Affected gene: ARSB  
Inheritance: Autosomal recessive  
Mutations:  
- Severe form: A1 g.145138869A>G c.1427T>C p.(L476P)  
- Mild form: A1 g.145138738C>T c.1558G>A  
OMIA link: 000666-9685  

Breeds appropriate for testing:  
Domestic Shorthair, Birman, Oriental Longhair, Oriental Shorthair, Ragdoll, Siamese and related breeds  

Symptoms:  
Cats homozygous for the severe mutation (L476P) develop severe skeletal disease, corneal clouding, thickened heart valves, and prominent cytoplasmic granules in white blood cells. Cats homozygous for the mild mutation (D520N) do not develop severe symptoms but have prominent cytoplasmic granules in white blood cells. Symptoms of the disease can include growth retardation, broad faces with shortened noses, reduced flexibility, and degenerative joint disease. Although affected cats accumulate gangliosides and unesterified cholesterol in neurons, they do not exhibit notable neurological deficits.

References:  
- Lyons, L.A., Grahn, R.A., Genova, F., Beccaglia, M., Hopwood, J.J., Longeri, M. (2016). Mucopolysaccharidosis VI in cats - clarification regarding genetic testing. BMC Vet Res 12:136. PubMed reference: 27370326. DOI: 10.1186/s12917-016-0764-y.  
- Crawley, A.C., Yogalingam, G., Muller, V.J., Hopwood, J.J. (1998). Two mutations within a feline mucopolysaccharidosis type VI colony cause three different clinical phenotypes. Journal of Clinical Investigation 101:109-119. PubMed reference: 9421472. DOI: 10.1172/JCI935.  
- Yogalingam, G., Litjens, T., Bielicki, J., Crawley, A.C., Muller, V., Anson, D.S., Hopwood, J.J. (1996). Feline mucopolysaccharidosis type VI - characterization of recombinant N-acetylgalactosamine 4-sulfatase and identification of a mutation causing the disease. Journal of Biological Chemistry 271:27259-27265. PubMed reference: 8910299.