title: Chitotriosidase Activity and Gene Polymorphism in Iranian Patients with Gaucher Disease and Sibling Carriers.
abstract: OBJECTIVE
  Chitotriosidase (CT) activity is a useful biomarker for diagnosis and monitoring of Gaucher disease (GD). Its application is limited by some variants in the CT gene. Two main polymorphisms are 24 bp duplication and G102S led to reduce CT activity. The aim of this study was to determine these variants influencing on plasma CT activity.
  
  
  METHODS
  Blood samples were collected from 33 patients with GD, 15 sibling carriers and 105 healthy individuals serving as controls. CT activity was measured using 4-methylumbelliferyl-β-D-N,N',N″triacetylchitotrioside substrate in plasma samples. The CT genotypes of 24 bp duplication and G102S variants were determined using PCR and PCR-RFLP.
  
  
  RESULTS
  Untreated GD patients had a significantly higher CT activity compared to treated patients (P = 0.021). In addition, chitotriosidase activity in carriers was higher rather than controls. Allele frequencies of 24 bp duplication in GD patients, sibling carriers and controls were 0.21, 0.266 and 0.29 and for G102S were 0.318, 0.366 and 0.219, respectively. Different G102S genotypes had not significant effect on CT activity. Chitotriosidase activity has a positive correlation with age in normal group, carriers, and negative correlation with hemoglobin in GD patients. Using cut-off level of 80.75 nmol/ml/h, sensitivity and specificity of CT activity were 93.9% and 100%, respectively.
  
  
  CONCLUSIONS
  Chitotriosidase activity is a suitable biomarker for diagnosis and monitoring of GD. Determination of 24 bp duplication is helpful for more accurate monitoring the GD patient's therapy. However, it seems that, specifying of the G102S polymorphism is not required for Iranian GD patients.
authors.affiliation: Department of Clinical Biochemistry, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: Hadi
authors.initials: H
authors.lastname: Mozafari
authors.affiliation: Department of Clinical Biochemistry, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Taghikhani
authors.affiliation: Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: Shohreh
authors.initials: S
authors.lastname: Khatami
authors.affiliation: Department of Pediatric, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Alaei
authors.affiliation: Department of Clinical Biochemistry, Medical School, Kermanshah University of Medical Sciences, Kermanshah, Iran.
authors.forename: Asad
authors.initials: A
authors.lastname: Vaisi-Raygani
authors.affiliation: Department of Clinical Biochemistry, Medical School, Kermanshah University of Medical Sciences, Kermanshah, Iran.
authors.forename: Zohreh
authors.initials: Z
authors.lastname: Rahimi
keywords: 24 bp Duplication; Chitotriosidase; Gaucher Disease; PCR-RFLP; Polymorphism