ACR Codes: 1.6
The mucopolysaccharidoses are a recessively inherited group of lyosomal storage disorders of mucopolysaccharide metabolism resulting in a wide variety of skeletal, visceral and mental abnormalities. A deficiency of specific degradable enzymes results in an accumulation of glycosaminoglycans (acid mucopolysaccharides) in various tissues.
Recently mucopolysaccharidoses (MPS) have been classified into seven types.
MPS1-H Hurler Syndrome (Gargoylism): The following synonyms have been used: Lipochondrodystrophy, gargoylism, osteochondrodystrophy, dysostosis multiplex, and Pfaundler-Hurler disease. It is inherited in an autosomal recessive pattern, occurs in approximately 1/10000 births, and is diagnosed in the first years of life. Clinical features are rarely present at birth. Progressive mental and physical deterioration is the rule, and death results at a younger age than in other mucopolysaccharidoses.
Patients reveal a distinctive facies, mental retardation, deafness, dwarfism, corneal opacities, hepatosplenomegaly, cardiomegaly and cardiac murmurs. The hands are trident, with stiff joints, and clawing develops early. There is dorso-lumbar kyphosis.
The diagnosis is confirmed biochemically by the presence of excessive mucopolysacchariduria, dermatan sulphate, heparan sulphate and metachromatic granules (Reilly bodies) in circulating lymphocytes or bone marrow cells and low or absent alpha-L-iduronidase activity in various tissues.
ROENTGENOGRAPHIC FEATURES: The skeletal changes at birth consist of a thick periosteal covering of the diaphysis of long bones, generalized osteoporosis and metaphyseal cupping. Later, changes in tubular bones are most marked in the upper extremities, characteristically with swelling in the central portions and tapering at one or both ends. The tapered articular ends of the radius and ulna face each other. The ribs are wide and tapered at both ends. Lower extremities exhibit less dramatic change, and coxa valga or vera is common. The pelvis is altered by flaring of the iliac wings and tapering of the pubic rami. Radiographs of the skull reveal macrocephaly, craniosynostosis, elongation of the suture digitations, pituitary fossa enlargement but without erosion. The pituitary fossa enlargement may occur without hydrocephalus or pituitary tumor and is the result of the sphenoid bone growth disturbance. The vertebral bodies are ovoid with hypoplasia of the vertebrae in the thoracolumbar junction resulting in kyphosis. Vertebral changes are different from those of Morquio's syndrome. The centra are oval due to a convexity of upper and lower surfaces. The height of the centrum is either increased or normal, in contrast to Morquio syndrome.
Hurler syndrome may be confused with Morquio syndrome, but changes in the spine, skull and long bones help to distinguish the two entities. Morquio's syndrome does not show sellar enlargement, and its central vertebral beaking differs from the inferior beaking of Hurler. Tapering of long bones is less marked in Morquio syndrome; acetabular irregularity is always present but is not prominent in Hurler syndrome.
Dwarfism is common in Hurler syndrome and may be mistaken for achondroplasia, but shortened extremities are not present at birth. The hepatosplenomegaly of Hurler does not occur in either Morquio's syndrome or achondroplasia.
CT of the brain may reveal hydrocephalus that can be progressive, enlargement of the interhemispheric fissures and cortical sulci, and a symmetric low attenuation in the white matter.
MRI reveals delayed or deficient myelination in the brain with improvement after bone marrow transplantation.
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Disease Topic 1560 
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