title: Differential expression of proteins in monozygotic twins with discordance of infantile esotropic phenotypes.
abstract: OBJECTIVE
  To identify strabismus-related proteins, we performed proteome analysis in monozygotic twins with discordance of congenital esotropic phenotypes and in normal children.
  
  
  METHODS
  Surface-enhanced laser desorption/ ionization time-of-flight mass spectrometry (SELDI-TOF-MS) technology was used to detect changes in protein expression in a pair of twins with discordant esotropic phenotypes (twin A is orthotropic and twin B is esotropic). In addition, two non-twin esotropic children and two orthotropic children of the same age were chosen. The differentially expressed proteome obtained was validated in twelve non-twin esotropic children and eighteen orthotropic children and compared to the protein database.
  
  
  RESULTS
  We detected four differentially expressed proteins in monozygotic twins with discordance of congenital esotropic phenotypes. The corresponding molecular weights were 4,146 Da, 4,801 Da, 7,786 Da, and 5,859 Da, respectively. Among these 4 proteins, the first three proteins were down-regulated and the last was upregulated. The initial characterization of these detected proteins via protein library revealed that their characteristics were similar to those of the glucagon precursor, pituitary adenylate cyclase-activating polypeptide (PACAP), camp-dependent protein kinase inhibitor α, and anti-metastasis gene (antigen), respectively.
  
  
  CONCLUSIONS
  There were differentially expressed proteins between monozygotic twins with discordance of congenital esotropic phenotypes and normal children. These differentially expressed proteins were mainly down-regulated in the strabismus patients and may be involved in the occurrence and development of congenital esotropia.
authors: Department of Ophthalmology, the Affiliated Hospital of Medical College, Qingdao University, Qingdao, China. guixiang_liu@126.com
authors: Guixiang
authors: G
authors: Liu
authors: Haiqing
authors: H
authors: Bai
authors: Zhiyong
authors: Z
authors: Yan
authors: Yuna
authors: Y
authors: Ma
authors: Hui
authors: H
authors: Li
mesh_terms: D016022:Case-Control Studies; D002675:Child, Preschool; D002681:China; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics* / Q000378:metabolism; D004200:Diseases in Twins / Q000235:genetics / Q000473:pathology; D015536:Down-Regulation; D004948:Esotropia / Q000235:genetics* / Q000473:pathology; D005123:Eye / Q000473:pathology*; D020869:Gene Expression Profiling; D005838:Genotype; D006801:Humans; D008297:Male; D008970:Molecular Weight; D010641:Phenotype; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000235:genetics* / Q000378:metabolism; D052336:Proglucagon / Q000235:genetics* / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics* / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013285:Strabismus / Q000235:genetics* / Q000473:pathology; D014430:Twins, Monozygotic / Q000235:genetics*
chemical_list: C495401:ADCYAP1 protein, human; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D018809:Proliferating Cell Nuclear Antigen; D052336:Proglucagon; D017868:Cyclic AMP-Dependent Protein Kinases