[Diagnosis and nosology of glycanosis CDG ("carbohydrate deficient glycoprotein syndrome")].
BACKGROUND
The "Carbohydrate-deficient glycoprotein syndrome" is a recently discovered inborn error of complex carbohydrate metabolism. The disease involves a number of organ systems and various deficient glycoproteins. An abnormal isoform of serum transferrin is of diagnostic value.


METHODS
We analysed the glycoprotein alpha-1-antitrypsin of two affected infants and their clinically healthy parents using high resolution isoelectric focusing technique. Besides normal isoforms of alpha-1-antitrypsin, we found an abnormal cathodic isoform ("CDG-alpha-1-antitrypsin") which represented almost half of the total amount of alpha-1-antitrypsin of the patients.


RESULTS
This new marker-glycoprotein suggests a defect of the production of biantennary and of triantennary N-glycans during an early step of their synthesis, resulting in monoantennary N-glycans. Also this marker-glycoprotein seems to be a specific biochemical diagnostic tool for discovering glycanosis CDG (Carbohydrate-deficient glycoprotein syndrome). The mode of inheritance is probably incomplete autosomal dominant. The same genetic defect of N-glycan synthesis may be present in more than one type of the hybrid molecule glycoprotein, and was also found in transferrin, resembling a "genetic back-pack", that might explain the multitude of clinical symptoms.


CONCLUSIONS
In view of these findings, we present novel systematics of those diseases that are due to inborn errors of N-glycan synthesis, and which we suggest to call "glycanoses".
Heyne
K
K
Institut für Anthropologie und Humangenetik, Universität München.
Weidinger
S
S
D000015:Abnormalities, Multiple / Q000235:genetics*; D002239:Carbohydrate Metabolism, Inborn Errors / Q000175:diagnosis / Q000235:genetics*; D005260:Female; D005819:Genetic Markers / Q000235:genetics; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D007231:Infant, Newborn; D007525:Isoelectric Focusing; D016464:Lysosomal Storage Diseases / Q000175:diagnosis / Q000235:genetics*; D008297:Male; D010641:Phenotype; D011134:Polysaccharides / Q000378:metabolism*; D013577:Syndrome; D000515:alpha 1-Antitrypsin / Q000235:genetics
D005819:Genetic Markers; D006023:Glycoproteins; D011134:Polysaccharides; D000515:alpha 1-Antitrypsin
Diagnostik und Nosologie der Glykanose CDG ("Carbohydrate-deficient glycoproteinsyndrome").