Familial Adenomatous Polyposis — hundreds to thousands of colorectal polyps driven by APC loss-of-function, with near-certain cancer transformation without surgical intervention.
Whole genome sequencing reads the complete APC gene sequence — including deep intronic regions, large deletions, and mosaic variants that standard hereditary cancer panels systematically fail to detect.
Familial Adenomatous Polyposis
Familial adenomatous polyposis (FAP) is an autosomal dominant hereditary colorectal cancer syndrome caused by pathogenic variants in the APC (adenomatous polyposis coli) tumor suppressor gene on chromosome 5q22.2. Classic FAP is characterized by the development of hundreds to thousands of adenomatous polyps throughout the colorectum, typically appearing in the second decade of life. Without surgical intervention, colorectal cancer is virtually inevitable by the fifth decade — lifetime colorectal cancer risk approaches 100% in untreated classic FAP. FAP accounts for approximately 0.5-1% of all colorectal cancers and is estimated to affect 1 in 5,000 to 1 in 10,000 individuals.
Attenuated FAP (AFAP) is a milder phenotypic variant caused by variants in specific APC regions (the 5' end, exon 9, or the 3' end) and is characterized by fewer polyps (10-100), later onset of polyposis, lower but still substantially elevated colorectal cancer risk, and more variable expression. Genotype-phenotype correlations in FAP are well-established: variants in codons 1250-1464 (particularly codon 1309) are associated with dense polyposis and earlier colorectal cancer; variants at codons 1310-1330 and 1445-1580 are associated with a higher risk of desmoid tumors; and variants at the 5' end are associated with AFAP. Extracolonic manifestations — including duodenal adenomas (100% lifetime risk), thyroid cancer, hepatoblastoma (in children), desmoid tumors, congenital hypertrophy of the retinal pigment epithelium (CHRPE), and osteomas — vary by APC variant location.
Approximately 20-30% of classic FAP arises from de novo APC variants without a family history of polyposis. An additional 7-10% of patients who meet clinical criteria for FAP have no detectable APC variant by standard sequencing — this group may harbor deep intronic splicing variants, large genomic rearrangements (deletions, duplications), or somatic mosaicism that standard gene panel testing cannot detect. MUTYH-associated polyposis (MAP), caused by biallelic MUTYH variants, can produce a phenotype indistinguishable from attenuated FAP and requires concurrent MUTYH genotyping in APC-negative polyposis patients.
Classic FAP, attenuated FAP (AFAP), and MUTYH-associated polyposis (MAP) produce overlapping clinical pictures with distinct genetic causes and surgical implications. APC variant location determines extracolonic manifestation risk.
Standard hereditary cancer panels read APC coding exons. They miss deep intronic variants, large rearrangements, and mosaic mutations — the variants that explain negative panels in clinically affected families.
Up to 30% of clinically diagnosed FAP patients test APC-negative on standard panels
Standard hereditary cancer panels sequence the APC coding region and splice sites. They do not reliably detect large genomic deletions or duplications spanning multiple exons, deep intronic variants that create aberrant splice sites, or somatic mosaicism — where the APC variant is present in only a fraction of cells. Studies have found that 7-10% of classic FAP patients with no identified APC coding variant carry deep intronic or structural rearrangement variants detectable only by comprehensive genomic analysis. An additional subset harbor somatic mosaic APC mutations, where variant allele fractions of 10-20% may be missed by standard panel sequencing depths. Whole genome sequencing at 30X coverage with copy number variant analysis resolves all of these.
APC variant location determines surgical strategy and surveillance intensity
Colorectal surgical management in FAP is not one-size-fits-all. Patients with codons 1250-1464 variants and dense polyposis typically require restorative proctocolectomy with ileal pouch-anal anastomosis. Patients with AFAP or sparse polyposis may be managed with segmental colectomy with ileorectal anastomosis and endoscopic surveillance. Desmoid risk stratification — critical for surgical planning in patients with intra-abdominal desmoid tumor risk — depends on APC variant location at codons 1310-1580. None of these genotype-phenotype stratifications are possible without a complete APC genotype, which requires sequencing the full gene including regulatory and intronic regions.
Your full DNA (not just a part of it)
Traditional genetic testing looks at narrow sets of genes, missing most parts of your genome. We sequence your full genome — every gene and every region between genes.
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Easy to read and with answers you and your doctor can act on. Not a file to interpret — 200+ clinical reports, organized by category.
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Your DNA does not change, but genome science is accelerating. Every month, new variant-disease associations are discovered. We validate these findings and update your reports automatically. Your test becomes more valuable every year.
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Forty years of uncertainty. One test.
A patient had spent decades in the UK healthcare system without a diagnosis. Dante data, accepted by NHS clinical teams at Queen Elizabeth University Hospital Glasgow, identified Noonan Syndrome and a RUNX1 leukemia-associated variant that had gone undetected. After 40 years, they finally had an answer.
A complete read delivers a complete picture.
A patient came to Dante to investigate periodic paralysis. Reading the complete genome identified a concurrent hereditary cardiac finding — Brugada syndrome — that their doctor confirmed with an ECG. The result also explained a family member's unresolved cardiac history. One test. Every answer in it.
Sequenced in 2019. The data worked in 2021.
Jennifer sequenced her genome with Dante two years before her breast cancer diagnosis. When treatment began, Dante's pharmacogenomics data showed her prescribed chemotherapy would cause serious adverse effects. Her doctor selected an alternative — and she started effective treatment from day one.
Every genetic question deserves a complete answer.
Whether you are searching for answers today or protecting your health for tomorrow, a complete read of your entire genome is the only place to start.
It runs in your family. Now you can know if it runs in your genes.
Your genome contains inherited variants associated with medical conditions like cardiac, cancer, and neurological. We read all of them — with the clinical depth to give the result meaning.
Learn more →When traditional lab tests say you're fine. And you know you're not.
Standard diagnostic tests check for a pre-selected set of answers. We sequence your full DNA — including parts that no test was designed to check. If the answer is in your genome, we will help you find it.
Learn more →Your diagnosis may be right. Your treatment plan may be incomplete.
Your genes determine which treatments are most likely to work — and which are not. We give your doctor the tools and insights to inform your treatment plan.
Learn more →You want to know before something forces the question.
Some people don't wait for a diagnosis or a family history to act. Whole genome sequencing gives you the complete genetic picture now — so you and your doctor can make informed decisions before anything becomes urgent.
Learn more →You already took a DNA test. Here's what it couldn't tell you.
Most consumer DNA tests read less than 0.1% of your genome. We read all of it.
Learn more →Clinical-grade results. Chosen by individuals, trusted by doctors for their most complex cases.
Dante Genome Test helped specialists at a UK national acute hospital in the identification of Noonan Syndrome and a rare leukemia-associated genetic variant that had gone undetected. That result changed the medical care of the patient.
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Common questions about whole genome sequencing.
What is the difference between whole genome sequencing and a targeted genetic test?
Targeted genetic tests — including standard hereditary cancer panels — read a pre-defined list of known variants in a specific set of genes. They are designed to find what they already know to look for. Whole genome sequencing reads your entire genome: all 6 billion base pairs, every gene, every region between genes. A Mayo Clinic study published in JAMA Oncology found that standard testing guidelines missed more than half of patients with inherited cancer mutations. Genome Test does not have a fixed list.
What will I receive when my results are ready?
Your Dante Genome delivers 200+ physician-ready reports organized by clinical category — hereditary cancer, cardiac conditions, rare diseases, pharmacogenomics, carrier status, and more. Reports are delivered to your secure Genome Manager and are formatted for direct clinical use. Your genome data is permanently retained and re-analyzed automatically as science advances.
What happens if a clinically significant variant is found?
If a pathogenic or likely-pathogenic variant is identified, it will be clearly flagged in your physician-ready report with clinical context, published evidence, and recommended next steps. We recommend sharing any clinically significant finding with your physician or a genetic counselor, who can guide decisions about surveillance, risk reduction, or cascade testing for family members.
How is this different from a consumer DNA test like 23andMe or AncestryDNA?
Consumer DNA tests use genotyping chips that read less than 0.1% of your genome — a tiny pre-selected set of common variants. They are optimized for ancestry and population-level traits, not clinical genetic findings. The Dante Genome Test sequences 100% of your genome at 30X coverage, the same standard used in clinical diagnostic settings. The two tests are not comparable in scope, methodology, or clinical utility.
How long does it take to get results, and how are they delivered?
Your collection kit ships within 48 hours of ordering. Once your sample arrives at our CLIA-certified laboratory, sequencing and analysis takes 6–8 weeks. Results are delivered securely to your Genome Manager, where you can access your reports, share them with your physician, and receive automatic updates as new findings are validated against your genome.
We work with patient advocacy groups worldwide.
Dante Labs works with patient advocacy groups of any size — for Familial Adenomatous Polyposis and other conditions, rare and common. We support groups in any country, including virtual patient advocacy groups.
We can provide customized reports, group discounts, and packages tailored for your members. Please reach out using the form and we'll be in touch within two business days.
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One test.
A lifetime of answers.
One kit, sent to your home. Your entire genome sequenced at the clinical standard used for diagnostic decisions. 200+ physician-ready reports delivered to your Genome Manager in 6–8 weeks — permanent and updated as science advances.
Ships within 48 hours · Results in 6–8 weeks
