title: Dried blood spots for the enzymatic diagnosis of lysosomal storage diseases in dogs and cats.
abstract: BACKGROUND
  In people, lysosomal storage diseases (LSD) can be diagnosed by assaying enzyme activities in dried blood spots (DBS).
  
  
  OBJECTIVE
  The aim of this study was to evaluate the feasibility of using DBS samples from dogs and cats to measure lysosomal enzymatic activities and diagnose LSD.
  
  
  METHODS
  Drops of fresh whole blood collected in EDTA from dogs and cats with known or suspected LSD and from clinically healthy dogs and cats were placed on neonatal screening cards, dried, and mailed to the Metabolic Laboratory, University Children's Hospital, Frankfurt, Germany. Activities of selected lysosomal enzymes were measured using fluorescent substrates in a 2-mm diameter disk (~2.6 μL blood) punched from the DBS. Results were expressed as nmol substrate hydrolyzed per mL of blood per minute or hour.
  
  
  RESULTS
  Reference values were established for several lysosomal enzyme activities in DBS from dogs and cats; for most enzymes, activities were higher than those published for human samples. Activities of β-glucuronidase, N-acetylglucosamine-4-sulfatase (arylsulfatase B), α-mannosidase, α-galactosidase, α-fucosidase, and hexosaminidase A were measureable in DBS from healthy cats and dogs; α-iduronidase activity was measureable only in cats. In samples from animals with LSD, markedly reduced activity of a specific enzyme was found. In contrast, in samples from cats affected with mucolipidosis II, activities of lysosomal enzymes were markedly increased.
  
  
  CONCLUSIONS
  Measurement of lysosomal enzyme activities in DBS provides an inexpensive, simple, and convenient method to screen animals for suspected LSD and requires only a small sample volume. For diseases in which the relevant enzyme activity can be measured in DBS, a specific diagnosis can be made.
authors.affiliation: Department of Pediatrics, University Children's Hospital, Frankfurt am Main, Germany. adrian.sewell@kgu.de
authors.forename: Adrian C
authors.initials: AC
authors.lastname: Sewell
authors.forename: Mark E
authors.initials: ME
authors.lastname: Haskins
authors.forename: Urs
authors.initials: U
authors.lastname: Giger
mesh_terms: D000818:Animals; D001800:Blood Specimen Collection / Q000662:veterinary; D002371:Cat Diseases / Q000097:blood / Q000175:diagnosis*; D002415:Cats; D004796:Clinical Enzyme Tests / Q000662:veterinary*; D004283:Dog Diseases / Q000097:blood / Q000175:diagnosis*; D004285:Dogs; D059788:Dried Blood Spot Testing / Q000662:veterinary*; D005260:Female; D005858:Germany; D005966:Glucuronidase / Q000097:blood; D054818:Hexosaminidase A / Q000097:blood; D007068:Iduronidase / Q000097:blood; D016464:Lysosomal Storage Diseases / Q000097:blood / Q000175:diagnosis / Q000662:veterinary*; D008247:Lysosomes / Q000201:enzymology; D008297:Male; D020051:N-Acetylgalactosamine-4-Sulfatase / Q000097:blood; D012016:Reference Values; D013045:Species Specificity; D000519:alpha-Galactosidase / Q000097:blood; D005644:alpha-L-Fucosidase / Q000097:blood; D043323:alpha-Mannosidase / Q000097:blood
chemical_list: D020051:N-Acetylgalactosamine-4-Sulfatase; D000519:alpha-Galactosidase; D043323:alpha-Mannosidase; D005966:Glucuronidase; D005644:alpha-L-Fucosidase; D054818:Hexosaminidase A; D007068:Iduronidase