Variant of iduronidase deficient mucopolysaccharidoses: further evidence for genetic heterogeneity.

An alpha-L-iduronidase deficiency syndrome has been described in adult male twins, which was phenotypically distinct from that of the Hurler and Scheie syndromes or the chondroitinsulphaturias. Multiple dysostosis and stiff joints were present without cloudy corneae, cardiac involvement and mental or physical retardation. This clinical phenotype appeared to be a newly recognized allelic mutation at the iduronidase locus but does not exclude a non-allelic mutation coding for a subunit of the iduronidase molecule.