Genetic testing for rare disease

Decoding hope: how genetic testing transforms rare disease diagnosis

For the millions affected by rare diseases, the journey to a diagnosis can feel hopelessly long. For the estimated 300 million people worldwide living with a rare disease, the path to understanding unexplained symptoms is fraught with delays, misdiagnoses, and an unwavering uncertainty.¹

For many patients with a rare disease, genetic testing can transform the diagnostic journey; shortening time to diagnosis and providing answers to symptoms that may have been hidden in the patient’s DNA all along. 

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What are rare diseases?

Rare diseases are conditions affecting fewer than 1 in 2,000 people. While individually rare, these diseases collectively impact 3-5% of the population​.¹ Astonishingly, 72% are genetic in origin, often manifesting early in life and leading to chronic, progressive, or life-threatening complications​.¹

Challenges like overlapping symptoms and heterogenous presentation of symptoms across patients (meaning, two patients with the same condition may have entirely different symptoms from each other) often delay diagnoses. On average, patients wait 5-7 years, consult up to 8 specialists, and endure multiple misdiagnoses before receiving clarity.²

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How genetic testing works

Genetic testing analyzes DNA to identify changes, known as variants or mutations, that may lead to disease. Using a blood or saliva sample, tests are conducted to pinpoint specific genetic markers, helping to provide clarity on unexplained symptoms. Depending on the suspected condition, several types of genetic tests may be used:

1. Single Gene Testing: Focuses on specific genes linked to certain conditions, such as Duchenne muscular dystrophy or sickle cell disease​.³
2. Genetic Panels: Examines multiple genes simultaneously, making it ideal for conditions caused by variants in different genes, such as epilepsy or primary immunodeficiency​.³
3. Whole-Genome and Whole-Exome Sequencing: Comprehensive approaches that evaluate large portions of DNA to identify rare or complex genetic causes.³

These methods provide critical insights not just for diagnosis but also for guiding treatment plans.

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Why genetic testing matters

For individuals with rare diseases, the benefits of genetic testing extend far beyond diagnosis:

• Early Detection: Identifying genetic variants before symptoms arise can help initiate preventive measures or early interventions.
• Targeted Treatment Plans: By understanding the genetic cause of a condition, healthcare providers can develop personalized treatment strategies.
• Family Insights: Since DNA is shared among family members, a diagnosis can provide vital information about the genetic risks for relatives.³
• Emotional Relief: Many individuals find comfort in understanding the cause of their symptoms, which helps alleviate the stress of prolonged uncertainty.

“For three years, we were guessing, not knowing the cause of husband’s symptoms. The most his diagnosis was narrowed to was 'maybe FTD' or 'possibly early-onset Alzheimer’s'.” Linda, a caregiver for her husband Mark, shares. “We needed to put an end to the uncertainty. I applied for free testing with Probably Genetic and that genetic test gave us the answer—Mark carries the MAPT gene responsible for FTD. While there may not yet be a cure for FTD, knowing the cause has brought us immense relief and allowed us to move forward with clarity.”

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The role of genetic counseling

Genetic testing is a significant step that comes with questions and emotions. Genetic counseling ensures patients fully understand their test results and what they mean for their health and family. Counselors can also help individuals decide whether testing is the right choice based on personal and family medical histories.

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A path toward answers

For those facing unexplained symptoms or a history of rare diseases in their family, genetic testing offers a pathway to clarity and care. While the process may seem daunting, advancements in genetic research and testing technology have made it more accessible and effective than ever before. 

If you’re navigating symptoms that you do not yet have an accurate diagnosis for, consider speaking with your healthcare provider about genetic testing. If you are unable to obtain genetic testing through your healthcare provider, consider applying for Probably Genetic’s free genetic testing & counseling. 

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Genetic testing for rare disease facts 

See “10 Facts About Genetic Testing for Rare Disease” if you’d like to see some of the statistics from this article, as well as other statistics, in an easy to review format.

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