Factor XI (FXI) deficiency is a rare bleeding disorder. Most patients with FXI deficiency are mild bleeders but certain patients with similar FXI activity exhibit different bleeding phenotype. Routine laboratory assays do not help physicians to estimate the individual bleeding risk in these patients. Thrombin generation test (TGT) is a more comprehensive, global function test of the clotting system. We investigated whether or not the bleeding tendency of patients with FXI deficiency is correlated with features of the TGT. Twenty-four patients with FXI deficiency were divided in two groups: (i) severe bleeders (n = 9) and (ii) mild or non-bleeders (n = 15). All severe bleeders had a personal history of surgery-related severe bleeding. Thrombin generation (TG) was measured in platelet-rich plasma (PRP) using a low concentration of tissue factor 0.5 pm. In patients exhibiting severe bleeding tendency, independently of their FXI level, a dramatically impaired TG was observed. For example, despite a low plasma FXI = 1 IU dl(-1), a clinically non-bleeding individual exhibited normal TG results whereas another patient with severe bleeding history and FXI = 40 IU dl(-1) had a very low TG capacity. Low velocity and delayed TG were the main parameters suggesting a higher bleeding risk. DNA analysis of patients reported eight novel mutations of the FXI gene but neither mutation location nor secretion or not of the variant correlated with the bleeding tendency. The results of this study suggest that TG measurement in PRP may be a useful tool to predict bleeding risk in FXI deficiency and should be studied further in larger prospective clinical studies.

To cite this article: Que  lin F, Trossae È rt M, Sigaud M, Mazancourt PDE, Fressinaud E. Molecular basis of severe factor XI de®ciency in seven families from the west of France. Seven novel mutations, including an ancient Q88X mutation. J Thromb Haemost 2004; 2: 71±6.Summary. Inherited factor (F)XI de®ciency is a rare disorder in the general population, though it is commonly found in individuals of Ashkenazi Jewish ancestry. In particular, two mutationsÐa stop mutation (type II) and a missense mutation (type III)Ðwhich are responsible for FXI de®ciency, predominate. The bleeding tendency associated with plasma FXI de®-ciency in patients is variable, with $50% of patients exhibiting excessive post-traumatic or postsurgical bleeding. In this study, we identi®ed the molecular basis of FXI de®ciency in 10 patients belonging to six unrelated families of the Nantes area in France and one family of Lebanese origin. As in Ashkenazi Jewish or in French Basque patients, we have identi®ed a new ancient mutation in exon 4 resulting in Q88X, speci®c to patients from Nantes, that can result in a severely truncated polypeptide. Homozygous Q88X was found in a severely affected patient with an inhibitor to FXI and in three other unrelated families, either as homozygous, heterozygous or compound heterozygous states. Other identi®ed mutations are two nonsense mutations in the FXI gene, in exon 7 and 15, resulting in R210X and C581X, respectively, which were identi®ed in three families. A novel insertion in exon 3 (nucleotide 137 G), which causes a stop codon, was characterized. Finally, sequence analysis of all 15 exons of the FXI gene revealed three missense mutations resulting in G336R and G350A (exon 10) and T575M (exon 15). Two mutations (T575M and G350A) with discrepant antigen and functional values are particularly interesting because most of the described mutations are associated with the absence of secreted protein.

To cite this article: Dib N, Quelin F, Ternisien C, Hanss M, Michalak S, de Mazancourt P, Rousselet MC, Calè s P. Fibrinogen angers with a new deletion Summary. Introduction: This study reports a family with chronically abnormal blood liver function tests (LFT) and congenital hypofibrinogenemia. The proposita had cirrhosis initially related to alcohol abuse and chronic viral hepatitis C (HCV), but abnormal LFT persisted even when alcohol intake was stopped and despite HCV treatment was efficient based on serum RNA negative testing. Results: Needle biopsy specimens of the proposita and her brother showed eosinophilic intracytoplasmic inclusions that reacted strongly with fibrinogen antisera on direct immunofluorescence. Electron microscopic examination showed that the rough endoplasmic reticulum was filled with inclusions that consisted of densely packed, curved tubular structures arranged in a fingerprint-like pattern. Coagulation studies revealed low functional and antigenic fibrinogen concentrations suggestive of hypofibrinogenemia. Amplification and DNA sequencing showed a heterozygous deletion of the a7690 to g7704 nucleotides of the c chain gene in the 3¢end of exon 8 (g 7690_7704del14; Genbank access M10014); this deletion encompassed the splicing site at position 7703 and predicts in a new putative consensus splicing sequence (AATGgtatgtt). RNA was extracted from a liver specimen from the propositaÕs brother. The cDNA obtained by reverse transcription polymerase chain reaction confirmed the usage of a newly generated donor site at position 7688 of the genomic sequence resulting in an in-frame heterozygous 5 amino acid deletion p.G372_Q376del) and that this mutation is responsible for a new splicing site at position 7688 of the genomic sequence. Conclusion: we suggest that the molecular defect in fibrinogen Angers results in an impaired assembly and causes defective secretion and hepatic storage of fibrinogen.

Factor XI (FXI) deficiency is an inherited autosomal recessive disorder associated with bleeding of variable severity. However, many cases of dominant disease transmission have been recently described. This disorder is rare in the general population, whereas it is commonly found in individuals of Ashkenazi Jewish ancestry. This study reports the molecular genetic analysis of FXI deficiencies in 11 unrelated families of different origin. Five novel mutations have been identified. Severe FXI deficiency of two unrelated patients resulted from two novel mutations: one deletion (960-961delGT) in exon 9 predicting a frameshift, and a Ser-4Leu mutation located in the signal peptide. In addition, three novel missense mutations associated with partial FXI deficiency have been identified: Cys122Tyr, Glu297Lys and Glu579Lys.

ABSTRACTwith the PCR primers using the dye terminator sequencing kit from Applera Courtaboeuf, France. Informed consent was obtained from all patients. This work was approved by the local ethics committees (approvals DC 2008-214 and DC 2008-880).