Mucopolysaccharidoses (MPS) diseases are genetic lysosomal diseases (LD) 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 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||α-L-Iduronidase|
|MPS I S||Scheie||α -L-Iduronidase|
|MPS I H-S||Hurler-Scheie||α -L-Iduronidase|
|MPS II||Hunter||Iduronate sulfatase|
|MPS III A||Sanfilippo A||Heparan Ν-sulfatase|
|MPS III B||Sanfilippo B||α -N-Acetylglucosaminidase|
|MPS III C||Sanfilippo C||Acetyl CoA: α -glycosaminide acetyltransferase|
|MPS III D||Sanfilippo D||N-Acetylglucosamine 6-sulfatase|
|MPS IV A||Morquio A||Galactose 6-sulfatase|
|MPS IV B||Morquio B||β-Galactosidase|
|MPS VI||Maroteaux-Lamy||(arylsulfatase B) N-Acetylgalactosamine 4-sulfatase|
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.
MPS 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 diseases in the general population is thought to be one in 25,000 births. As part of the larger family of lysosomal diseases, of which there are approximately 50 diseases, the occurrence is about 1 in every 5,000 to 7,000 births.