Sanfilippo's disease is a rare and hereditary pathology. Also called type III mucopolysaccharidosis, It affects one in 70,000 births and causes serious neurological damage. There are four types of Sanfilippo's disease: A, B, C and D which correspond to four enzyme deficits.
This degenerative disease is caused by the accumulation of molecules called heparan sulfate in the body. These elements are normally eliminated or recycled by the body, but when they are not degraded, they concentrate in the cells and cause the pathology of Sanfilippo.
Sanfilippo's disease: what are the symptoms of this pathology?
Babies are not sick at birth. When they grow up, the first symptoms appear, because heparan sulphate continues to accumulate in the cells. The first manifestations of the disease occur around the age of three. Neurological damage is declared by:
These symptoms increase in intensity with age. Around the age of 10, generally, new manifestations appear as a deficiency of intellectual capacities, a reduction in motor capacities and a slight dysmorphia.
The airways of the lungs and nose can be regularly congested and these symptoms can be accompanied by lung infections. Because of these obstructions, patients may experience restless sleep, snoring, and sleep apnea. To clear the airways and reduce breathing pauses overnight, surgery can be done to remove the swollen glands in the throat.
Quite late, patients can develop joint and bone damage. They often start with the elbows before touching the arms, legs or even the knees. As they get older, patients begin to have difficulty performing movements.
Because of Sanfilippo's disease, delayed tooth growth is also possible. When they come out, the enamel is weakened with a grayish color. This pathology sometimes leads to macroglossia which is characterized by a widening of the tongue. This makes it difficult for patients to eat and swallow. Over the years, they have also suffered from repetitive ear infections that can cause hearing loss.
How is the diagnosis of Sanfilippo's disease made?
It is often announced late, as protests develop with age. Two methods are used to identify Sanfilippo's disease:
- the presence of a large amount of heparan sulfate in the urine of the child.
- the absence of one of the four enzymes responsible for Sanfilippo's disease (A, B, C, D)
When a child is affected by Sanfilippo disease, their parents can request a prenatal diagnosis for future pregnancies. It makes it possible to determine if the fetus is affected or not by the disease. The medical team can suggest two approaches to parents: either an amniocentesis, an amniotic fluid sample, or a chorionic villus biopsy to identify a genetic abnormality.
Sanfilippo disease: what are the treatments?
There is currently no treatment that can cure or alleviate the symptoms of Sanfilippo’s disease. Managing these events is also complicated, but research is progressing. In 2013, the Institut Pasteur started a gene therapy trial for type B Sanfilippo syndrome. For the purposes of the study, they recruited four children aged one and a half to four years. They were followed for 48 months by scientists.
Results: the treatment was well tolerated by the children. "It is associated with a change in the natural course of the disease in some of the children treated. Improvement in neurocognitive performance seems correlated from an early age " explains the Institut Pasteur on its platform. The results of the therapeutic trial were published in 2017 in the journal Lancet Neurology.
Sources: Institut Pasteur, Orphanet
Read also :
⋙ Neurology: what are the neurological diseases?
⋙ Angelman syndrome: what is this genetic neurological disease?
Hunt Huntington's disease: what is this rare neurodegenerative pathology?