Fluorometric assay of alpha-L-iduronidase in serum for detection of affected and carrier animals in a canine model of mucopolysaccharidosis I.

We investigated measuring serum alpha-L-iduronidase (EC 3.2.1.76) by a sensitive fluorometric assay in 28 members of a canine family with mucopolysaccharidosis I. If assayed on the day of collection, serum was an acceptable specimen for identifying affected, carrier, and normal dogs. The overall correlation (r) between iduronidase activity in serum and mononuclear leukocytes was 0.966. However, iduronidase was extremely labile in serum refrigerated or frozen for 48 h.