Glycoproteinosis
Oligosaccharidoses referred to in some publications as glycoproteinoses or Glycoproteinosen, are a group of extremely rare autosomal recessive lysosomal storage diseases. The phenotype of these patients is similar to the mucopolysaccharidoses. However, etiology and symptoms are different. In the Anglo-Saxon literature, the term is used for the Glycoproteinosis oligosaccharidoses most.
The oligosaccharidoses
So far the following oligosaccharidoses are known:
- α - mannosidosis
- β - mannosidosis
- Fucosidosis
- Aspartylglukosaminurie
- Schindler disease type I
- Galactosialidosis ( Goldberg syndrome)
- Sialic acid storage disease infantile ( ISSD )
- Sialic acid storage disease adult ( Salla disease)
Etiology
The cause of oligosaccharidoses mutations in the genome coding for specific enzymes. This leads to malfunctions in the metabolism of glycosylated proteins ( glycoproteins ), such as membrane or structural proteins. These glycoproteins can not be degraded by the loss of activity of the enzymes. Depending on the affected enzyme, different products accumulate intracellularly. This leads to similar, but different in the course and in the phenotype, clinical pictures.
In the case of sialic acid storage disease, however, is a loss of activity of an anion transporter sialic acid ausschleust from the lysosome through the lysosomal membrane, the cause of the disease.
The oligosaccharidoses be inherited as an autosomal recessive trait.
Symptoms
Oligosaccharidoses are usually already symptomatic newborns. Coarse facial features, skeletal dystrophies, short stature, neurodegenerative diseases and enlargements of the liver and spleen ( hepatosplenomegaly ) are the most common symptoms. The disorders are more progressive.
Diagnostics
About the increased concentration of oligosaccharides in the urine and the determination of the enzymatic activity can diagnose the oligosaccharidoses. A molecular-biological diagnostics ( DNA analysis), is possible.
Therapy
There are so far no known causal therapies for oligosaccharidoses. Treatment is usually symptomatic. Enzyme replacement therapy ( ERT) are currently being tested or in development. For oligosaccharidoses there are no approved ERT. The regional or even in the field of basic research, gene therapy could in the future allow for healing in oligosaccharidoses.