Definition of Mucolipidosis

Mucolipidosis: One of a group of inherited storage diseases in which both lipids and substances called mucopolysaccharides accumulate in the tissues of the body.

Four mucolipidosis have been identified:

• Mucolipidosis I: due to deficiency of the enzyme muramidase.
• Mucolipidosis II: due to deficiency of the enzyme UDP-N-acetylglucosamine-lysosomal-enzyme N-acetylglucosamine-phosphotransferase. Mucolipidosis II is also called I-cell disease.
• Mucolipidosis III: due to deficiency of the enzyme N-acetylglucosamine-1-phosphotransferase. Mucolipidosis III is also called pseudo-Hurler polydystrophy.
• Mucolipidosis IV: due to mutation in the gene encoding mucolipin-1. Mucolipidosis IV is also called sialolipidosis.

All four of the mucolipidoses are lysosomal disorders -- the lysomes are organelles within the cell containing enzymes that can digest (lyse) substances -- and all are inherited in an autosomal recessive manner.