Diseases that affect a very small proportion of the population of a state, rare diseases are also known as orphan diseases. These diseases are rare but can be chronic, severe, and life-threatening. The field of rare diseases is complex and heterogeneous. The landscape of rare diseases is constantly changing, as new rare diseases and conditions are being identified and reported regularly in the medical literature.
Rare diseases are termed Orphan diseases because drug companies were not interested in adopting them to develop treatments. There are more than 7000 rare diseases. Only a few rare diseases are tracked when a person is diagnosed. These include certain infectious diseases, congenital disabilities, and cancers. It also consists of the diseases on state newborn screening tests. Because most rare diseases are not tracked, it is hard to determine the exact number of rare diseases or how many people are affected. There are different causes of different rare diseases; the majority are genetic, directly caused by changes in genes or chromosomes. In some cases, genetic changes that cause disease are passed from one generation to another. Many rare diseases, including infections, some rare cancers, and some autoimmune diseases, are not inherited.
Early diagnosis of rare diseases is a challenge owing to multiple factors that include lack of awareness among primary care physicians and lack of adequate screening and diagnostic facilities. Traditional genetic testing includes tests that can only address a few diseases. As a result, physicians most often provide their best guess on which tests are to be done. If the test is negative, further testing will be required using next-generation sequencing-based tests or chromosomal microarray, which are applicable but expensive and time-consuming processes with interpretation and counseling issues at times.
There is a lack of awareness about rare diseases in the general public and the medical fraternity. Many doctors lack appropriate training and awareness to correctly and timely diagnose and treat these conditions. Delay in diagnosis or a wrong diagnosis increases the suffering of the patients exponentially. There is an immediate need to create awareness amongst the general public, patients & their families, doctors, doctors’ training for early and accurate diagnosis, standardization of diagnostic modalities, and development of newer diagnostic and therapeutic tools.
A fundamental challenge in research and development for most rare diseases is that there is relatively little known about the pathophysiology or the natural history of these diseases. Rare diseases are challenging to research as the patient pool is very small, often resulting in inadequate clinical experience. Therefore, the clinical explanation of rare diseases may be skewed or partial. The challenge becomes even more significant as rare diseases are chronic, where long-term follow-up is essential.
Unavailability of treatment:
Availability and access to medicines are essential to reduce morbidity and mortality associated with rare diseases. In recent years, effective or safe treatment is not available for most rare diseases. Hence, even when a correct diagnosis is made, there may not be an available therapy to treat the rare disease. About 95% of rare diseases have no approved treatment, and less than 1 in 10 patients receive condition-specific treatment. Drugs are prohibitively expensive, placing immense strain on resources where drugs are available.
Cost of treatment:
As the number of persons suffering from rare individual diseases is small, they do not constitute a significant market for drug manufacturers to develop and bring drugs for them. They take medicines to treat rare diseases; the prices are incredibly high, apparently to recoup the cost of research and development.
Balancing competing priorities of public health in resource-constrained settings:
Rare diseases place a significant economic burden on any country, especially in resource-constrained settings. The financial capacity to support the exorbitant cost of treatment is an essential consideration in public health policy development regarding therapy for rare diseases. In resource-constrained stages, it is pertinent to balance competing public health interests to achieve the optimal outcome for the resources allocated. As resources are limited and have multiple uses, the policymakers have to prioritize a specific set of interventions over others. The appropriate choice is to support those interventions that would provide more healthy life years for a given sum of money while simultaneously looking at the equity. These interventions benefit the poor who cannot afford healthcare are prioritized.
Here are some ways to prevent and control rare diseases