Aurora magazine

Chronic intestinal atrial dysrhythmia syndrome (CAID) is a rare disease discovered only in 2014 and also called "Viking syndrome". It is caused by a rare genetic mutation and affects both the heart and the intestine. The contractions of the two organs are in fact linked to a single gene, which would be the one affected by the disease.

A team of Canadian researchers has developed a diagnostic test for the disease, based primarily on clinical analyzes. In fact, those who suffer suffer heart and intestinal problems, both of a rather serious entity. Heart problems include slow heartbeat, which forces 50% of patients to implant a pacemaker. Instead, digestive problems manifest themselves with chronic intestinal obstructions, which can only be dealt with by intravenous feeding.

For the time being, no less invasive treatments are available. The disease is indeed rather young. Scientists discovered it by analyzing the DNA of some Canadian patients of French and Scandinavian origins. All patients showed both cardiac and gastrointestinal symptoms, related to a mutation of the SGOL1 gene. Studies in guinea pigs with similar symptoms have confirmed the role of the gene in the development of the disease.

According to the researchers, the mutation of SGOL1 is likely to reduce the protection of certain cells in the intestine and heart. When in health, the gene could in fact have the task of maintaining the rhythm of the heart throughout its life. When the mutation is present, the cells begin to multiply uncontrollably and grow older.

Source: umontreal.ca

Fatal familial insomnia is a genetic neurodegenerative disease described for the first time in 1986. As the name implies, it is always fatal and has a course that fluctuates between a few months and 2 years. Usually the first symptoms appear between 37 and 61 years, although there are cases even under 30 years. A more precise estimate is complicated, since today there are only 57 cases confirmed in 27 families in the world.

It is a prion disease, caused by proteins with an irreversibly altered structure, prions. These are found mainly in the plasma membrane of the brain and their function is unclear. The anomaly of fatal familial insomnia causes an accumulation of prions in the brain tissue. As the accumulation increases, the diseased cells also infect the others and kill the neurons.

The first symptom is insomnia, not even negotiable with barbiturates. Prions accumulate in the thalamus, the area of ​​the brain that regulates the sleep-wake cycle, and prevent sleep. The symptoms are not treatable and worsen within a few months, also causing hallucinations and delirium. Neurological damage causes abnormal movements and involuntary jerking, as well as dementia and a progressive inability to walk. Toward the end of the course, the patient is completely unable to sleep.

The anomaly is caused by a mutation of the PRNP gene and is autosomal dominant. So just a single copy of the gene is enough for the disease to manifest. Genetic tests are used to confirm the diagnosis, usually done by clinical analysis and FDG-PET scan. If the diagnosis is confirmed, prenatal testing is also available for those at risk.

Source: osservatoriomalattierare.it

Choroideremia is a genetic disease that affects about 1 newborn every 50,000-100,000, especially males. The disease manifests itself in the first 10 years of life with a progressive narrowing of the peripheral visual field. Before the age of 40, complete vision loss and subsequent blindness occur.

In the choroideremia the progressive degeneration occurs of:

retinal
choroid
retinal pigment epithelium
photoreceptor

The latter are the cells placed at the back of the eye, which collect light.

The first symptom of choroideremia is the lowering of vision in low light conditions. The lack of photoreceptors makes it difficult to collect the little light available in the environment. Then the visual field begins to shrink and leads to the so-called tubular vision. In adult age this translates into total loss of sight. It usually happens around the age of 40, but the timing may change depending on the patient's condition.

Progressive loss of vision remembers what happens in other types of retinal degeneration, such as X-linked retinitis pigmentosa or turned atrophy. This complicates the diagnosis, especially if there are no cases known in the family. The assessment of the fundus of the eye and the dosage of ornithine levels can help to obtain a more precise diagnosis, but not always enough. Genetic tests can be used to confirm the diagnosis.

The disease is caused by the mutated version of the CHM gene, which encodes the REP-1 protein. About 20% of patients do not show the mutation, so it is likely that there are other genes involved.

For the moment there are no definitive therapies. The only possible treatment is to make the most of the visual function, also thanks to technical support for low vision. These have helped and help many patients to lead an almost normal life, although unfortunately there is still no way to stop the progression of the disease.

Source: retinaitalia.org

X-linked myotubular myopathy is a rare genetic disease that affects 1 child per 50,000. It is a neuromuscular disease that only affects males and manifests itself from birth. The newborn is weak and struggles to breathe. In some cases, there are even prenatal symptoms, such as the almost absence of fetal movements.

After an initial clinical observation, the child's chest radiograph is taken. This reveals the thinning of the ribs. Other indications are the excessive body length, the skull too large, the paralysis of the muscles of the eyeballs. Some patients experience vascular lesions at the level of the liver and a thickening of the pyloric channel, but only in those who live longer.

Most of the healthy women carriers are asymptomatic, except for some small clues. Healthy carriers tend to be weak and may experience urinary incontinence. This is due to a smooth muscle involvement.

Myotubular myopathy is caused by mutations in the myotubularin gene. Diagnosis is based on clinical analyzes, muscle biopsies and genetic tests. If there are cases among the known relatives, the doctors recommend genetic counseling to the whole family.

Unfortunately, to date there is no decisive cure or effective treatment. Doctors attempt a multidisciplinary approach, at least to stem the symptoms of the disease. Even in this way, the course proves to be fatal in the first months of life. However, it happens that some subjects manage to reach adolescence, thanks to medical interventions and ventilation.

Source: orpha. net