Inclusion Criteria (Mothers):

• The patient must have a documented laronidase deficiency with a fibroblast, plasma, serum, leukocyte, or dried blood spot laronidase enzyme activity assay.
• Be pregnant, planning to breastfeed post-partum, and receiving Aldurazyme (laronidase) therapy while breastfeeding.
• Provide signed, written informed consent prior to any protocol-related procedures. Consent of a legally authorized guardian(s) is (are) required for mothers younger than 18 years of age. If a mother is under 18 years old and can understand the consent, written informed consent is required from both the mother and the authorized guardian(s).
• Provide signed, written informed consent for their infants to participate as study patients. If a mother is younger than 18 years of age, consent for mother and infant will be obtained from the legal guardian.

Exclusion Criteria (Mothers and Infants):

• Have a medical condition, serious intercurrent illness, or other extenuating circumstance that may interfere with study compliance, including all prescribed evaluations and follow-up activities.
• Have received an investigational drug within 30 days prior to study enrollment