Hybridization studies of fibroblasts from Hurler, Scheie, and Hurler/Scheie compound patients: support for the hypothesis of allelic mutants.

Heterokaryons were made by fusion of alpha-L-iduronidase-deficient fibroblasts from patients with the Hurler, Scheie, or Hurler/Scheie compound syndrome. The fused cell populations remained alpha-L-iduronidase deficient and accumulated 35S-labeled glycosaminoglycans (35S-GAG) to the same extent as the parental cells strains. Also, when 35S-GAG accumulation was studied by autoradiography at the level of single bi- and multinuclear hybrid cells, no evidence was found for genetic complementation. The results support the hypothesis that the mutations in the Hurler and Scheie syndromes are allelic, and they are compatible with the view that patients with intermediate phenotypes represent genetic compounds.