This inherited disease is a part of a group of disorders known as the lysosomal storage diseases. This rare genetic condition is characterized by the deficiency of a certain enzyme known as alpha-L-fucosidade that are essential for the breakdown of fucose-containing glycolipids or the fucose-containing glycoproteins. This disorder can affect several parts of the body but particularly the brain and as the result, the affected individual exhibit intellectual disability with the risk of developing dementia later in life.
Causes
Fucosidosis develops as the result of a mutation in the gene FUCA1 which is important for the production of an enzyme known as alpha-L-fucosidase. The genetic mutation causes the deficiency of the alpha-L-fucosidase enzyme which affects the metabolizing process of the glycolipids and glycoproteins. As the result, these compounds accumulate and causes malfunction of the cells. This accumulation can occur in any parts of the body such as the skin, heart, liver, kidneys and causes the associated symptoms. When the brain cells are affected, it can cause the neurological symptoms. This disorder is inherited in an autosomal recessive pattern meaning both the copies of the gene in each cell are defective.
Symptoms
There are two types of fucosidosis that are characterized by the physical, mental symptoms and the age of onset. The type 1 develops during the 3-18 months of the infant’s life and presents coarsening of the facial features, abnormal bone formation, large liver, spleen and the heart. Red spots may also be evident on the retina of the eye along with mental retardation and seizures. The type 2 develops around 12- 24 months of age and presents mild coarsening of the facial features, large liver, spleen and heart, superficial blood vessel dilation, abnormal bone development and mental retardation. In addition, the affected individuals also have twisted blood vessels of the membranes that cover the inner eyelid.
Diagnosis
Fucosidosis can be prenatally diagnosed with tests such as chorionic villus sampling and amniocentesis which removes a sample of the fluid that envelops the fetus. The diagnosis of this condition can be determined during the first year of the infant’s life with the neurological deterioration, skeletal disease and intellectual disability. The clinical evaluation is possible with the tissue sample of the affected part of the body which when observed under the microscope reveals the abnormal cavities within the cells. The CT scan and the MRI imaging can confirm the deterioration of the white matter of the brain. In addition, urine analysis shows increased levels of fucose-containing complex compounds in the urine such as glycopeptiduria.
Treatment
There is no cure for this condition or to stop the progression of the symptoms. The treatment of fucosidosis is based on the various symptoms that are evident in each of the affected individuals. In addition, they may also require a routine check-up with various specialists such as neurology and ophthalmology. Antibiotic therapy can treat the recurrent respiratory infections. Genetic counseling may be beneficial for some of the affected individuals and their family.
References
https://rarediseases.org/rare-diseases/fucosidosis/
https://ghr.nlm.nih.gov/condition/fucosidosis#inheritance
http://www.ismrd.org/glycoprotein_diseases/fucosidosis/fact_sheet
