TY - JOUR
T1 - Missense or splicing mutation? The case of a fibrinogen Bβ-chain mutation causing severe hypofibrinogenemia
AU - Asselta, Rosanna
AU - Duga, Stefano
AU - Spena, Silvia
AU - Peyvandi, Flora
AU - Castaman, Giancarlo
AU - Malcovati, Massimo
AU - Mannucci, Pier Mannuccio
AU - Tenchini, Maria Luisa
PY - 2004/4/15
Y1 - 2004/4/15
N2 - The genetic basis of severe hypofibrinogenemia was analyzed in a 57-year-old Italian woman. She turned out to be a compound heterozygote for a novel putative missense mutation (Leu172Gln) and a previously described nonsense mutation (Arg17Stop) in the fibrinogen Bβ-chain gene. The pathogenetic role of Leu172Gln was analyzed by in vitro expression of the mutant recombinant protein in COS-1 cells. These experiments demonstrated that mutant Bβ-Leu172Gln fibrinogen was normally assembled and secreted. Inspection of the nucleotide sequence surrounding the mutation suggested a possible role on pre-messenger RNA (mRNA) splicing. Production of the mutant transcript in HeLa cells confirmed that the mutation activates a cryptic acceptor splice site in exon 4, resulting in a truncated Bβ chain, lacking approximately 70% of the C-terminal region. This represents the first exonic splicing mutation identified in the fibrinogen genes. These findings strengthen the importance to analyze potentially pathogenetic nucleotide variations at both the protein and the mRNA level.
AB - The genetic basis of severe hypofibrinogenemia was analyzed in a 57-year-old Italian woman. She turned out to be a compound heterozygote for a novel putative missense mutation (Leu172Gln) and a previously described nonsense mutation (Arg17Stop) in the fibrinogen Bβ-chain gene. The pathogenetic role of Leu172Gln was analyzed by in vitro expression of the mutant recombinant protein in COS-1 cells. These experiments demonstrated that mutant Bβ-Leu172Gln fibrinogen was normally assembled and secreted. Inspection of the nucleotide sequence surrounding the mutation suggested a possible role on pre-messenger RNA (mRNA) splicing. Production of the mutant transcript in HeLa cells confirmed that the mutation activates a cryptic acceptor splice site in exon 4, resulting in a truncated Bβ chain, lacking approximately 70% of the C-terminal region. This represents the first exonic splicing mutation identified in the fibrinogen genes. These findings strengthen the importance to analyze potentially pathogenetic nucleotide variations at both the protein and the mRNA level.
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U2 - 10.1182/blood-2003-10-3725
DO - 10.1182/blood-2003-10-3725
M3 - Article
C2 - 15070683
AN - SCOPUS:1842422434
VL - 103
SP - 3051
EP - 3054
JO - Blood
JF - Blood
SN - 0006-4971
IS - 8
ER -