10 facts about genetic testing for rare disease

By
Caty Reid
Dec 13, 2024
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  1. There are an estimated 300-400 million people worldwide living with a rare disease, while individually rare, these diseases collectively impact 3-5% of the population​.1

  1. 72% of rare diseases are genetic in origin, meaning there is a disease-causing variant in the individual’s DNA.1 

  1. As of today, on average, patients living with a rare disease wait 5-7 years for an accurate diagnosis, see up to 8 physicians, and experience 2 to 3 misdiagnoses.2 

  1. Over 6000 rare diseases are characterized by a broad diversity of disorders and symptoms that vary not only from disease to disease but also from patient to patient suffering from the same disease.1

  1. Genetic testing is necessary to determine if symptoms are caused by a genetic variant and to determine genetic risks for relatives

  1. Clinical genetic tests are different from direct-to-consumer (DTC) genetic tests. DTC tests cannot determine for certain whether or not you will get a disease or have a disease.

  1. Clinical genetic tests must be ordered by a provider.

  1. Clinical genetic tests include:
    1. Single Gene Testing
    2. Genetic Panels
    3. Whole-Genome (WGS) and Whole-Exome Sequencing (WES)3 

To learn more about each of these tests, visit our Genetic testing for rare disease article.

  1. Clinical genetic tests can be performed at home, using a saliva or buccal (cheek) swab, or at a lab using the same sample types or, where required, blood.

  1. Patients can apply for free, clinical genetic tests through Probably Genetic without going through their provider. A telehealth provider, employed by Probably Genetic, will sign-off on all appropriate orders.  

 

To learn more about how Probably Genetic is helping individuals through patient-first, free genetic testing programs please check out our full summary here.

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Over 100,000 patients have created a profile with Probably Genetic to confirm their eligibility for our free genetic testing and counseling programs.

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Category:
Rare Disease
Testing
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References
  1. Rare Disease Day 2025. Rare Disease Day 2025. Rare Disease Day 2025. Published October 3, 2024. https://www.rarediseaseday.org/ 
  2. Bick D, Jones M, Taylor SL, Taft RJ, Belmont J. Case for genome sequencing in infants and children with rare, undiagnosed or genetic diseases. J Med Genet. 2019;56(12):783-791. doi:10.1136/jmedgenet-2019-106111.
  3. A guide for the diagnosis of rare and undiagnosed disease: beyond the exome . Genome Medicine. 2022 Feb 28; 14(23). Marwaha S, Knowles JW, Ashley EA.
  4. Phillips et al. Orphanet Journal of Rare Diseases (2024) 19:297 https://doi.org/10.1186/s13023-024-03319-2