Affected Genes: ARSB
 Transmission: 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 Recommended 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 still present prominent cytoplasmic granules in white blood cells.
Additional symptoms may include: Growth retardation, Broad faces with shortened noses, Reduced flexibility,  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: 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: 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: 8910299