance with every pregnancy that the child will inherit the defective gene from each parent and will be affected with the disease. There is a two in three chance that unaffected brothers and sisters of MPS VI children will be carriers. Inbreeding could perpetuate the disorder but it is a gene mutation like any other that is passed down both maternally and paternally.
The more awareness that is raised about MPS VI the more breeders are likely to test and eradicate the disease from the breed. If every Miniature Pinscher breeder would test for this disease, it could be eliminated from the Miniature Pinscher breed completely, but sadly, few test for it.