Diagnosis of congenital disorders of glycosylation type-I using protein chip technology.

Abstract

A method for the diagnosis of the congenital disorders of glycosylation type I (CDG-I) by SELDI-TOF-MS of serum transferrin immunocaptured on protein chip arrays is described. The underglycosylation of glycoproteins in CDG-I produces glycoforms of transferrin with masses lower than that of the normal fully glycosylated transferrin. Immobilisation of antitransferrin antibodies on reactive-surface protein chip arrays (RS100) selectively enriched transferrin by at least 100-fold and allowed the detection of patterns of transferrin glycoforms by SELDI-TOF-MS using approximately 0.3 microL of serum/plasma. Abnormal patterns of immunocaptured transferrin were detected in patients with known defects in glycosylation (CDG-Ia, CDG-Ib, CDG-Ic, CDG-If and CDG-Ih) and in patients in whom the basic defect has not yet been identified (CDG-Ix). The correction of the N-glycosylation defect in a patient with CDG-Ib after mannose therapy was readily detected. A patient who had an abnormal transferrin profile by IEF but a normal profile by SELDI-TOF-MS analysis was shown to have an amino acid polymorphism by sequencing transferrin by quadrupole-TOF MS. Complete agreement was obtained between analysis of immunocaptured transferrin by SELDI-TOF-MS and the IEF profile of transferrin, the clinical severity of the disease and the levels of aspartylglucosaminidase activity (a surrogate marker for the diagnosis of CDG-I). SELDI-TOF-MS of transferrin immunocaptured on protein chip arrays is a highly sensitive diagnostic method for CDG-I, which could be fully automated using microtitre plates and robotics.

• Authors: Kevin Mills, Philippa Mills, Marie Jackson, Viki Worthington, Clare Beesley, Anúska Mann, Peter Clayton, Stephanie Grunewald, Geoffrey Keir, Liz Young, James Langridge, Nasi Mian, Bryan Winchester
• Journal: Proteomics (Proteomics) Vol. 6 Issue 7 Pg. 2295-304 (Apr 2006) ISSN: 1615-9853 [Print] Germany
• PMID: 16552784 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Glycoproteins
• Transferrin

Topics

• Amino Acid Sequence
• Carbohydrate Metabolism, Inborn Errors (blood, diagnosis, genetics)
• Electrophoresis, Gel, Two-Dimensional
• Glycoproteins (blood)
• Glycosylation
• Humans
• Molecular Sequence Data
• Polymorphism, Genetic
• Protein Array Analysis (methods)
• Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
• Transferrin (analysis, genetics, metabolism)