Onset in 1st few months of life of physical and mental deterioration; marked by grotesque facial features, hydrocephalus, hirsutism, dwarfism, chest anomalies, retinal degeneration, and hepatosplenomegaly. Cause is deficiency in alpha-1-iduronidase with impaired degradation of heparan and dermatan sulfate. Death usu. occurs by 10 years of age due to cardiac failure and lung infection. Condition is autosomal recessive.