How genetic research helps diagnose rare diseases

Strengthening family dialogue contributes to early diagnosis and treatment of asymptomatic family members

It is not easy to be diagnosed with a rare, genetic and hereditary disease, and it is common for patients with various rare diseases to feel hesitant to seek out family members to talk about it. The reasons that can result in barriers to an honest conversation are different: people may be afraid of ruining relationships, being seen as guilty, or having a sense that it is private information.

However, proper early diagnosis and continued appropriate treatment avoid the factors that accelerate the progression of the rare condition. Patients with rare diseases pass through several doctors and specialties, and it takes on average up to seven or two years to receive the exact diagnosis of the pathology they are facing, which often exacerbates cases that could be avoided with proper treatment. Since more than 80% of rare diseases are genetic, it is important that people who receive the diagnosis encourage their family members – also asymptomatic – to check if they have also been affected.

About 13 million Brazilians are affected by rare diseases, according to a study by Interfarma, and 50% to 70% of the people affected by these diseases are children. Currently, there are 5,000 to 7,000 types of these diseases, and these numbers continue to increase regularly as new rare diseases are often described in the medical literature.

To be considered rare, diseases are analyzed according to their frequency in the population. The Ministry of Health accepts as a rare disease any condition with a frequency equal to or less than 65/100 thousand, ie 1.3 affected people per. 2,000.

Tracing the disease in the family is an important attitude because even in diseases with recessive genetic inheritance, parents, uncles and grandparents generally go about their lives normally and without imagining that they have a tendency to have children with rare diseases to this day. . they are born with a rare disease in the family. When relatives also have the opportunity to be tested for the disease, it opens up the possibility of diagnosing and treating asymptomatic family members before serious conditions develop.

Experience some rare diseases:

Multiple sclerosis

It is a neurological, chronic, progressive and autoimmune disease. Commonly diagnosed in patients between the ages of 20 and 40, it affects the brain, eyes and spinal cord – and does not cause dementia. In multiple sclerosis, the immune system defects healthy cells in the protective sheath of the nerve as “invading cells” and begins to attack them, eroding and damaging the myelin sheath.[v].

Pompe disease

It is a degenerative, progressive and inherited genetic neuromuscular disease that affects patients of all ages. An enzyme deficiency generates the gradual accumulation of glycogen in muscle cells, and as a result, the individual has muscle weakness, difficulty breathing and other symptoms that are confused with other common diseases.

Gaucher’s disease

People with Gaucher disease can see their symptoms occur at any time during their lives. Most cases, however, occur until adolescence. Diagnosis can take up to 10 years and approximately 25% of patients do not have access to adequate treatment due to late diagnosis.

Factory disease

Fabry’s disease, a rare, progressive and multisystem inherited genetic disease. Symptoms of Fabry’s disease include diarrhea, nausea, vomiting, abdominal pain, small red spots on the skin, intolerance to cold and / or heat, decreased sweating, proteinuria and others. As the disease progresses, the risk of developing fatal complications such as end-stage renal disease, stroke, cardiac fibrosis, arrhythmia and even death increases.


Symptoms and signs such as short stature, joint contractures, corneal opacity, enlarged tongue, spleen and liver usually occur in early childhood. Due to the many different symptoms, it is difficult to diagnose MPS, and many patients undergo more than 10 medical consultations before being referred to the right specialist.


It is a rare blood disease that causes blood clots in small blood vessels throughout the body. These small blood clots can block the flow to larger organs, such as the kidneys, brain or heart.


Acid Sphingomyelinase Deficiency (ASMD) is a rare and potentially fatal genetic condition, historically known as Niemann-Pick Disease type A, B or A / B. It is estimated that 1 in 200,000 people worldwide is born with the disease-causing gene. Due to this rarity and lack of knowledge on the subject, ASMD may not be detectable in the early stages, which implies progression of the disease and ultimately the death of the patient, even before a diagnosis is established – mainly in type A, considered the most serious.

Source: Compass – Exam

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