Hemophilia A due to mutations that create new N-glycosylation sites

Ashraf M. Aly, Miyoko Higuchi, Carol K. Kasper, Haig H. Kazazian, Stylianos E. Antonarakis, Leon W. Hoyer

Research output: Contribution to journalArticlepeer-review

45 Scopus citations


In studying the molecular defects responsible for cross-reacting material-positive hemophilia A, we have identified two patients in whom the nonfunctional factor VIII-like protein has abnormal, slower-moving heavy or light chains on SDS/PAGE. Both patients have severe hemophilia A (<1% of normal factor VIII activity) with a normal plasma level of factor VIII antigen. The molecular defects were identified by denaturing gradient gel electrophoresis screening of PCR-amplified products of the factor VIII-coding DNA sequence followed by nucleotide sequencing of the abnormal PCR products. In patient ARC-21, a methionine-to-threonine substitution at position 1772 in the factor VIII light chain creates a potential new N-glycosylation site at asparagine-1770. In patient ARC-22, an isoleucine-to-threonine substitution at position 566 creates a potential new N-glycosylation site at asparagine-564 in the A2 domain of the factor VIII heavy chain. The mobility of these chains on SDS/PAGE was normal after N-Glycanase digestion and procoagulant activity was generated - to a maximum of 23% and 45% of control normal plasma. Abnormal N-glycosylation, blocking factor VIII procoagulant activity, represents a newly recognized mechanism for the pathogenesis of severe hemophilia A.

Original languageEnglish (US)
Pages (from-to)4933-4937
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number11
StatePublished - 1992
Externally publishedYes


  • Denaturing gradient gel electrophoresis
  • Factor VIII
  • N-glycanase

ASJC Scopus subject areas

  • General


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