Gertrud Hurler, 1889-1965, Austrian paediatrician first described this disease. It is caused by deficiency of the enzyme deficiency alpha-L-iduronidase. There is excess urinary excretion of dermatan sulphate and heparan sulphate. Clinically, there is severe mental retardation which is progressive. The children have a coarse facies, are short statured, have a protruberant abdomen, hernias, joint contractures and a thoracolumbar gibbus. There is also hepatosplenomegaly, cardiomyopathy and cardiac failure. Radiologically, there is a large skull with a J-shaped sella, shallow orbits, beaking and flattening of the anterior portion of the vertebral bodies at the thoracolumbar junction, wide, thick ribs, thick clavicles, widening of the shafts of the long bones with flaring of relatively small iliac wings with acetabular roofs. All the mucopolysaccharidoses share in common pointing of the bases of the metacarpals.