Mucopolysaccharidosis IIIB, Sanfilippo Syndrome Type B, MPS IIIB

Affected dogs develop a slowly progressive ataxia, typically leading to humane euthanasia before six years of age. Other signs include mental dullness, with exaggerated abnormal gait (hypermetria), truncal swaying (pulling the spine and attached tissues back and forth), and fine whole-body and head tremors.

Clinical signs may be observed at approximately two years of age.

Diagnosis is made based on clinical history, physical examination, genetic testing, and ruling out other causes of similar symptoms. Intracytoplasmic granules may be found in the white cells of peripheral blood and cerebrospinal fluid (CSF), and increased HS may be measured in plasma, CSF, and urine of affected dogs.

There is no cure for MPS IIIB; all currently available treatments are symptomatic or supportive in nature. Gene therapy and enzyme replacement therapy are evolving fields that require more research to be available clinically.

Talk to your vet about your dog’s mucopolysaccharidosis result so you can work together to plan ongoing care and monitoring.

Schedule regular checkups to monitor for changes in mobility, coordination, or behavior.

Work with your vet to provide supportive care that keeps your dog comfortable and helps them stay active and engaged.

Help your dog feel secure by keeping furniture in familiar places, using non-slip mats, and maintaining predictable daily routines.

Since the discovery of the causative variant, selective screening and breeding practices have led to a dramatic decrease in allele frequency within the Schipperke breed.

Penetrance: Mucopolysaccharidosis IIIB is recessive, that is, a dog requires two copies of the variant to show signs of the disease from the variant. This variant was first described in Schipperke.

Gene

NAGLU

Inheritance type

recessive

Clinical category

Multisystem

Citations

1. Raj et al 2020
2. Ellinwood et al 2003
3. Egeland et al 2020

• Schipperke