Sialidosis a genetic disease, which is a rare inherited metabolic disorder that is characterized by a deficiency of the enzyme neuraminidase. Deficiency is manifested through the excessive accumulation of toxic materials in the body.
- Type I – most often manifesting in the second decade of life, it is associated with the development of rapid, involuntary muscle contractions, as well as the appearance of the characteristic cherry-red spots in the eyes. In the case of this type of sialidosis, there can be other neurological problems.
- Type II is the heavier form of sialidosis and begins in infancy or later in childhood. It is characterized by cherry-red spots on the skin, coarse facial features, skeletal defects, and mild cognitive impairment.
The disease is inherited as an autosomal recessive trait gene.
Causes of sialidosis
Sialidosis belongs to a group of diseases called lysosomal disorders. Lysosomes are particles in membranes within the cell, whose function is the basic operation of units digestion within cells. Lysosomal enzymes break down and affect absorption of the individual components, such as complex consisting of proteins and sugar molecules – glycoprotein.
Persons suffering sialidosis have low levels or activity of neuraminidase, which leads to an excessive build-up of noxious compounds in cells, and this, in turn, has some undesirable effects.
The symptoms of sialidosis
Age of onset, symptoms, and progress of the disease can differ significantly among individuals. It is important, however, a relatively rapid diagnosis of the disease.
Most cases of the disease are diagnosed in the second or third decade of life, and appear with symptoms of:
- trouble walking,
- vision problems – occur here in particular spots of cherry shade, which may result in the loss of clarity of vision, impaired color vision, and even blindness.
- sudden, involuntary eye movements (nystagmus), and corneal opacity,
- inability to coordinate movements and sudden involuntary muscle spasms or jerking.
- abnormal enlargement of the liver and / or spleen,
- particular bone deformities, coarse facial features, enlargement of the skull, widely spaced teeth, abnormalities in the bones of the pelvis, ribs, and others,
- the delay in achieving developmental stages and cognitive disorders.
- in infants with congenital sialidosis may develop fetal changed tumor edema, ascites, and other life-threatening complications.
Diagnosis and treatment of sialidosis
The diagnosis is based on an identification of characteristic symptoms, a detailed medical history, a thorough clinical assessment and some individual tests. For example, a urine test may show increased levels of oligosaccharides, and blood tests reveal low levels of the enzyme alpha-neuraminidase, and the skin biopsy will reveal the diseased tissue. Can also be performed prenatal diagnosis.
Unfortunately, there is no specific treatment. It relies mainly on the prevention of specific symptoms. Are used, among other things, anticonvulsants, but are not always effective.