Hurler Syndrome
New Hurler syndrome research, summarized each month in plain language.
2026 so far: So far in 2026 (January 2026 to September 2026), HSCT and IV enzyme therapy showed measurable biomarker effects but did not eliminate local complications, and early CNS gene therapy signals were mixed and based on single cases. Read the 2026 review
We also cover clinical trials.
Yearly update
2026 so far
- CSF markers and treatment. CSF biomarkers linked ERT timing and HCT effects.
- Newer gene approaches. Single-case gene therapy reports added both feasibility and risk signals.
- Bones and hands. Reports emphasized recurring hand issues and workable leg-alignment surgery.
- Getting the diagnosis right. More emphasis on confirmatory testing and consistent variant interpretation.
- Nerves and breathing. Small studies suggested progression signals needing longer-term monitoring.
New
September 2026
- Blood smear clue. A routine blood smear prompted targeted MPS I testing.
- Enzyme and gene results. Low enzyme activity and IDUA changes supported MPS I.
- Laronidase treatment. In one child, laronidase was linked to steadier body symptoms.
- Breathing changes. In this case, breathing symptoms improved after treatment started.
August 2026
- Sibling transplant effect. A matched-sibling transplant restored enzyme activity to normal.
- Urine marker change. A urine disease marker fell and stayed stable for a year.
- Breathing support. Short-term ventilation was needed, then breathing improved.
July 2026
- Patchy lung airflow. In mice, airflow varied across the lungs.
- Airways and lung tissue. Mouse data suggested airway narrowing plus lung tissue changes.
- Unusual HSCT complication. One HSCT death involved bowel wall gas and lung air bubbles.
June 2026
- Knock-knee correction. Guided growth plates corrected knock-knees at a typical pace.
- Screening test materials. Newborn screening quality-check materials showed very high accuracy.
- Oral enzyme testing. An oral enzyme helped in lab and mice, not yet in people.
May 2026
- CSF markers fell with treatment. Spinal-fluid (CSF) storage markers were lower with IV enzyme therapy and were also reported to drop after transplant.
- After transplant: no further CSF drop. In one cohort, long-term IV enzyme therapy after transplant did not lower CSF markers further than transplant alone.
- Clearer genetic diagnosis. Broader genetic testing plus enzyme testing helped explain some hard-to-diagnose cases.
- RNA enzyme boosting (mouse data). An RNA-based approach increased IDUA enzyme activity in mice, but this has not been proven in people.
April 2026
- Brain gene therapy (single case). In one child, brain-targeted RGX-111 gene therapy was followed by stable brain imaging over years, with side effects described as mild.
- Trigger digits in children. Trigger digits were reported as common in children with MPS I and sometimes returned after surgery.
- Newborn screening follow-up. In one screening program, early positive newborn screens for MPS I did not confirm after follow-up testing.
March 2026
- Second screening test. Adding a second newborn blood-spot test for glycosaminoglycans (GAGs) was linked to a higher share of confirmed cases being labeled severe MPS I.
- Carpal tunnel over time. Carpal tunnel syndrome often begins in early childhood in Hurler syndrome and can return after surgical release.
- Animal treatment studies. Two mouse studies increased IDUA activity and reduced GAG buildup, but these results are not yet proven in people.
February 2026
- Nerve tests changed over years. In a very small treated group, repeated arm and hand nerve tests shifted in a worse direction over several years, showing that nerve function can continue to change over time.
- Median nerve affected more. The median nerve showed more change than the ulnar nerve, which matches a carpal tunnel–type pattern and links nerve testing to hand symptoms.
January 2026
- IDUA variant range. Brazil data added more IDUA gene variants in MPS I.
- Regional variant patterns. Common IDUA variants differed between Brazil and India.
- Biobank-linked records. A national biobank linked samples and results for steadier diagnosis.
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