Alpha-L-iduronidase is encoded by the IDUA gene. Pathogenic mutations to the IDUA gene lead to a defective α-L-iduronidase enzyme with less than normal enzyme activity.1 A definitive diagnosis is established by:
- α-L-iduronidase enzyme activity assay: demonstrating absence or deficiency (does not allow for differentiation between severe and attenuated)1
- IDUA gene sequencing: demonstrating 2 pathogenic variants in trans (one from each parent). Though identification of mutant alleles may not be required for diagnosis, sequencing the IDUA gene can provide secondary confirmation after enzymatic testing and can provide important information related to phenotype1
For more information on diagnosing MPS I, including a list of labs offering IDUA gene sequencing or α-L-iduronidase enzyme activity assay,
This is not an exhaustive list of labs, or an endorsement of any one lab. Other testing options can be found at https://www.concertgenetics.com (free login required) or https://www.ncbi.nlm.nih.gov/gtr. Sanofi does not review or control the content of non-Sanofi websites. These listings do not constitute an endorsement by Sanofi of information provided by any other organizations. Tests may not be available in all states. Please contact the laboratory to confirm test availability, sample shipping information, and all other logistics.
MPS I Diagnostic Delay
Patients typically are referred to several specialists before they are correctly diagnosed. Misdiagnoses and diagnostic delays are common, especially in attenuated MPS I.
Recommended Minimum Evaluation Schedule
For a list of recommendations on a minimum evaluation schedule obtained from peer-reviewed publications. Physicians and other healthcare providers will determine the assessments and their actual frequency according to the patient’s individual needs,