What Are MPS and Related Diseases?Mucopolysaccharidoses (MPS) and related diseases are genetic lysosomal storage diseases (LSD) caused by the body’s inability to produce specific enzymes. Normally, the body uses enzymes to break down and recycle materials in cells. In individuals with MPS and related diseases, the missing or insufficient enzyme prevents the proper recycling process, resulting in the storage of materials in virtually every cell of the body. As a result, cells do not perform properly and may cause progressive damage throughout the body, including the heart, bones, joints, respiratory system and central nervous system. While the disease may not be apparent at birth, signs and symptoms develop with age as more cells become damaged by the accumulation of cell materials.
Syndrome Name Common Name Enzyme Deficiency
MPS I H Hurler a-L-Iduronidase
MPS I S Scheie a-L-Iduronidase
MPS I H-S Hurler-Scheie a-L-Iduronidase
MPS II Hunter Iduronate sulfatase
MPS III A Sanfilippo A Heparan N-sulfatase
MPS III B Sanfilippo B a-N-Acetylglucosaminidase
MPS III C Sanfilippo C Acetyl CoA: a-glycosaminide acetyltransferase
MPS III D Sanfilippo D N-Acetylglucosamine 6-sulfatase
MPS IV A Morquio A Galactose 6-sulfatase
MPS IV B Morquio B B-Galactosidase
MPS VI Maroteaux-Lamy(arylsulfatase B) N-Acetylgalactosamine 4-sulfatase
MPS VII Sly B-Glucuronidase
MPS IX Hyaluronidase
ML II I-Cell N-acetylglucosamine-1-phosphotransferase
ML III Psuedo-Hurler polydystrophy N-acetylglucosamine-1-phosphotransferase
What are the Major Characteristics Of MPS and Related Diseases?
While the symptoms of the diseases may vary from one syndrome to another, there are similarities. Affected individuals may have mental retardation, cloudy corneas, short stature, stiff joints, incontinence, speech and hearing impairment, chronic runny nose, hernia, heart disease, hyperactivity, depression, pain and a dramatically shortened life span.
How Are These Diseases Inherited?
MPS and related diseases are hereditary. In nearly all cases a child receives a recessive gene from each parent. MPS II is the only exception where the gene may be passed from a mother to her male children. A couple’s chance of having another child with one of these diseases is 1 in 4 with each pregnancy. Unaffected siblings may be gene carriers of the disease. The occurrence of MPS and related diseases in the general population is thought to be one in 25,000 births.