This disease is characterized by late onset tremors, mental dullness, ataxia, lethargy, anorexia, tremors, and behavioral changes, such as unprovoked aggression. At approximately two years of age, affected Schipperkes develop a slowly progressive ataxia leading to humane euthanasia before six years of age.
4–5 years of age
Autosomal recessive
Affected dogs may have grossly enlarged lateral ventricles and atrophied cerebellum. Histologically, severe diffuse Purkinje cell loss is present with the remaining Purkinje cells containing cytoplasmic granules that are mildly swollen. Moderate to marked, diffuse thinning of the molecular and granular layers may be present. Moderate neuronal and ependymal cell vacuolation in the spinal cord is diffuse, with severe lesions in the ventral horn.
NAGLU and XM_548088.6:c.2110_2111ins[A(40_70);2100_2110]
Explanation of Results
| Genotype |
Phenotype |
Interpretation |
| 2-2 (Homozygous Disease Variant) |
Unhealthy (Affected) |
Homozygous Affecteds (2-2) are expected to develop signs consistent with Mucopolysaccharidosis (MPS) IIIB and all of their offspring will inherit a disease variant allele. Parents, offspring and relatives should also be tested. You may choose to contact us for a consultation on the management of this disease. 1 = Normal allele; 2 = Variant allele. |
| 1-2 (Heterozygous) |
Healthy (Carrier) |
Heterozygous Carriers (1-2) are not expected to develop signs of Mucopolysaccharidosis (MPS) IIIB but each of their offspring has a chance of inheriting a disease variant allele. Parents, offspring and relatives should also be tested. 1 = Normal allele; 2 = Variant allele. |
| 1-1 (Homozygous Normal) |
Healthy (Normal, Clear) |
Homozygous Normals (1-1) are not expected to develop signs of Mucopolysaccharidosis (MPS) IIIB and none of their offspring will inherit the disease variant allele. 1 = Normal allele; 2 = Variant allele. |
Raj K, Ellinwood NM, Giger U. An exonic insertion in the NAGLU gene causing Mucopolysaccharidosis IIIB in Schipperke dogs. Sci Rep. 2020 Feb 21;10(1):3170. doi: 10.1038/s41598-020-60121-3. PMID: 32081995; PMCID: PMC7035321.
Ellinwood NM, Wang P, Skeen T, Sharp NJ, Cesta M, Decker S, Edwards NJ, Bublot I, Thompson JN, Bush W, Hardam E, Haskins ME, Giger U. A model of mucopolysaccharidosis IIIB (Sanfilippo syndrome type IIIB): N-acetyl-alpha-D-glucosaminidase deficiency in Schipperke dogs. J Inherit Metab Dis. 2003;26(5):489-504. doi: 10.1023/a:1025177411938. PMID: 14518829.
