Genetic Testing for Rare Diseases

3billion's buccal collection kit, 3billion portal page for physicians, and report

One test, 20,000 genes

Decoding the exome

The etiology and manifestation of rare genetic diseases are complex. The symptoms may be the same while the diseases are different, or the diseases may be the same while the symptoms are different.

With whole exome sequencing, >99% of the protein-coding regions of the human genome are analyzed, and the variants that show the highest association with the symptoms are interpreted, maximizing diagnostic yield.

Exome vs. Panel

  1. Coverage
    While panel testing only covers select genes that are known to be associated with certain diseases, whole exome testing covers all genes so that all potential variants are identified and interpreted.

  1. Continuous reanalysis
    New symptom, disease, and variant information can be incorporated into reanalysis for undiagnosed patients without the need for additional testing.

Test Features & Performance

Exome data generation

  • Sequencing platform Illumina NovaSeq 6000
  • Target enrichment IDT xGen Exome Research Panel V2
  • Read length 2x150 bp



  • Target regions the entire exome (~20,000 genes)
  • Mean depth ≥100x
  • Targeted regions covered at >20X ≥98%
Turnaround time: Within 6 weeks (30 business days)

*Our test is not clinically validated for copy number variants; thus, these findings should be validated by an alternate clinical test that is designed to identify such variants.

Improved diagnostic yield by advanced interpretation

  • Self-developed automated variant prioritization system, EVIDENCE
  • Variant classification according to the criteria of ACMG guidelines
  • Analysis that incorporates phenotypic information
  • Continuous reanalysis for undiagnosed patients
  • Interpretation and confirmation by team of clinical geneticists
  • Follow-up support for clinicians

Bar image visualizing advanced interpretation

Diagnosis by continuous reanalysis


Why patients remain undiagnosed

Rare disease patients receive diagnoses at a rate of 25~57.5% by WES (Wright CF et al., 2018 , Monies D et al., 2019 , Trujillano D et al., 2017 , Stark Z et al., 2016). More than half of rare disease patients are not diagnosed initially and face the financial burden from additional genetic tests.


Reflect the latest evidence

There are nearly 300 new gene-disease findings every year. Incorporating these new findings into our reanalysis improves the diagnostic rate of undiagnosed patients.


Incorporate new symptoms

Patients' symptoms may change over time or new symptoms may appear. This information is crucial for variant interpretation during reanalysis and can help end their diagnostic odyssey.

Testing you can trust

We have collaborated with more than 200 medical institutions across more than 45 countries* and have together diagnosed more than 10,000 rare disease patients. In our initial pilot study (N=330), ~43% of patients received diagnoses based on our data after clinical reassessment and family segregation testing (Seo GH et al., 2020).
*as of Jan 2022

CAP: College of American Pathologists
Our laboratory has received
CAP accreditation.
View Certificate

A closer look at our report

Report of 3billion's rare disease genetic test

Variant interpretation

We provide a list of identified variants that may be related to the patient's phenotype. For each variant, detailed information such as its classification and associated diseases are provided.

Secondary findings (optional)

Information on any identified variants of ACMG’s list of 73 genes are provided.

Test specifications

Test information, such as sequencing coverage, depth, and limitations, is provided.

See for yourself:

How 3billion's test works

5 diagnosis process: Order, Sample transportation, Genome sequencing, Interpretation, and Result

Test orders must be placed online by a physician.
Need help?


Prepare and send the patient's sample (buccal swab, blood, or extracted DNA) with the printed requisition form and informed consent form. We provide buccal swab collection kits upon request. If you would prefer to use your own kits, please refer to our
sample preparation guidelines.


Once we receive the sample and documents at our lab, the sample is accessioned and DNA is extracted.


The DNA is checked with rigorous quality control standards and sequenced, after which variants are prioritized by EVIDENCE.


Our team of medical genetics doctor and geneticists confirm and interpret the variants with the patient's symptoms. The results report is delivered to the physician.