- Etiology: lysosomal storage disorders which have excessive accumulation of mucopolysaccharides secondary to deficiencies in lysosomal hydrolase enzymes responsible for degradation of mucopolysaccharides
- Imaging:
— Osteopenia
— Enlarged cranium with thickened calvarium
— Anteroinferiorly beaked oval vertebral bodies which are hypoplastic
— Dysplastic capital femoral epiphyses
— Short and wide metacarpals and phalanges that taper proximally – clawlike hand
— Dysostosis multiplex
— Skull
— Large and dolichocephalic
— Poorly developed mastoids and paranasal sinuses
— Elongated J shaped sella turcica
— Malformed teeth
— Thick diploic space
— Spine
— Gibbus deformity at T-L junction due to defective development of anterosuperior portion of vertebral bodies causing central beaking of vertebral bodies
— Vertebral bodies oval and slightly flattened
— Odontoid hypoplasia
— Pelvis
— Superior acetabular region underdeveloped -> widened acetabular roof and high acetabular angle (flared pelvis)
— Coxa valga
— Femoral heads delayed in development and dysplastic
— Chest
— Oar shaped ribs – widened but taper at vertebral margins
— Thick, short, wide clavicles
— Tubular bones
— Short broad bones with diaphyseal and metaphyseal expansion
— Delay in epiphyseal ossification
— Cortical thinning
— Changes more marked in upper than lower extremities
— Constriction of humeral and femoral necks with varus deformities
— Distal portions of radius and ulna taper, altering carpal angle
— Hand
— Diffuse osteopenia, cortical thinning
— Proximal tapering of 2nd – 5th metacarpal bones
— Proximal and middle phalanges short and wide
— Terminal phalanges are hypoplastic
— Carpal bones small and deformed - DDX: Universal platyspondyly unique to Morquio within mucopolysaccharidoses
- Complications:
- Treatment:
- Clinical:
— Is mucopolysaccharidoses Type IV
— Short trunk
— Short stature, lax joints, stiff neck
— Die young
— Have congenital heart disease