title: Mucopolysaccharidosis IVA (Morquio A syndrome) and VI (Maroteaux-Lamy syndrome): under-recognized and challenging to diagnose.
abstract: OBJECTIVE
  Mucopolysaccharidosis IVA (MPS IVA, or Morquio A syndrome) and VI (MPS VI, or Maroteaux-Lamy syndrome) are autosomal recessive lysosomal storage disorders. Skeletal abnormalities are common initial presenting symptoms and, when recognized early, may facilitate timely diagnosis and intervention, leading to improved patient outcomes. Patients with slowly progressing disease and nonclassic phenotypes can be particularly challenging to diagnose. The objective was to describe the radiographic features of patients with a delayed diagnosis of MPS IVA or VI.
  
  
  METHODS
  This was a retrospective study. The records of 5 MPS IVA and 3 MPS VI patients with delayed diagnosis were reviewed. Radiographs were evaluated by a radiologist with special expertise in skeletal dysplasias.
  
  
  RESULTS
  An important common theme in these cases was the appearance of multiple epiphyseal dysplasia (MED) with epiphyseal changes seemingly confined to the capital (proximal) femoral epiphyses. Very few patients had the skeletal features of classical dysostosis multiplex.
  
  
  CONCLUSIONS
  Radiologists should appreciate the wide phenotypic variability of MPS IVA and VI. The cases presented here illustrate the importance of considering MPS in the differential diagnosis of certain skeletal dysplasias/disorders, including MED, some forms of spondylo-epiphyseal dysplasia (SED), and bilateral Perthes-like disease. It is important to combine radiographic findings with clinical information to facilitate early testing and accurate diagnosis.
authors.affiliation: International Skeletal Dysplasia Registry, Cedars-Sinai Medical Center/University of California, Los Angeles, Los Angeles, CA, USA, rrlachman@earthlink.net.
authors.forename: Ralph S
authors.initials: RS
authors.lastname: Lachman
authors.forename: Barbara K
authors.initials: BK
authors.lastname: Burton
authors.forename: Lorne A
authors.initials: LA
authors.lastname: Clarke
authors.forename: Scott
authors.initials: S
authors.lastname: Hoffinger
authors.forename: Shiro
authors.initials: S
authors.lastname: Ikegawa
authors.forename: Dong-Kyu
authors.initials: DK
authors.lastname: Jin
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kano
authors.forename: Ok-Hwa
authors.initials: OH
authors.lastname: Kim
authors.forename: Christina
authors.initials: C
authors.lastname: Lampe
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Mendelsohn
authors.forename: Renée
authors.initials: R
authors.lastname: Shediac
authors.forename: Pranoot
authors.initials: P
authors.lastname: Tanpaiboon
authors.forename: Klane K
authors.initials: KK
authors.lastname: White
mesh_terms: D000293:Adolescent; D000328:Adult; D001842:Bone and Bones / Q000000981:diagnostic imaging*; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D009085:Mucopolysaccharidosis IV / Q000000981:diagnostic imaging*; D009087:Mucopolysaccharidosis VI / Q000000981:diagnostic imaging*; D011859:Radiography; D055815:Young Adult