DETECTION OF MISSENSE MUTATIONS BY SINGLE-STRAND CONFORMATIONAL POLYMORPHISM (SSCP) ANALYSIS IN 5 DYSFUNCTIONAL VARIANTS OF COAGULATION FACTOR-VII

Five unrelated subjects with dysfunctional coagulation factor VII (FVI I) were studied in order to identify missense mutations affecting func tion. Exons 2 to 8 and the intron-exon junctions of their FVII genes w ere amplified from peripheral white blood cell DNA by PCR and screened by SSCP analysis. DNA fragments showing aberrant mobility were sequen ced. The following mutations were identified: in case 1 (FVII:C < 1%, FVII:Ag 18%) a heterozygous A to G transition at nucleotide 8915 in ex on 6 results in the amino acid substitution Lys-137 to Glu near the C- terminus of the FVIIa light chain; in case 2 (FVII:C 7%, FVII:Ag 47%) a heterozygous A to G transition at nucleotide 7834 in exon 5 results in the substitution of Gln-100 by Arg in the second EGF-like domain; i n case 3 (FVII:C 20%, FVII:Ag 76%) a homozygous G to A transition at n ucleotide position 6055 in exon 4 was detected resulting in substituti on of Arg-79 by Gln in the first EGF-like domain; in case 5 (FVII:C 10 %, FVII:Ag 52%) a heterozygous C to T transition at nucleotide positio n 6054 in exon 4 also results in the substitution of Arg79, but in thi s case it is replaced by Trp; case 4 (FVII:C < 1%, FVII:Ag 100%) was h omozygous for a previously reported mutation (G to A) at nucleotide po sition 10715 in exon 8, substituting Gln for Arg at position 304 in th e protease domain. Cases 1, 2 and 5 evidently have additional undetect ed mutations.