Protein C and protein S assessment in hospital laboratories: which strategy and what role for DNA sequencing?
This paper presents a critical assessment of protein C (PC) and protein S (PS) functional and immunological approaches with regard to DNA sequencing in a large hospital recruitment for thrombosis exploration in more than 1700 consecutive patients. After examination of clinical status and PC and PS phenotype, a genotypic study was implemented for 17 PC-deficient and 28 PS-deficient patients (activity < 70%). Sixty-five percent of the genotyped PC-deficient patients were found to have heterozygous mutations. Among the < 70% values, decreases in PC activity without gene mutation were always slight (mean value 64 +/- 7%) while patients presenting a PC gene mutation had a mean 50 +/- 17% activity (P < 0.05). Among the eight PC mutations found, only one has previously been described. A novel mutation in the promoter region (-1522), located in the HNF-1 site and associated with the Y226H heterozygous mutation, was found in a 9-month-old girl with 4% PC activity. Determination of PS functional activity was considerably improved by contemporaneous measurement of calibration and samples in a single step. Only 50% of the genotyped PS-deficient patients demonstrated heterozygous alterations of the gene. The benefit of sequencing to identify putative causal mutations was only 39% in PS-deficient women, while it was 90% in men. Among the nine PS mutations found, six have not yet been published. In the present paper, we explain our methodological choices and diagnostic strategy.
Labrouche
Sylvie
S
Laboratoire d'Hématologie, E.A.482 Université de Bordeaux 2 and Hôpital Pellegrin, Bordeaux, France.
Reboul
Marie-Pierre
MP
Guérin
Viviane
V
Vergnes
Christine
C
Freyburger
Geneviève
G
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D007755:Laboratories, Hospital; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010641:Phenotype; D011401:Promoter Regions, Genetic / Q000235:genetics; D011486:Protein C / Q000235:genetics* / Q000378:metabolism; D020151:Protein C Deficiency / Q000145:classification / Q000235:genetics; D017293:Protein S / Q000235:genetics* / Q000378:metabolism; D018455:Protein S Deficiency / Q000145:classification / Q000235:genetics; D017422:Sequence Analysis, DNA; D012737:Sex Factors; D013927:Thrombosis / Q000235:genetics*
D011486:Protein C; D017293:Protein S