Breeds Affected: Brazilian Terrier
Samples Accepted: Blood, Buccal Swab
Disease Information: Mucopolysaccharidosis Type VII is a lysosomal storage disease. Affected pups show skeletal changes and dwarfism, along with severe growth retardation and spontaneous death. Symptoms are apparent at or shortly after birth.
Inheritance Information: MPS VII is autosomal recessive, meaning that animals with two copies of this allele will be affected. Animals with one copy of the gene will be clinically-normal carriers.
The possible genotypes are:
N/N The dog is normal, and cannot produce affected offspring.
N/mps7 The dog is a carrier, and can pass the allele on to approximately 50% of any offspring. If bred to another N/mps7 carrier, approximately 25% of the offspring will be normal, 50% will be carriers, and 25% will be affected.
mps7/mps7 The dog is affected. If bred to a normal animal, 100% of the offspring will be carriers. If bred to an N/mps7 carrier, 50% of the offspring will be carriers and 50% will be affected.
– Carriers may be bred to normal animals (N/mps7 x N/N) without any risk of producing affected offspring. The offspring should be tested before breeding to determine if they are carriers or normal.
– Breeding two carriers (N/mps7 x N/mps7) is not recommended due to the possibility of 25% of the offspring being affected.
– Affected animals (mps7/mps7) should not be used for breeding.
Test information: This mutation test identifies a single base change in the GUSB gene.
Hytönen, M.K., Arumilli, M., Lappalainen, A.K., Kallio, H., Snellman, M., Sainio, K., Lohi, H.: A novel GUSB mutation in Brazilian terriers with severe skeletal abnormalities defines the disease as mucopolysaccharidosis VII. PLoS One 7:e40281, 2012. Pubmed reference: 22815736. DOI: 10.1371/journal.pone.0040281.
Further information is available at the Online Mendelian Inheritance in Animals website.