When taken cumulatively, rare diseases still affect a substantial proportion of the population. In the USA and the UK, some 1 in 15 to 1 to 20 people suffer from a rare disease, although definitions of what constitutes a rare disease differ. For instance, in the US, the Rare Diseases Act of 2002 defines a rare disease as affecting fewer than 200,000 people, whereas in the EU, the European Commission has a different benchmark, defining diseases as rare when they affect more than 1 in 2,000 people. So, what causes rare diseases, and how are they treated? Rare diseases have numerous genetic, environmental, idiopathic and unknown causes. In some cases, they originally stem from genetic mutations, which are later activated by environmental triggers. Here's a deeper exploration of how rare diseases are caused or triggered:

Factores genéticos
Os factores genéticos são a principal causa de muitas doenças raras. Estas doenças são frequentemente hereditárias e surgem quando genes específicos sofrem mutações, perturbando as funções corporais ou causando problemas de desenvolvimento.

Por vezes, os factores de risco genéticos a longo prazo são "activados" por estímulos a curto prazo.

• Cystic Fibrosis: Related to mutations in the CFTR gene, this disease primarily affects the respiratory and digestive systems by producing thickened mucus. It's passed on through a recessive inheritance pattern.
• Huntington's Disease: A neurodegenerative condition, Huntingdon’s is attributed to mutations in the HTT gene. Children have a 50% chance of inheriting the disease if one parent has the mutated gene.
• Children have a 50% chance of inheriting the disease if one parent has the mutated gene.
• Phenylketonuria (PKU): Affecting fewer than1 in 10,000 babies, PKU derives from mutations in the PAH gene, leading to an impaired ability to break down amino acids.

Factores ambientais

Embora a genética desempenhe frequentemente um papel no desenvolvimento das doenças raras, os factores ambientais podem exacerbar ou iniciar o seu aparecimento. Os factores ambientais desempenham um papel crucial, mas misterioso, no desenvolvimento de numerosas doenças, tanto comuns como raras.

Eis alguns casos conhecidos:

• Porphyria: Although having a genetic foundation, this disease group also reacts strongly to environmental triggers. Exposure to drugs, stress, sun, or certain foods can lead to an acute attack.
• Lupus: Affecting between 2 and 8 people per 100,000, Lupus has an underlying genetic risk, but external factors can instigate or worsen the disease. Sunlight, infections, and specific medications are known triggers.
• Paraneoplastic Pemphigus: While associated with cancers, trauma or specific

Causas desconhecidas
Nalguns casos, as doenças raras não têm uma causa principal consensual. Têm frequentemente origens multifactoriais que variam de doente para doente.

As doenças raras com causas mal compreendidas ou desconhecidas incluem:

• Reflex Sympathetic Dystrophy (RSD): A rare disease that causes chronic burning pain, the exact origins of RSD remain unknown. Injuries or surgical procedures can sometimes lead to its onset.

• Stiff Person Syndrome: Predominantly marked by muscle rigidity and spasms, this exceptionally rare disease – considered one of the rarest worldwide – is likely immune-system related.
• Chronic Fatigue Syndrome (CFS): CFS, though still considered rare, has become more common in recent times. It’s often associated with infection, but a conclusive cause has not been identified.

As estimativas actuais sugerem que existem entre 6000 e 8000 doenças raras conhecidas pela ciência.

Apenas 5% destas doenças têm tratamentos reconhecidos. Se uma doença rara tiver um único tratamento conhecido, este é designado por "tratamento órfão". Uma maioria significativa das pessoas que sofrem de doenças raras, juntamente com os seus prestadores de cuidados de saúde, são confrontadas com doenças que atualmente não têm vias terapêuticas concretas. Mais uma vez, embora a taxa de incidência de cada doença rara seja baixa, o impacto cumulativo é elevado, afectando cerca de 1 em cada 15 pessoas, em média.

O desenvolvimento de tratamentos para estas doenças apresenta um conjunto distinto de desafios. Dado o pequeno número de indivíduos diagnosticados com uma doença rara específica, a realização de ensaios clínicos exaustivos é problemática. Além disso, a angariação de fundos para a investigação das doenças raras também é complicada. De um modo geral, o financiamento da investigação das doenças raras tem aumentado, com 2023 a anunciar um investimento significativo de 14 milhões de libras do Medical Research Council (MRC) e do National Institute for Health and Care Research (NIHR) no Reino Unido.

  Embora as pessoas com doenças raras enfrentem muitas vezes percursos difíceis, há esperança.

The increased focus on research, development, and accessibility of treatments is paving the way for a brighter future. More doctors and clinicians are dedicating their research to rare diseases, increasing the availability of effective and novel treatments. Masters are a global pharmaceutical company that recognises the challenges associated with rare diseases and is committed to increasing accessibility to their medications. We are expert pharmaceutical drug suppliers making medicines available in emerging markets extends to rare diseases. We continually strive to transform lives through the power of medication