Pediatric Radiology > Musculoskeletal > Constitutional Disorders of Bone > Mucopolysaccharidoses


Mucopolysaccharidoses

The mucopolysaccharidoses are a group of lysosomal storage diseases characterized by the accumulation of excess glycosaminoglycans (GAGs). Included in this group of disorders are Hunter, Hurler, Morquio, and Sanfilippo syndromes. Associated skeletal deformities are similar throughout this group of diseases, and are collectively referred to as dysostosis multiplex. These deformities likely occur secondary to the accrual of GAGs in the chondrocytes, resulting in abnormal ossification.

Radiographic features of the mucopolysaccharidoses include:

  • osteopenia
  • thickened calvarium, particularly at the base
  • vertebral body deformities - often oval-shaped with beaking of the anterior cortex (most prominent in lumbar region) - beak at midportion of vertebrae with Morquio syndrome but located more inferiorly with Hurler syndrome; posterior vertebral body scalloping may exist.
  • thickened clavicles and ribs (ribs become narrower posteromedially => "canoe paddle" appearance)
  • scoliosis
  • lordosis
  • pelvis has tall, flared iliac wings and increased acetabular angles (the opposite of achondroplasia)
  • femoral epiphyseal dysplasia => coxa valga
  • hands with proximal tapering of metacarpals and short, stubby phalanges

Radiologic manifestations in mucopolysaccharidoses found in a 2-year-old female with Hurler syndome. A, AP chest radiograph demonstrates thickened short clavicles, wide oar-shaped ribs, and elevation of the right hemidiaphragm likely secondary to recurrent atelectasis. B, Lateral radiograph of the spine shows oval-shaped vertebrae with anteroinferior beaking. C, Radiograph of the right hand reveals diaphyseal widening of the metacarpals, proximal phalanges, and middle phalanges; note the tapered ends of the proximal second through fifth metacarpals. D, Lateral skull radiograph shows a thick calvarium, particularly at the base, with an enlarged J-shaped sella turcica. E, AP radiograph of the pelvis demonstrates small, flared iliac wings with increased acetabular angles.




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