Feline Mucopolysaccharidosis VI (MPS VI) – mild form and severe form
The feline mucopolysaccharidosis (MPS) is a group of lysosomal storage disorders in cats that involve the deficiency of specific enzymes required for the degradation of glycosaminoglycans (GAG). Feline mucopolysaccharidosis VI is characterized by a deficiency of N-acetylgalactosamine 4-sulfatase (4S), which leads to the lysosomal accumulation and urinary excretion of the GAG dermatan sulfate (DS) (1). The severe MPS VI phenotype is characterized by growth retardation, coarse facial features, joint stiffness, corneal clouding, skeletal deformities, and organ and soft tissue involvement in cats. As a result of DS storage in the heart valve and lung, the normal function of these organs is often compromised, leading to early death in affected individuals. The central nervous system does not appear to be affected, even in individuals with clinically severe MPS VI. Currently, there is no safe and effective treatment available for MPS patients other than surgical intervention to alleviate symptoms whenever possible.
Yogalingam, G., Hopwood, J.J., Crawley, A., and Anson, D.S. (1998). Mild feline mucopolysaccharidosis type VI. Identification of an N-acetylgalactosamine-4-sulfatase mutation causing instability and increased specific activity. J. Biol. Chem. 273, 13421–13429.