Leukodystrophy is a neurodegenerative disease resulting from an accumulation of sulfatides (glycolipid type) in the brain.
Definition of leukodystrophy
Leukodystrophy is a neurodegenerative pathology. It is the consequence of an abnormal accumulation in the nervous system of a substance that combines lipid and carbohydrate: a glycolipid. These glycolipids, source of leukodystrophy, are sulfatides. the disease is therefore the result of an accumulation of sulfatids in the nervous system, but also the kidneys.
Leukodystrophy is a rare disease, with an incidence of between 0.5 and 1 case in 50 000 individuals.
Three foci of leukodystrophy
- the late infantile form: for nearly 60% of cases of leukodystrophy
- the juvenile form: which concerns between 20% and 30% of cases of leukodystrophy
- the adult form: which concerns between 10% and 20% of cases of leukodystrophy
The late infantile form is therefore the most frequent. This first form appears from the first steps of the child. The latter then presents a hypotonia (weakening of the muscular tone), disorders in the way of walking, optic atrophy (inflammation of the optic nerve), or a regression of motor skills.
Causes of leukodystrophy
Leukodystrophy is a genetic inherited disease. It is transmitted autosomally recessive. That is, the mutated gene of interest is located on an autosome (non-sexual chromosome) and the presence of two copies of the gene in question is necessary in the development of the disease (one from the mother, and one from the mother). from the father).
The presence of the mutated gene causes an anomaly in the formation of the enzyme capable of degrading the sulfatids of the brain. Depending on the forms of the disease, this inability to remove these substances from the brain, is more or less important. In fact, in the infantile form, the enzymatic activity is almost nil. In the juvenile form, this deficiency of enzymatic activity is less important. Finally, in the context of an adult form, the enzymatic activity remains residual.
Who is affected by leukodystrophy?
As this is an inherited autosomal recessive disorder, patients with leukodystrophy have their father and mother also affected by the disease.
The recessive nature of leukodystrophy means that if the child has only one copy of the gene of interest, it will not display the characteristics of the disease. The presence of both copies of the mutated gene is necessary in the development of the pathology.
Evolution and possible complications of leukodystrophy
The accumulation of sulfatides in the brain leads to decerebration (destruction of the brain). This usually occurs 5 years after the first clinical signs.
As a result, the search for these substances in the urine or sulfatiduria is important and essential in the early and rapid management of the disease.
Symptoms of leukodystrophy
Leukodystrophy is a neurodegenerative disease. Clinical signs and associated symptoms are related to:
- motility disorders (walking for example)
- psychiatric manifestations (behavioral disorders, chronic anxiety , etc.)
- of seizures
- Optic atrophy
Risk factors for leukodystrophy
Since leukodystrophy is a hereditary recessive inherited disease, the only risk factor is therefore the presence of the mutated gene in the family context (presence in the father and the mother).
How to treat leukodystrophy?
Currently, no cure for the disease has yet been developed. A therapy based on the substitution of the deficient enzyme is under study.
In the context of a leukodystrophy of infantile or juvenile form, a bone marrow transplant makes it possible to stabilize the neurocognitive functions but this is not entirely guaranteed.