Molecular characterization of five Italian families with inherited severe factor XIII deficiency.

Factor XIII (FXIII) deficiency is a very rare (1:2 000 000) severe autosomal recessive bleeding disorder, mostly due to mutations in the coagulation FXIII A-subunit gene. We have studied the molecular basis of FXIII deficiency in five unrelated Italian families. The coding region, intron-exon boundaries and 5'- and 3'-untranslated regions of the FXIII gene encoding the A subunit were amplified and directly sequenced. Candidate mutations were identified in all the patients. Three novel mutations occurred in three patients. These include a novel homozygous deletion of two base pairs (bp) in exon 14 (c.2002-2003 DelCT). This deletion causes a frameshift from Leu667 and the formation of a stop codon at amino acid position 681. The second patient presents a novel homozygous (c.2126 G>A) transition in exon 15, predicting a Ser708Asn in Barrel 2 domain. The third patient is compound heterozygote for two missense mutations, a previously reported Arg260His substitution, and a novel transition in exon 4 (c.560 C>T) predicting a Pro186Leu in the core domain. The remaining two patients have two previously reported mutations: a 4-bp homozygous deletion in exon 11 (c.1392-1395 Del AATT), previously reported to occur in the Vicenza Area, and a homozygous nonsense mutation in exon 8 (c.979 C>T) predicting an Arg326X in the core domain. The novel mutations occurred at amino acid residues highly conserved among different species (pig, monkey, mouse and dog) and were not detected in 110 normal alleles. Structural analysis shows that Pro186Leu mutation leads to the replacement of the rigid proline pyrrolidine ring by the larger and more flexible leucine side chain and Ser708Asn may probably disrupt the hydrogen bond with Ala291.

Prothrombin complex concentrates for urgent anticoagulation reversal in patients with intracranial haemorrhage.

BACKGROUND: Intracranial haemorrhage (ICH) is a serious and potentially fatal complication of oral anticoagulant therapy (OAT). Prothrombin complex concentrates (PCCs) produce a rapid and effective reversal of OAT effects, but little evidence exists on their efficacy and safety in the management of ICH in patients on OAT. AIM: To evaluate the efficacy and safety of PCCs for the rapid reversal of OAT in patients with ICH. METHODS: Patients suffering from acute ICH while receiving OAT were eligible for this prospective cohort study if their international normalized ratio (INR) was > or = 2.0. Stratified 35-50 IU kg(-1) PCC doses were infused based on initial INR. RESULTS: A total of 92 patients (50 males; mean age 74 years, range 34-92 years) were included. The median INR at presentation was 3.3 (range 2-9). At 30 min after PCC administration the median INR was 1.4 (range 0.9-3.1), declining to < or = 1.5 in 75% of patients. The benefit of PCC was maintained for a long time, since in 98% of all post-infusion time points through 96 h the median INR remained < or = 1.5 (median 1.19; range 0.9-2.3). During hospitalization neither thrombotic complications nor significant adverse events were observed and 11 patients died (11.9%). None of the deaths was judged to be related to PCC administration. CONCLUSIONS: PCC administration is an effective, rapid and safe treatment for the urgent reversal of OAT in patients with ICH. Broader use of PCC in this clinical setting appears to be appropriate.