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MN Huang, CK Kasper, HR Roberts, DW Stafford and KA High
Department of Medicine, University of North Carolina, Chapel Hill 27599.
A genomic DNA library and the enzymatic DNA amplification technique were
used to isolate human factor IX coding sequences of a hemophilia Bm
variant, factor IXHilo. A point mutation that resulted in the substitution
of a glutamine (CAG) for an arginine (CGG) at amino acid 180 was found in
exon VI of the factor IX gene (G----A at nucleotide 20519). This mutation
alters the carboxy terminal cleavage site for the activation peptide at
Arg180-Val181. The arginine residue at the activation peptide cleavage site
is conserved in mouse, canine, bovine, and human factor IX, suggesting that
the arginine at amino acid 180 is important for normal cleavage. Sequencing
of all of the coding regions of factor IXHilo revealed no other mutations.
We have also shown that the point mutation in exon VI creates a new Dde I
restriction site, which, in combination with the enzymatic DNA
amplification technique, provides a quick, reliable, and sensitive method
for carrier detection and antenatal diagnosis in affected kindreds. This is
the first report of the molecular defect in a hemophilia Bm patient with a
markedly prolonged ox brain prothrombin time.
This article has been cited by other articles:
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| Copyright © 1989 by American Society of Hematology Online ISSN: 1528-0020 | |||||||||
