Gaucher and Niemann-Pick diseases--enzymatic diagnosis in dried blood spots on filter paper: retrospective diagnoses in newborn-screening cards.
BACKGROUND
Gaucher disease (GD) and Niemann-Pick (NP) disease are caused by deficient activity of the lysosomal enzymes acid beta-D-glucosidase (ABG) and acid sphingomyelinase (ASM), respectively. For diagnosis, these enzymes are usually measured in the extracts of leukocytes or cultured fibroblasts. Chitotriosidase (CTE), a chitinolytic enzyme, is markedly increased in the plasma of Gaucher patients. We describe methods for the assay of acid beta-D-glucosidase, acid sphingomyelinase, chitotriosidase, and alpha-N-acetyl-galactosaminidase (NAGA) as a control enzyme in blood spots that were dried onto filter paper.


METHODS
To tubes containing a 3 mm-diameter blood spot, we added elution liquid and substrate solution. After incubation at 37 degrees C, the amount of hydrolyzed product was compared with a calibrator to allow the quantification of enzyme activity. We examined 80 healthy controls, 54 Gaucher patients, 8 Niemann-Pick patients, 27 obligate carriers, and the newborn-screening cards (NSC) from a case of Gaucher and a case of Niemann-Pick disease.


CONCLUSIONS
The described methodology is useful to identify Gaucher and Niemann-Pick patients and controls, using samples that are sufficiently stable to be transported to the testing laboratory by mail. The diagnosis of both diseases on a newborn-screening card was clearly established. The newborn-screening card has been added to the biological materials that allow the identification of patients with Gaucher and Niemann-Pick diseases.
Chamoles
Néstor A
NA
Laboratory of Neurochemistry, Uriarte 2383, 1425, Buenos Aires, Argentina. nachamoles@fibertel.com.ar
Blanco
Mariana
M
Gaggioli
Daniela
D
Casentini
Carina
C
D000293:Adolescent; D000328:Adult; D001681:Biological Assay / Q000379:methods; D001800:Blood Specimen Collection / Q000379:methods; D002648:Child; D002675:Child, Preschool; D005260:Female; D005776:Gaucher Disease / Q000175:diagnosis*; D005962:Glucosylceramidase / Q000097:blood*; D006596:Hexosaminidases / Q000097:blood*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D015997:Neonatal Screening / Q000379:methods; D009542:Niemann-Pick Diseases / Q000175:diagnosis*; D012189:Retrospective Studies; D013108:Sphingomyelin Phosphodiesterase / Q000097:blood*; D048809:alpha-N-Acetylgalactosaminidase
D013108:Sphingomyelin Phosphodiesterase; D006596:Hexosaminidases; C086400:chitotriosidase; D005962:Glucosylceramidase; C482722:NAGA protein, human; D048809:alpha-N-Acetylgalactosaminidase