One in 50 people is a carrier. Two carriers have a one-in-four chance with every pregnancy. And today, knowing before symptoms appear means access to therapies that can change the entire trajectory.
Whole genome sequencing identifies SMN1 deletions and SMN2 copy number — enabling presymptomatic treatment with gene therapy or disease-modifying medication.
Spinal Muscular Atrophy (SMA)
Spinal muscular atrophy (SMA) is an autosomal recessive motor neuron disease caused by loss of function of SMN1 (survival motor neuron 1) gene, resulting in degeneration of anterior horn motor neurons. Incidence is approximately 1 in 6,000–10,000 live births; carrier frequency is approximately 1 in 50 across populations. SMA is characterized by progressive weakness, starting proximally and advancing distally, with respiratory and bulbar involvement in severe forms. The disease is classified into types based on age of onset and maximum motor function achieved: Type I (severe, onset <6 months, never able to sit independently, often fatal by age 2 without treatment), Type II (intermediate, onset 6–18 months, able to sit but never walk), Type III (mild, onset >18 months, able to walk), and Type IV (adult-onset). Approximately 95–98% of SMA cases are caused by homozygous deletion of SMN1 exons 7–8; the remaining cases result from homozygous or compound heterozygous point mutations. Disease severity is dramatically modulated by SMN2 copy number: SMN2 encodes an almost identical protein but with a critical splicing difference that produces mostly non-functional truncated protein; however, approximately 15% of SMN2 transcripts include exon 7, producing functional SMN protein.
SMN1 and SMN2 are nearly identical genes (99.9% sequence homology) located in tandem in chromosome 5q13—a region of high sequence homology and frequent copy number variation. SMN encodes survival motor neuron protein, crucial for snRNP biogenesis and mRNA splicing in neurons; loss of SMN protein causes motor neuron degeneration. SMN2 is present in multiple copies in most individuals (1–4 copies, median 2) due to duplication. While SMN2 cannot fully compensate for SMN1 loss due to exon 7 splicing deficiency, the number of SMN2 copies critically determines disease severity: 1–2 copies typically produce Type I (severe); 3 copies produce Type II (intermediate); 3–4 copies correlate with Type III (mild). Presymptomatic SMA patients discovered through newborn screening with 2–3 SMN2 copies are at risk for Type I or II; those with ≥4 copies have lower immediate risk, though early treatment can prevent phenotype expression regardless.
SMN1/SMN2 genotyping is critical for SMA diagnosis and therapy selection. Three approved therapies are available: nusinersen (Spinraza), an antisense oligonucleotide administered intrathecally that modulates SMN2 splicing to increase exon 7 inclusion and full-length SMN2 protein production; onasemnogene abeparvovec (Zolgensma), a gene therapy using AAV9 to deliver functional SMN1 cDNA intravenously as a single infusion—a one-time curative approach now preferred in presymptomatic patients; and risdiplam (Evrysdi), an oral splicing modifier enabling home-based treatment. Presymptomatic treatment (newborn-diagnosed infants) produces dramatically improved outcomes—most treated presymptomatic infants never develop observable SMA symptoms and achieve normal or near-normal motor milestones. SMN2 copy number helps predict natural disease severity and guides prognostication, though early treatment can prevent phenotype expression even in patients destined to be Type I.
Standard sequencing cannot reliably distinguish SMN1 from SMN2 due to high sequence homology. Specialized copy number analysis is required.
SMN1/SMN2 copy number determination requires specialized analysis
SMA is now on the RUSP (recommended uniform newborn screening panel) in most US states, and carrier screening is increasingly common. Standard sequencing cannot reliably distinguish between SMN1 and SMN2 copies due to their 99.9% sequence homology; specialized copy number analysis techniques (comparative genomic hybridization, MLPA, or targeted NGS with specialized read-mapping) are required. Carrier screening panels typically detect SMN1 deletion but may not accurately determine SMN2 copy number. Whole genome sequencing with specialized copy number detection algorithms can provide accurate SMN1/SMN2 copy number assessment, enabling comprehensive carrier screening and disease severity prediction.
SMN2 copy number determines severity and guides presymptomatic therapy
SMN2 copy number is the primary severity modifier: 1–2 copies predict Type I disease (severe, infantile-onset); 3 copies predict Type II (intermediate, onset 6–18 months); 3–4 copies correlate with Type III (mild, ability to walk). Presymptomatic SMA patients discovered through newborn screening with 2–3 SMN2 copies are at risk for rapid disease progression and require immediate therapy initiation. Those with ≥4 copies have lower immediate risk but benefit from early treatment. Three approved therapies offer transformative outcomes: gene therapy (Zolgensma) is a one-time cure; antisense therapy (Spinraza) requires repeated intrathecal infusions; oral therapy (Evrysdi) enables home-based treatment. Documented in the medical record, SMN genotype enables presymptomatic diagnosis and rapid therapy initiation—preventing disease development and enabling normal motor development.
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.
Comprehensive insights and specialized reports
Easy to read and with answers you and your doctor can act on. Not a file to interpret — 200+ clinical reports, organized by category.
Your test becomes more valuable every year
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.
The results doctors bring to their hardest cases.
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.
Accredited by & published in
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 Spinal Muscular Atrophy (SMA) 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.
- Custom genomic reports for your members
- Group discounts and tailored packages
- Any country — including virtual groups
- Rare and common conditions covered
Message received.
We’ll be in touch within 2 business days. To follow up directly: hello@dantelabs.com
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
