Glycogen Storage Disease Type I — where the specific gene (G6PC vs. SLC37A4) determines whether the patient faces only metabolic challenges or also develops neutropenia, recurrent infections, and inflammatory bowel disease requiring additional targeted therapy.
Whole genome sequencing distinguishes GSD type Ia (G6PC) from type Ib (SLC37A4) — a critical distinction because type Ib patients develop neutropenia treatable with empagliflozin, a repurposed SGLT2 inhibitor that has transformed type Ib management.
Glycogen Storage Disease Type I
Glycogen storage disease type I (GSD-I, von Gierke disease) is an autosomal recessive disorder of glucose metabolism caused by deficiency of either glucose-6-phosphatase-α (type Ia, G6PC gene, chromosome 17q21.31, ~80% of cases) or the glucose-6-phosphate translocase (type Ib, SLC37A4 gene, chromosome 11q23.3, ~20%). Both subtypes prevent the final step of hepatic glycogenolysis and gluconeogenesis — the dephosphorylation of glucose-6-phosphate to free glucose — causing severe fasting hypoglycemia, hepatomegaly, hyperlipidemia, hyperuricemia, and lactic acidosis. GSD-I affects approximately 1 in 100,000 births.
GSD-I presents in infancy with hepatomegaly (massive glycogen accumulation), severe fasting hypoglycemia (symptomatic within 3-4 hours of fasting), lactic acidosis, hyperlipidemia (triglycerides often >1,000 mg/dL), and hyperuricemia. Long-term complications include hepatic adenomas (developing in 50-75% of patients by adulthood, with malignant transformation risk), gout, nephrolithiasis, progressive renal disease, and osteoporosis. Dietary management — continuous glucose supply through frequent meals, uncooked cornstarch (which provides sustained glucose release), and nocturnal gastric drip feeding — prevents hypoglycemia and reduces metabolic derangements.
The critical phenotypic distinction between types Ia and Ib is that type Ib patients develop neutropenia and neutrophil dysfunction — causing recurrent bacterial infections, oral ulcers, and inflammatory bowel disease (IBD-like) — in addition to the metabolic phenotype shared with type Ia. Empagliflozin, an SGLT2 inhibitor repurposed from diabetes treatment, has dramatically improved neutropenia and IBD symptoms in GSD type Ib by reducing intracellular glucose-6-phosphate accumulation in neutrophils. This gene-specific therapy makes molecular genotyping essential: type Ia patients do not develop neutropenia and do not benefit from empagliflozin.
Empagliflozin — a diabetes drug repurposed for GSD type Ib — has transformed management of the neutropenia and IBD-like colitis that type Ib patients develop. This therapy is only indicated for type Ib (SLC37A4), not type Ia (G6PC).
Type Ia vs. type Ib distinction determines whether neutropenia management and empagliflozin therapy are needed — a genotype-specific treatment decision that standard metabolic workup does not resolve.
Empagliflozin for type Ib neutropenia is a breakthrough — but is only indicated with confirmed SLC37A4 genotype
GSD type Ib patients accumulate 1,5-anhydroglucitol-6-phosphate (1,5-AG6P) in neutrophils, causing neutrophil dysfunction and neutropenia. Empagliflozin, by blocking renal glucose reabsorption, lowers circulating 1,5-AG levels and reduces neutrophil 1,5-AG6P accumulation — restoring neutrophil counts and function. Multiple case series demonstrate dramatic improvements in neutropenia, mucosal ulceration, and inflammatory bowel disease symptoms. This therapy is specific to the SLC37A4 translocase defect; G6PC-deficient (type Ia) patients do not accumulate 1,5-AG6P and do not benefit. Molecular genotyping identifies the appropriate candidates.
Hepatic adenomas develop in 50-75% of GSD-I patients — surveillance for malignant transformation requires lifelong imaging
Hepatocellular adenomas (HCA) are a major long-term complication of GSD-I, developing in the majority of patients by adulthood. While most HCA remain benign, malignant transformation to hepatocellular carcinoma (HCC) occurs — requiring regular hepatic imaging (ultrasound, MRI) and alpha-fetoprotein monitoring. Confirmed molecular GSD-I diagnosis ensures that the patient is enrolled in the appropriate hepatic surveillance protocol. Additionally, molecular diagnosis enables carrier testing for siblings and reproductive planning for affected adults.
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.
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.
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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 Glycogen Storage Disease Type I 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.
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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
