Fucosidosis, also called alpha-l-fucosidase deficiency, is a rare autosomal recessive lysosomal storage disease

Lysosomal storage disease

Lysosomal storage diseases are a group of approximately 50 rare inherited metabolic disorders that result from defects in lysosomal function...

 in which the enzyme

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 fucosidase

Fucosidase

Tissue alpha-L-fucosidase is an enzyme that in humans is encoded by the FUCA1 gene.Alpha-Fucosidase is an enzyme that breaks down fucose.-External links:...

 is not properly used in the cells to break down fucose

Fucose

Fucose is a hexose deoxy sugar with the chemical formula C6H12O5. It is found on N-linked glycans on the mammalian, insect and plant cell surface, and is the fundamental sub-unit of the fucoidan polysaccharide...

. This enzyme normally cleaves long sugar chains known as oligosaccharides in the lysosome. When the enzyme is absent, sugar chains accumulate and eventually lead to the clinical features of fucosidosis. The symptoms of this disorder may progress in degrees of severity over time.

Focosidosis is one of nine identified glycoprotein storage diseases. The gene encoding the alpha-fucosidase, FUCA 1, was found to be located to the short arm of chromosome 1, by Carrit and co-workers, in 1982.

Types

There are two different types of fucosidosis, Type I and Type II, characterized by the age of onset and by the types of physical and mental manifestations of the disorder.

• Type I typically appears in the first three to 18 months of life. Symptoms include coarsening of facial features, a large liver, spleen and/or heart, and abnormal bone deformities. Cherry red spots may be present on the surface of the eye. Mental retardation and seizures are also present. Patients have no vascular lesions, but have rapid psychomotor regression, severe and rapidly progressing neurologic signs, elevated sodium and chloride excretion in the sweat, and fatal outcome before the sixth year.

• Type II patients have angiokeratoma
  Angiokeratoma
  Angiokeratoma a is benign cutaneous lesion of capillaries, resulting in small marks of red to blue color and characterized by hyperkeratosis....
  
  , milder psychomotor retardation and neurologic signs, longer survival, and normal salinity in the sweat. The disease often appears between 12 and 24 months of life. Affected children usually have mild coarsening of facial features, abnormal bone deformities, mental retardation, and an enlarged liver, spleen and/or heart. Twisted blood vessels within the membrane covering of the eye and inner eyelid are characteristic features of Type II Fucosidosis.

External links

• Hide and Seek Foundation For Lysosomal Disease Research
• International Advocate For Glycoprotein Storage Diseases
• Lysosomal Learning site