By Elllie Richards, PhD student

All living things, from people and animals to trees and bacteria, have a genome: a complete manual written in the language of DNA. This encodes instructions for how to make proteins, the building blocks that make and control our bodies, controlling everything from cellular motility and survival all the way up to eye colour. Whilst everyone within our species has the same book, we can have different editions, phrasing, sentence order and typos that can change in each book. This genetic variation is incredibly important for the survival of a species as mutations in our immune system, altered metabolic processes and energy storage, could be an advantage that prevents a virus or environmental changes from wiping us out.

But sometimes, these alterations to our genetic manuals can be detrimental. Imagine trying to read a story where letters are missing, sentences are chopped, or whole paragraphs vanish. This is how genetic diseases arise: when the body’s instructions become jumbled or incomplete. Some genetic conditions show up at birth, especially if they disrupt early development, while others emerge later in life. Rare genetic diseases are classified as a disorder affecting less than 1 in 2,000 of the general population. There are between 5,000 and 8,000 known rare diseases¹, which are often lifelong and/or life limiting.

The most common way of identifying the genetic causes behind these diseases is through genetic testing on individual patients and large population studies (GWAS). This enables researchers to identify tiny changes in DNA, sometimes affecting just a single letter (SNVs), as well as larger structural changes in chromosomes. These studies can also show how certain genetic changes are often inherited together in a pattern known as linkage disequilibrium (LD). This helps uncover the biological roots of diseases, points towards new treatments, and allows doctors to make more accurate diagnoses by looking at a patient’s genome.

However, the effectiveness of these approaches depends on who is included in the research. Despite individuals of European descent comprising approximately 16% of the population, they represent almost 80% of all GWAS participants². Things like SNV frequency, and LD that influence GWAS findings vary significantly across populations, with some SNVs being completely unique to a specific ethnicity³. This means that genetic variants that are common in underrepresented populations might be wrongly labelled, causing people to wait longer for answers or receive the wrong diagnosis. It also holds back promising new treatments, like gene-targeted therapies that rely on precise genetic information ⁴.

So why do non-European communities often find themselves left out of rare disease research, even though their views and experiences are equally valid? Communication is essential in the medical field, whether it’s understanding the symptoms a patient is describing, explaining treatment options, or recruiting participants for a study. Research shows that clinicians felt less comfortable approaching non-English speakers for trials or studies, as they believed them to be uninterested in taking part ⁵. This institutionalised bias arises from the fact that most information and consent forms are written only in English, making it harder for non-English speakers to access or trust medical research. Medical jargon adds another barrier, since the terms used by medical professionals do not have direct translations into other languages. This further alienates patients and their families, leaving them feeling disrespected, less likely to trust doctors and less likely to take part in clinical trials and studies⁶.

It is also very difficult to create change in these spaces, as public and company awareness and interest in rare diseases remain low. Because each condition affects a relatively small number of individuals compared to something like diabetes, research into, and treatments for, these conditions are financially unattractive to pharmaceutical companies, meaning less than 5% of rare diseases have a licenced treatment ⁷. Additionally, individuals in low-income and rural areas may have few or no rare disease experts nearby. A lack of awareness and testing methods among local care providers leads to delays in diagnosis and access to treatment, as well as a lack of inclusion in clinical studies ⁸.  This contributes to the statistic of 1 in 4 rare disease patients being misdiagnosed at least once. Not only does this cause disease progression and worse outcomes for the patient, but it also significantly increases direct medical costs with a €249 billion burden in Europe alone  ⁹.

Therefore, ensuring equity, not just equality, in rare disease research is essential. Equality means treating everyone the same, but equity recognises that people start from different places and need different resources to achieve the same outcomes. Large-scale studies must be redesigned so historically underrepresented communities have the same access to diagnosis, treatment, and research benefits. Funders should support schemes that promote research into rare disease, including translating consent forms and patient information materials into different languages and using more accessible terminology. Building research partnerships with marginalised populations, culturally competent communication, and expanding genetic testing and specialist care in underserved areas are equally important. Market failures that leave many rare conditions without treatments must be addressed through public–private partnerships and repurposing existing drugs. Most importantly, patients must be treated as partners in research, helping design studies and set priorities. These steps will raise awareness, improve diagnosis, and build trust in science. Achieving equity requires deliberate, structural change so no one is left behind.

1. Genomics England (2026). Rare disease genomics. https://www.genomicsengland.co.uk/genomic-medicine/understanding-genomics/rare-disease-genomics.
2. Genetics for all. (2019). Nature Genetics 51, 579-579. 10.1038/s41588-019-0394-y.
3. Han, H., Seo, G.H., Hyun, S.I., Kwon, K., Ryu, S.W., Khang, R., Lee, E., Kim, J., Song, Y., Jeong, W.C., et al. (2025). Exome sequencing of 18,994 ethnically diverse patients with suspected rare Mendelian disorders. NPJ Genom Med 10, 6. 10.1038/s41525-024-00455-3.
4. Sirugo, G., Williams, S.M., and Tishkoff, S.A. (2019). The Missing Diversity in Human Genetic Studies. Cell 177, 26-31. 10.1016/j.cell.2019.02.048.
5. Hussain-Gambles, M., Atkin, K., and Leese, B. (2004). Why ethnic minority groups are under-represented in clinical trials: a review of the literature. Health Soc Care Community 12, 382-388. 10.1111/j.1365-2524.2004.00507.x.
6. Pardhan, S., Sehmbi, T., Wijewickrama, R., Onumajuru, H., and Piyasena, M.P. (2025). Barriers and facilitators for engaging underrepresented ethnic minority populations in healthcare research: an umbrella review. Int J Equity Health 24, 70. 10.1186/s12939-025-02431-4.
7. eClinicalMedicine (2023). Raising the voice for rare diseases: under the spotlight for equity. EClinicalMedicine 57, 101941. 10.1016/j.eclinm.2023.101941.
8. Cohen, A.S.A., Berrios, C.D., Zion, T.N., Barrett, C.M., Moore, R., Boillat, E., Belden, B., Farrow, E.G., Thiffault, I., Zuccarelli, B.D., and Pastinen, T. (2024). Genomic Answers for Kids: Toward more equitable access to genomic testing for rare diseases in rural populations. Am J Hum Genet 111, 825-832. 10.1016/j.ajhg.2024.03.016.
9. Tim, W., Kirsten, A., Rajini, J., Charlotte, P., Ashutosh, M., Angelina, P., and Luca, C. (2024). The Economic Cost of Living with a Rare Disease Across Europe.

Barriers to breakthroughs – why ensuring equity in rare and genetic disease research should matter to us all / Institute of Genetics and Cancer by blogadmin is licensed under a Creative Commons Attribution CC BY 3.0

Share