title: Clinical, radiologic, and genetic features of Korean patients with Mucopolysaccharidosis IVA.
abstract: OBJECTIVE
  Mucopolysaccharidosis IVA (MPS IVA; Morquio A syndrome) is rare lysosomal storage disorder caused by N-acetylgalactosamine-6-sulfatase (GALNS) deficiency. Only a few MPS IVA cases have been reported in the Korean literature; there is a paucity of research about clinical or radiologic findings for this disorder. Therefore, we studied clinical findings, radiological features, and genetic data of Korean MPS IVA patients for determining factors that may allow early diagnosis and that may thus improve the patients' quality of life.
  
  
  METHODS
  MPS IVA was confirmed via assay for enzymatic activity of leukocytes in 10 patients. The GALNS gene was analyzed. Patients' charts were retrospectively reviewed for obtaining clinical features and evaluated for radiological skeletal surveys, echocardiography, pulmonary function test, and ophthalmologic test results.
  
  
  RESULTS
  Nine patients had severe clinical phenotype, and 1 had an intermediate phenotype, on the basis of clinical phenotype criteria. Radiologic findings indicated skeletal abnormalities in all patients, especially in the hips and extremities. Eight patients had an odontoid hypoplasia, and 1 showed mild atlantoaxial subluxation and cord myelopathy. Genetic analysis indicated 10 different GALNS mutations. Two mutations, c.451C>A and c.1000C>T, account for 37.5% (6/16) and 25% (4/16) of all mutations in this samples, respectively.
  
  
  CONCLUSIONS
  An understanding of the clinical and radiological features involved in MPS IVA may allow early diagnosis of MPS IVA. Adequate evaluations and therapy in the early stages may improve the quality of life of patients suffering from skeletal abnormalities and may reduce life-threatening effects of atlantoaxial subluxation.
authors.affiliation: Department of Pediatrics, Samsung Medical Center, Sunkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Na Hee
authors.initials: NH
authors.lastname: Lee
authors.forename: Sung Yoon
authors.initials: SY
authors.lastname: Cho
authors.forename: Se Hyun
authors.initials: SH
authors.lastname: Maeng
authors.forename: Tae Yeon
authors.initials: TY
authors.lastname: Jeon
authors.forename: Young Bae
authors.initials: YB
authors.lastname: Sohn
authors.forename: Su Jin
authors.initials: SJ
authors.lastname: Kim
authors.forename: Hyung-Doo
authors.initials: HD
authors.lastname: Park
authors.forename: Dong Kyu
authors.initials: DK
authors.lastname: Jin