Rare congenital coagulation factor defects in Finland

Phenotypic consequences of genetic variation at hemizygous alleles: Sotos syndrome is a contiguous gene syndrome incorporating coagulation factor twelve (FXII) deficiency

PURPOSE

We tested the hypothesis that Sotos syndrome (SoS) due to the common deletion is a contiguous gene syndrome incorporating plasma coagulation factor twelve (FXII) deficiency. The relationship between FXII activity and the genotype at a functional polymorphism of the FXII gene was investigated.

METHODS

A total of 21 patients including those with the common deletion, smaller deletions, and point mutations, and four control individuals were analyzed. We examined FXII activity in patients and controls, and analyzed their FXII 46C/T genotype using direct DNA sequencing.

RESULTS

Among 10 common deletion patients, seven patients had lower FXII activity with the 46T allele of the FXII gene, whereas three patients had normal FXII activity with the 46C allele. Two patients with smaller deletions, whose FXII gene is not deleted had low FXII activity, but one patient with a smaller deletion had normal FXII. Four point mutation patients and controls all had FXII activities within the normal range.

CONCLUSION

FXII activity in SoS patients with the common deletion is predominantly determined by the functional polymorphism of the remaining hemizygous FXII allele. Thus, Sotos syndrome is a contiguous gene syndrome incorporating coagulation factor twelve (FXII) deficiency.

Subdural hematoma in a patient with Hageman trait--case report

A 61-year-old man with severe factor XII deficiency presented with a subdural hematoma appearing as mixed but mainly high density by computed tomography in the left frontotemporoparietal region. No cranial injury was reported in the medical history of the patient. Clotting system study showed less than 1% functional activity of factor XII, whereas the levels of the other clotting factors were within the normal ranges. Partially clotted and hemolyzed subdural hematoma was removed through a craniotomy. The postoperative course was uneventful. The patient later died of severe circulatory-respiratory failure. We believe that the subdural hematoma may have developed as a result of a minor head trauma sustained in the past. We suggest that impairment of fibrinolytic activation related to severe factor XII deficiency might have contributed to the delay of dissolution of the subdural hematoma which, under ordinary circumstances, would have formed chronic subdural hematoma.

John Hageman's factor and deep-vein thrombosis: Leiden thrombophilia Study

Because the relationship between factor XII deficiency and venous thrombosis is unclear and study results seem contradictory, we undertook a population-based case-control study. Among 350 unselected patients younger than 70 years, with a first, objectively confirmed, episode of deep-vein thrombosis and without underlying malignant disease we detected a 6% frequency (21/350 patients) of factor XII deficiency (activity level < 57%). Among 350 healthy control subjects, matched for age and sex, the frequency was 5% (18 subjects). Thus there is no increase in prevalence of factor XII deficiency among thrombosis patients and no increase in thrombosis risk for subjects with low factor XII levels (matched odds ratio 1.2 (95% CI 0.6-2.4)). In addition, there was no relation between strata of factor XII levels and thrombosis risk. In conclusion, we do not consider factor XII to be a determinant of deep-vein thrombosis.

Preparation and properties of a therapeutic factor IX concentrate

A method for the large-scale preparation of a coagulation factor IX concentrate from human plasma is described. The method includes absorption of the coagulation factors from cryosupernatant plasma to DEAE-Sephadex, extensive washing of the gel and elution of the coagulation factors with 0.5 M phosphate buffer at 6.85, followed by desalting of the eluate in a column of Sephadex G-25, then by lyophilization, dissolving and sterile filtration, and finally by freeze-drying of the final product. Experiments performed with HBsAg-positive plasma demonstrated a decrease in the HBsAg content by a factor of 10(-5) during the process. The product is inactive in a Na-PTT assay. The process yields an about 100-fold purified factor IX concentrate containing also factors II, VII, and X, but in relatively smaller amounts. The average yield relative to factor IX is 60%. The batch size has been from 16 to 150 litres of plasma and about 300 batches of the concentrate have been prepared. About 5,100 bottle (about 4.0 X 10(6) U of factor IX) of the concentrate have been used in the treatment of patients with haemophilia B. The clinical effect has always been good and the in vivo response to factor IX was 1.15 +/- 0.30%/U/kg body weight. Two cases of HBsAg-negative hepatitis that may have been caused by the concentrate, were detected. No thrombotic complications were found.