title: Natural history and clinical assessment of Taiwanese patients with mucopolysaccharidosis IVA.
abstract: BACKGROUND
  Mucopolysaccharidosis IVA (MPS IVA) is a rare lysosomal storage disorder caused by N-acetylgalactosamine-6-sulfatase deficiency, which catalyzes a step in the catabolism of glycosaminoglycans, keratan sulfate and chondroitin-6-sulfate. This disease has a variable age of onset and rate of progression.
  
  
  METHODS
  A retrospective analysis of medical records of 24 patients with MPS IVA (11 males, 13 females; current mean age ± SD, 12.6 ± 6.6 years; age range, 1.4-29.4 years) seen at 6 medical centers in Taiwan from January 1996 through June 2013 was performed.
  
  
  RESULTS
  Mean ages of onset of symptoms and confirmed diagnosis were 2.0 ± 1.6 and 5.7 ± 4.5 years, respectively. The most prevalent clinical manifestations were kyphosis (100%), pectus carinatum (96%), abnormal gait (93%), striking short trunk dwarfism (92%), genu valgum (92%), and valvular heart disease (91%). Eight patients (33%) experienced at least one surgical procedure with the most common being ear tube insertion (25%), adenoidectomy (17%), tonsillectomy (13%), supraglottoplasty (13%), spinal decompression (13%), and spinal fusion (13%). The most prevalent cardiac valve abnormalities were aortic stenosis (45%) and mitral regurgitation (45%). At the time of the study, 8 out of 24 patients (33%) have died at the mean age of 17.2 ± 7.7 years.
  
  
  CONCLUSIONS
  An understanding of the natural history involved in MPS IVA may allow early diagnosis of the disease. All affected Taiwanese patients experienced significant functional limitations. Adequate evaluations and timely management may improve clinical outcomes and quality of life.
authors: Hsiang-Yu
authors: HY
authors: Lin
authors: Chih-Kuang
authors: CK
authors: Chuang
authors: Ming-Ren
authors: MR
authors: Chen
authors: Pao Chin
authors: PC
authors: Chiu
authors: Yu-Yuan
authors: YY
authors: Ke
authors: Dau-Ming
authors: DM
authors: Niu
authors: Fuu-Jen
authors: FJ
authors: Tsai
authors: Wuh-Liang
authors: WL
authors: Hwu
authors: Ju-Li
authors: JL
authors: Lin
authors: Department of Medicine, Mackay Medical College, New Taipei City, Taiwan. zsplin14@gmail.com.
authors: Shuan-Pei
authors: SP
authors: Lin
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009085:Mucopolysaccharidosis IV / Q000175:diagnosis* / Q000401:mortality; D012189:Retrospective Studies; D055815:Young Adult