title: Benign FGB (148Lys→Asn, and 448Arg→Lys), and novel causative γ211Tyr→His mutation distinguished by time of flight mass spectrometry in a family with hypofibrinogenaemia.
abstract: We describe a novel procedure for the direct analysis of plasma fibrinogen by HPLC time of flight (TOF) mass spectrometry and apply it to the investigation of a family with hypofibrinogenaemia. Electrospray TOF analysis provided much higher resolution than was possible with our previous quadrupole analyser and revealed three different mass changes within the fibrinogen Bβ and γ chains of the family. It also demonstrated the actual hypofibrinogenaemia phenotype was caused by an aberrantγ chain (-23 Da) which was expressed at a diminished ratio of 0.2:1 relative to γ(A) and co-inherited with a second coequally expressed Bβ variant (Bβ(M) /Bβ(A), 1:1). Co-segregation was confirmed by gene analysis that showed the affected father and son had a very rare Bβ148Lys→Arg mutation (-14 Da) inherited together with a unique new γ211Tyr→His mutation (-26 Da). This latter causative substitution occurs at a site that is absolutely conserved across all fibrinogen chains and preserved across all species. TOF analysis also identified a variant Bβ chain (54,186 Da) that was coequally expressed with normal Bβ chains (54,213 Da) in the unaffected mother.
authors.affiliation: Prof. Stephen Brennan, Molecular Pathology Laboratory, Canterbury Health Laboratories, PO Box 151, Christchurch 8014, New Zealand, Tel.: +64 3 364 0549, Fax: +64 3 364 0545, E-mail: steve.brennan@otago.ac.nz.
authors.forename: Stephen O
authors.initials: SO
authors.lastname: Brennan
authors.forename: Hilda
authors.initials: H
authors.lastname: Mangos
authors.forename: James M
authors.initials: JM
authors.lastname: Faed
mesh_terms: D000347:Afibrinogenemia / Q000151:congenital* / Q000175:diagnosis / Q000235:genetics; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004252:DNA Mutational Analysis; D005190:Family; D005340:Fibrinogen / Q000032:analysis* / Q000235:genetics; D005838:Genotype; D006470:Hemorrhage / Q000175:diagnosis* / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D009154:Mutation / Q000235:genetics; D009520:New Zealand; D010375:Pedigree; D010949:Plasma / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: C115499:BBeta fibrinogen; D005340:Fibrinogen
keywords: Fibrinogen; fibrin; gene expression; gene mutations; inherited coagulation disorders; time of flight MS