Children with Hunter syndrome are missing a working copy of a single enzyme — iduronate-2-sulfatase (IDS). Below is that exact enzyme, in real 3D, and the plan to give the body a durable source of it again.
This is the real, experimentally-determined structure of human iduronate-2-sulfatase (Protein Data Bank entry 5FQL). Drag to rotate. Toggle to its catalytic core — the chemistry that Hunter syndrome breaks.
Hunter syndrome is caused by mutations in the IDS gene. Without working IDS, large sugar chains called glycosaminoglycans (GAGs) — dermatan sulfate and heparan sulfate — can't be broken down. They accumulate inside cells, progressively damaging tissues throughout the body.
MPS II is one of the mucopolysaccharidoses — "storage" disorders where the cell's recycling center, the lysosome, fills with material it can't clear. Current standard care (weekly enzyme-replacement infusions) helps the body but does not effectively reach the brain and must be given for life.
The goal of Operation Hunter is a durable, self-renewing source of the corrected enzyme — not a lifelong infusion.
Take a patient's own cells, fix the gene, grow them, and seal them inside a tiny protective capsule that acts as a living factory — continuously secreting working IDS while staying hidden from the immune system.
It is also just one of several possible paths to a cure. Some therapies already in research can reach the brain — and a faster route may be to back or help extend one of them. See the current treatment landscape →
Patient skin or blood cells are reprogrammed into induced pluripotent stem cells — a renewable, patient-matched starting material.
CRISPR-Cas9 (delivered as a ribonucleoprotein by nucleofection) plus a repair template fixes the faulty IDS sequence so the cells make functional enzyme.
Single corrected cells are cloned, sequenced (Sanger/NGS), karyotyped for safety, and confirmed to secrete active, formylglycine-modified IDS.
Cells are enclosed in a semipermeable capsule: nutrients in, therapeutic enzyme out — while antibodies and immune cells are kept out.
The capsule is implanted as a living factory, providing a steady, renewable supply of corrected IDS without lifelong infusions.
A semipermeable membrane is tuned by pore size: small molecules — oxygen and nutrients in, the therapeutic enzyme and waste out — pass freely, while large immune components (antibodies, immune cells) are blocked. The cells survive and keep working without systemic immune suppression.
Every piece above exists in the scientific literature. What's missing is the money and coordination to assemble the team. That's what Operation Hunter does.
Educational summary only. Operation Hunter is not a medical provider; this is not medical advice. Any therapy described here would be developed and tested by qualified institutions under FDA/IRB oversight.