title: Beta-galactosidase deficiencies and novel GLB1 mutations in three Chinese patients with Morquio B disease or GM1 gangliosidosis.
abstract: BACKGROUND
  This paper aims to report GLB1 activities and mutation analysis of three patients from the mainland of China, one with Morquio B disease and two with GM1 gangliosidosis.
  
  
  METHODS
  GLB1 activity and GLB1 gene mutation were analyzed in the three patients who were clinically suspected of having Morquio B disease or GM1 gangliosidosis. Novel mutations were analyzed by aligning GLB1 homologs, 100 control chromosomes, and the PolyPhen-2 tool.
  
  
  RESULTS
  The enzymatic activity of GLB1 was found to be 5.03, 4.20, and 4.50 nmol/h/mg in the three patients, respectively. Patient 1 was a compound heterozygote for p.[Arg148Cys] and p.[Tyr485Cys] mutations in the GLB1 gene. Patient 2 was a compound heterozygote for p.[Tyr270Phe] and p.[Leu337Pro] mutations. Patient 3 was a homozygote for p.[Asp448Val] mutation. Three mutations (p.[Tyr485Cys], p.[Tyr270Phe] and p.[Leu337Pro]) were novel variants and were predicted to damage GLB1 function.
  
  
  CONCLUSIONS
  The enzymatic activity and related gene analysis of β-galactosidase should be performed in clinically suspected individuals to confirm diagnosis. The three novel mutations, p.[Tyr485Cys], p.[Tyr270Phe], and p.[Leu337Pro], are thought to be disease-causing mutations.
authors.affiliation: Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, China.
authors.forename: Hong-Lin
authors.initials: HL
authors.lastname: Lei
authors.forename: Jun
authors.initials: J
authors.lastname: Ye
authors.forename: Wen-Juan
authors.initials: WJ
authors.lastname: Qiu
authors.forename: Hui-Wen
authors.initials: HW
authors.lastname: Zhang
authors.forename: Lian-Shu
authors.initials: LS
authors.lastname: Han
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.forename: Xue-Fan
authors.initials: XF
authors.lastname: Gu
mesh_terms: D000293:Adolescent; D002675:Child, Preschool; D002811:Chondroitinsulfatases / Q000378:metabolism; D004252:DNA Mutational Analysis; D017809:Fatal Outcome; D016537:Gangliosidosis, GM1 / Q000201:enzymology / Q000453:epidemiology / Q000235:genetics*; D006801:Humans; D008297:Male; D049328:Mongolian Spot / Q000453:epidemiology; D009085:Mucopolysaccharidosis IV / Q000201:enzymology / Q000453:epidemiology / Q000235:genetics*; D009154:Mutation; D012878:Skin Neoplasms / Q000453:epidemiology; D001616:beta-Galactosidase / Q000235:genetics*
chemical_list: D002811:Chondroitinsulfatases; C491158:Galns protein, mouse; C061901:GLB1 protein, human; D001616:beta-Galactosidase