Question

What are mucopolysaccharides? Why is the level of urine mucopolysaccharide secretion normal in I-Cell disease while it is elevated in other lysosomal storage diseases?

Answer 1

Mucopolysaccharides are long chains of sugar molecules containing amino groups. They are basically complex polysaccharides in nature, occur as components of connective tissue. They may also occur in fluids around the joints and in mucus. They are also known as glycosaminoglycans.

For diseases other than I cell disease, breakdown of mucopolysaccharides is prevented owing to the enzymatic deficiencies which causes accumulation of the same as fragments in lysosomes which are then secreted into urine. For I cell disease, breakdown of mucolipids becomes difficult due to a defective phosphotransferrase but the metabolism of mucopolysaccharides remains normal.