title: Use of amnion and placenta in neonatal screening for canine GM1-gangliosidosis and the risk of diagnostic misclassifications.
abstract: BACKGROUND
  A closed breeding colony of Shiba dogs with GM1-gangliosidosis is maintained at Hokkaido University (Sapporo, Japan). Neonatal genotyping is essential to control the breeding colony genetically as an animal model for the human disease.
  
  
  OBJECTIVE
  The purpose of the present study was to determine the utility of amnion and placenta in the neonatal screening or diagnosis for canine GM1-gangliosidosis.
  
  
  METHODS
  Twenty neonatal Shiba dogs of a pedigree with GM1- gangliosidosis were differentiated into 3 genotypes--normal, heterozygous, and affected dogs--by using a previously reported DNA mutation assay. Acid beta-galactosidase activity was measured in amnion and placenta and compared among the 3 genotypes.
  
  
  RESULTS
  The level of beta-galactosidase activity in the amnion of affected dogs was negligible and <2% of the mean activity in normal dogs; there was no significant difference among the 3 genotypes. In placenta, beta-galactosidase activity was significantly different among all the genotypes; however, there was wide overlap in enzyme activity between normal and heterozygous dogs. The level of activity in affected dogs was relatively high and >10% of the mean activity in normal dogs. The DNA mutation assay gave correct information about genotype with genomic DNA extracted from amnion but ambiguous information with DNA from placenta.
  
  
  CONCLUSIONS
  Amnion and placenta were not useful as enzyme sources in neonatal screening in canine GM1-gangliosidosis because of the risk of misdiagnosis. DNA from amnion is applicable as a template for genotyping, whereas placenta should not be used because canine placenta contains maternal cells.
authors.affiliation: Laboratory of Internal Medicine, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan. osam@vetmed.hokudai.ac.jp
authors.forename: Osamu
authors.initials: O
authors.lastname: Yamato
authors.forename: Eun-Og
authors.initials: EO
authors.lastname: Jo
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Satoh
authors.forename: Toyofumi
authors.initials: T
authors.lastname: Yamauchi
authors.forename: Asogi
authors.initials: A
authors.lastname: Kobayashi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yamasaki
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Maede
mesh_terms: D000650:Amnion / Q000201:enzymology*; D000818:Animals; D000831:Animals, Newborn; D003951:Diagnostic Errors / Q000662:veterinary*; D004283:Dog Diseases / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D004285:Dogs; D016537:Gangliosidosis, GM1 / Q000175:diagnosis / Q000235:genetics / Q000662:veterinary*; D005838:Genotype; D010375:Pedigree; D010920:Placenta / Q000201:enzymology*; D012306:Risk; D014470:Umbilical Cord; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D001616:beta-Galactosidase