Detection of new polymorphic markers in the factor V gene: association with factor V levels in plasma.
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Lunghi B, Iacoviello L, Gemmati D, Dilasio MG, Castoldi E, Pinotti M, Castaman G, Redaelli R, Mariani G, Marchetti G, Bernardi F
Detection of new polymorphic markers in the factor V gene: association with factor V levels in plasma.
Thromb Haemost. 1996 Jan;75(1):45-8.
- PubMed ID
- 8713778 [ View in PubMed]
- Abstract
Three novel polymorphisms were found in the repeated region of the large exon 13 of factor V gene, one giving rise to a codon dimorphism (Ser1240) and two causing aminoacid substitutions (His1299Arg, Leu1257Ile). An increasing frequency of the Arg1299 (R2 allele) correlated with a decreasing mean plasma factor V activity in the groups of subjects under study, which included 26 unrelated subjects with partial factor V deficiency. Family studies supported the co-inheritance both of low factor V activity and of R2 allele. The reduction of factor V activity associated with the R2 allele was not clinically symptomatic even in the homozygous condition and was characterized by a parallel reduction of antigen in plasma, in which abnormal molecules were not detected. Data suggest that the R2 allele represents a marker in linkage with an unknown defect rather than a functional polymorphism. These studies provide the first evidence of a genetic component in determining factor V levels in plasma and of a genetic linkage between the factor V gene and factor V deficiency. They also define specific haplotypes which are associated with factor V deficiency or with APC resistance (Arg506Gln) and are valuable tools for the study of factor V defects.