Homozygous mice are viable but have reduced neonatal survival. Homozygotes are infertile, but fertility can be restored with enzyme replacement therapy. No residual enzyme activity is observed. Homozygous mice are indistinguishable from heterozygous and wild type mice at birth, but show distinct growth retardation, shortened extremities, and facial dysmorphism observable at wean and increasing in severity with age. Long bones of the lower extremities are shortened, broad, and sclerotic. Compared to wild-type, this model has increased urinary glycosaminoglycan and secondary elevation of other lysosomal storage enzymes. Further, homozygous mice show abundant lysosomal storage in liver, kidney, leptomeningeal cells, cornea, spleen, neurons, and retinal pigment epithelium. The phenotype exhibited by this mutant mouse strain is more severe than that observed in a similarly constructed mutant (Stock No. 005644) which bears a L175F point mutation. This strain represents a model of human GUS deficiency characterized by the human E540A mutation that may be useful in studies of severe Mucopolysaccharidosis type VII (MPS VII or Sly Syndrome).
