Complications following implant removal in patients with proximal femur fractures - an observational study over 16 years.

BACKGROUND: Fractures of the proximal femur commonly occur but the majority of orthopaedic surgeons do not consider general hardware removal as a routine necessity. Indications and time interval for hardware removal in this special selected patient group is still controversial. Therefore we performed a retrospective study to address the following questions: 1) Is there a difference between the medically- (infection, mechanical problems, implant failure) and non-medically indicated group (patients demand, meteoro-sensitivity, foreign body sensation) in relation to complications? 2) Is there a correlation regarding time interval between implantation and removal comparing these two groups? 3) Is there a context related refracture rate? 4) Should non-medically indicated implant removal (IR) be performed due to persistent pressure from the patient? HYPOTHESIS: We hypothesized that non-medically indicated implant removals should be avoided due to a significantly higher number of associated complications. PATIENTS AND METHODS: A total of 371 consecutive patients with 424 hardware removal procedures following a proximal femur fracture, between 08/1992 and 11/2008, have been included. Study population was divided into two groups according to their indication for implant removal: medically indicated group (MIR) consisted of 299 patients (80.59%) and 72 patients (19.41%) were assigned to the non-medically indicated (NMIR) group. RESULTS: In the NMIR subgroup a total of (n = 21) 28% complications occurred compared to 11.46% in the MIR subgroup; (P < 0.005), 86.51% of IR in the MIR group were performed within 1.5 years, compared to 79.17% in the NMIR group after 2 to 3.5 years (NS). In the MIR group 1 refracture occurred, compared to 4 in the NMIR group (NS). CONCLUSION: Non-medically indicated implant removal should be avoided due to the higher complication rate of 28%. Surgeons and patients should be aware of the imminent complications and therefore implant removal should only be performed for good medical reasons. LEVEL OF EVIDENCE: Level IV. Historical case study.

Prevalence of iron deficiency across different tumors and its association with poor performance status, disease status and anemia.

BACKGROUND: Only limited data on the prevalence of iron deficiency (ID) and its correlation with clinical parameters are available in cancer. ID frequently contributes to the pathogenesis of anemia in patients with cancer and may lead to several symptoms such as impaired physical function, weakness and fatigue. PATIENTS AND METHODS: Parameters of iron status and clinical parameters were evaluated in 1528 patients with cancer who presented consecutively within a four-month period at our center. One thousand fifty-three patients had solid tumors and 475 hematological malignancies. RESULTS: ID [transferrin saturation (TSAT) < 20%] was noted in 645 (42.6%) of the 1513 patients with TSAT tests available and 500 (33.0%) were anemic. ID rates were highest in pancreatic (63.2%), colorectal (51.9%) and lung cancers (50.7%). Of the 409 iron-deficient patients in whom serum ferritin levels were available additionally to TSAT, 335 (81.9%) presented with functional ID (FID) (TSAT < 20%, serum ferritin ≥30 ng/ml) and 74 (18.1%) with absolute ID. In patients with solid tumors, prevalence of ID correlated with cancer stage at diagnosis (P = 0.001), disease status (P = 0.001) and ECOG performance status (P = 0.005). CONCLUSIONS: ID was frequently noted in cancer and was associated with advanced disease, close proximity to cancer therapy, and poor performance status in patients with solid tumors.

Evaluation of the PC-1 K121Q and G2906C variants as independent risk factors for ischaemic stroke.

UNLABELLED: Overexpression of plasma cell membrane glycoprotein-1 (PC-1) inhibits insulin receptor tyrosine kinase activity and thus favours insulin resistance and atherosclerotic vascular disease. Recent findings indicate that the minor variant K121Q in the PC-1 gene confers an increased risk for early myocardial infarction independent of other established risk factors. We hypothesized that genetic variants in PC-1 may also influence the risk for cerebrovascular disease. AIM: Therefore, we assessed the association of the PC-1 K121Q variant in the coding region and a polymorphism (G2906C) in the 3' untranslated region of the PC-1 gene with the risk of stroke. PATIENTS: We analyzed 1014 patients with a history of ischaemic stroke from the Vienna stroke registry and 1001 control individuals without vascular disease. RESULTS, CONCLUSION: Genotype frequencies of both genetic variants were similar in patients and controls in the total study population. By multivariate analysis, no interactions were observed between the PC-1 genotype and established vascular risk factors. However, the PC-1 2906C allele was significantly more frequent in patients who suffered from stroke before the age of 40 years. In these patients the risk for ischaemic stroke was increased four-fold.

Sex differences in the association between albumin and all-cause and vascular mortality.

BACKGROUND: Low serum albumin levels are associated with cardiovascular disease and mortality risk. This study evaluated the predictive value of low serum albumin for all-cause-mortality in a large Viennese patient cohort and investigated sex differences in the association between serum albumin and mortality. MATERIALS AND METHODS: Serum albumin concentrations of 285 930 patients, who attended the General Hospital Vienna between 1992 and 2002, were evaluated and linked with the Austrian Death Registry. The median observation period was 7.4 +/- 4.0 years and the death rate was 16.8%. For Cox regression analysis, albumin levels were divided into deciles, the highest category served as reference value. To analyse associations between albumin and mortality independent of liver function, results were adjusted for cholinesterase, which indicates protein synthesis capacity of the liver. RESULTS: Hazard ratios for all-cause-mortality increased linearly with decreasing albumin levels from 1.05 in the 9th to 2.98 in the 1st decile. Adjusted for cholinesterase, the relative risk for mortality was still 1.91 in the lowest category. Compared with women, men had an average 50% increased risk of death in almost every decile, adjusting for cholinesterase reduced the sex difference to a 10-20% higher mortality risk for men. In critically ill patients, hazard ratios for all-cause-mortality ranged from 4.5 in the 9th decile to 9.5 in the lowest albumin category. CONCLUSION: This study demonstrates a strong inverse association between serum albumin and mortality in a large patient cohort. The predictive value of low albumin was remarkably higher in men than in women.

Elevated tryptase levels selectively cluster in myeloid neoplasms: a novel diagnostic approach and screen marker in clinical haematology.

BACKGROUND: Recent data suggest that tryptase, a mast cell enzyme, is expressed in neoplastic cells in myeloid leukaemias. In several of these patients, increased serum tryptase levels are detectable. MATERIALS AND METHODS: We have determined serum tryptase levels in 914 patients with haematological malignancies, including myeloproliferative disorders (n = 156), myelodysplastic syndromes (MDS, n = 241), acute myeloid leukaemia (AML, n = 317), systemic mastocytosis (SM, n = 81), non-Hodgkin's lymphoma (n = 59) and acute lymphoblastic leukaemia (n = 26). Moreover, tryptase was measured in 136 patients with non-neoplastic haematological disorders, 102 with non-haematological disorders and 164 healthy subjects. RESULTS: In healthy subjects, the median serum tryptase was 5.2 ng mL(-1). Elevated serum tryptase levels were found to cluster in myeloid neoplasm, whereas almost all patients with lymphoid neoplasms exhibited normal tryptase. Among myeloid neoplasms, elevated tryptase levels (> 15 ng mL(-1)) were recorded in > 90% of patients with SM, 38% with AML, 34% with CML and 25% with MDS. The highest tryptase levels, often > 1000 ng mL(-1), were found in advanced SM and core-binding-factor leukaemias. In most patients with non-neoplastic haematological disorders and non-haematological disorders analysed in our study, tryptase levels were normal, the exception being a few patients with end-stage kidney disease and helminth infections, in whom a slightly elevated tryptase was found. CONCLUSIONS: In summary, tryptase is a new diagnostic marker of myeloid neoplasms and a useful test in clinical haematology.

Classification of chronic kidney disease by estimated glomerular filtration rate.

BACKGROUND: Serum creatinine concentration alone as a marker of kidney function is inadequate. Thus several equations for estimating glomerular filtration rate (eGFR) have been proposed within the last years. PATIENTS AND METHODS: In our study we compared three frequently used equations, the abbreviated modification of diet in renal disease (MDRD) formula, the extended MDRD formula and the recently proposed Mayo clinic equation in a large patient cohort. RESULTS: A total of 244 507 patients attending the Vienna General Hospital were evaluated for their kidney function and three equations for eGFR were compared. The median age of the patients was 51 years (ranging from 18.0 to 102.6 years) with 44.3% males (n = 108 527). We observed a significant increase of patients with eGFR classes four and five (according to Kidney Disease Outcomes Quality Initiative (K/DOQI) guidelines) with advanced age. Whereas approximately 1% of patients < 30 years presented with eGFR classes four and five (defined as eGFR < 30 mL min(-1) 1.73 m(-2)), this prevalence increased up to approximately 12% in patients at the age of 80 years or older. All three equations showed comparable results for eGFR classes four and five. The proportion of patients with mild to moderate impairment of kidney function is higher using both MDRD equations. CONCLUSIONS: The MDRD equations (particularly the abbreviated MDRD formula) result in considerably higher rates of eGFR classes two and three compared to the Mayo Clinic equation, while all three were comparable in classes four and five. This should be considered when eGFR is used in the diagnosis of chronic kidney disease.

Coagulation factor XII (FXII) activity, activated FXII, distribution of FXII C46T gene polymorphism and coronary risk.

BACKGROUND: Whether factor XII (FXII) activity, its 46C>T polymorphism and activated FXII (FXIIa) are associated with coronary heart disease (CHD) remains to be determined. METHODS: FXII, FXIIa and the FXII 46C>T polymorphism were determined in a hospital-based cohort of 2615 patients undergoing coronary angiography. RESULTS: Fifty-seven per cent of the participants were identified as wild-type (46CC), 38% as heterozygous (46CT) and 5% as homozygous (46TT) for FXII 46C>T. FXII and FXIIa levels were significantly lower in carriers of the T-allele: 132 (97-151) U dL(-1) FXII in 46CC, 87 (77-99) U dL(-1) FXII in 46CT and 53 (42-67) U dL(-1) FXII in 46TT carriers (P < 0.001), and 2.8 (2.3-3.5) microg L(-1) FXIIa in CC, 2.1 (1.6-2.6) microg L(-1) FXIIa in CT and 1.2 (0.9-1.5) microg L(-1) FXIIa in TT carriers (P < 0.001; medians, lower and upper quartiles). Patients with stable CHD (n = 935), a history of myocardial infarction (n = 785) or who were suffering from acute coronary syndromes (ACS; n = 323) had significantly lower FXII levels than controls (n = 572). The differences remained statistically significant after adjustments for age, sex, diabetes mellitus, smoking, hypercholesterolemia and hypertension. Significantly reduced FXIIa levels in ACS patients lost significance once adjusted for covariates. FXII genotype was not associated with any clinical phenotype. CONCLUSION: Lower FXII activity represents an independent risk for CHD and ACS. This is not the case for FXIIa levels or the FXII 46C>T variation.

Polymorphisms in the coagulation factor VII gene and risk of primary intracerebral hemorrhage.

Data concerning genetic factors that may influence the risk of primary intracerebral hemorrhage (PICH) are scarce. One previous study, indicated that the carriers of the (-323)Ins allele of the coagulation factor VII (FVII) have an increased risk of PICH. Another recent study, tested the effect of apolipoprotein E. We analyzed, whether the (-401)G --> T polymorphism, which is in linkage disequilibrium (LD) with the 10-bp Ins/Del polymorphism at position (-323), or the (-402)G --> A polymorphisms of the FVII gene are associated with an increased risk for PICH. We performed a small case-control study in 85 patients with PICH and in 85 healthy control subjects. To each patient a control was individually matched for age, gender, and hypertension. We did not find any significant differences in allele frequencies for the A allele of the FVII (-402)G --> A polymorphism (0.25 vs. 0.25; P = 0.900, OR = 1, ns.) nor for the T Allele of the FVII (-401)G --> T polymorphism (0.09 vs. 0.12; P = 0.480, OR = 1.38, ns.). The analysis of haplotype distributions did not reveal significant differences. Our results do not support the hypothesis that the investigated polymorphisms in the FVII gene are significantly associated with the risk for PICH.

4G4G genotype of the plasminogen activator inhibitor-1 promoter polymorphism associates with disseminated intravascular coagulation in children with systemic meningococcemia.

BACKGROUND: Meningococcal disease may present as sepsis, meningitis or a combination of both. Impaired fibrinolysis and massive elevation of the plasminogen activator inhibitor-1 (PAI-1) is a characteristic feature of meningococcal sepsis. We and others have reported an association between mortality and the functional 4G/5G promoter polymorphism of the PAI-1 gene in children with meningococcal sepsis. OBJECTIVE: Multicenter study to investigate the association of the 4G/5G PAI-1 polymorphism and disseminated intravascular coagulation (DIC) in children with meningococcal disease in a Central European population. PATIENTS/METHODS: Blood samples and clinical information of 326 previously healthy children with meningococcal infection were collected from 95 pediatric hospitals in Germany, Switzerland, Italy, and Austria from 2000 to 2002. RESULTS: DIC, defined as platelet counts below 100 G L(-1), increased D-dimer levels and prolonged prothrombin time, was significantly associated with the 4G4G genotype [31 of 63 (49%) vs. 55 of 175 (31%), P = 0.014], resulting in a hazard ratio (HR) of 1.5 (95% confidence interval 1.1-2.1) to develop DIC. Carriers of the 4G4G genotype showed significantly lower platelet counts (183 G L(-1) vs. 227 G L(-1), P = 0.009) on admission. Fibrinogen and C-reactive protein levels were not associated with the PAI-1 4G/5G polymorphism, nor were white blood cell counts. CONCLUSIONS: Our data show a correlation between the 4G4G genotype of the PAI-1 gene and development of DIC in meningococcal infection.

Evidence of a U-shaped association between factor XII activity and overall survival.

INTRODUCTION: The clinical relevance of decreased coagulation factor XII (FXII) plasma activity as a risk factor for both venous and arterial thrombosis is still discussed controversially. The current study evaluated the predictive value of FXII levels for all-cause mortality in a large Viennese patient cohort. PATIENTS AND METHODS: Individuals, whose FXII activity levels were determined for suspected coagulation disorders or thrombophilia screening between 1991-2003 were included in this study (n = 8936, 51% male, 49% female, median age 43 years). Death/survival was determined by record linkage with the Austrian Death Registry. The median observation period was 5 years covering a total of 46 400 person years; the death rate was 17.1%. For Cox regression analysis, FXII plasma activity was divided into 11 categories of 10% steps with the category of > 100% FXII serving as a reference category. RESULTS: With decreasing FXII plasma activity, hazard ratios for all-cause mortality gradually increased linearly from 1.0 in the > 100% category to 1.5 (95% CI: 1.2-1.9) in the 80-90% category to 4.7 (95% CI: 3.4-6.5) in the 10-20% category. Similar results were obtained, when only vascular mortality or death as a result of ischemic heart disease was considered. No significant increase in all-cause mortality (HR: 1.4, 95%CI 0.7-2.8) was observed in the small group of FXII-deficient subjects [0-10% category (n = 58)]. CONCLUSIONS: This study first demonstrates a strong and almost linear association of FXII plasma activity between 90% and 10% with all-cause mortality in a large Viennese patient cohort. Interestingly, mortality rates are not increased when FXII activity is below 10%, resulting in a U-shaped survival curve.

Association of low-grade inflammation with nephropathy in type 2 diabetic patients: role of elevated CRP-levels and 2 different gene-polymorphisms of proinflammatory cytokines.

BACKGROUND: Chronic inflammatory processes are thought to play a key role in the development of micro- and macrovascular complications in type 2 diabetes mellitus. An association between low -grade inflammation and type 2 diabetes has been described in some studies. We assayed the association of two frequent polymorphisms in proinflammatory cytokines: the interleukin 6 G(-174)C promoter polymorphism [IL-6G(-174)C], the exon 2 interleukin receptor antagonist insertion deletion polymorphism [IL1RA]) and serum CRP levels with the prevalence of diabetic nephropathy in patients suffering from type 2 diabetes mellitus. SUBJECTS AND METHODS: A total of 141 patients with type 2 diabetes mellitus, with and without diabetic nephropathy was genotyped for the above mentioned polymorphisms: 66 with normoalbuminuria, 31 with microalbuminuria and 44 with macroalbuminuria. CRP levels were analysed by a high sensitivity - immunnephelometric assay. RESULTS: While a significant association be-tween macroalbuminuria and CRP could be observed (p<0,015), no associations were found between IL-6G(-174)C or IL1RA genotype and any stage of nephropathy. CRP-levels were similar in the 3 different IL-6G(-174)C genotypes as well as in the 2 IL1RA genotypes. CONCLUSIONS: In type 2 diabetic subjects elevated CRP levels are associated with an increased prevalence of albuminuria. The two investigated proinflammatory polymorphisms do not seem to contribute to initiation of nephropathy in type 2 diabetic patients but we cannot exclude effects of these polymorphisms on course of nephropathy.

Polymorphism in the tissue factor region is associated with basal but not endotoxin-induced tissue factor-mRNA levels in leukocytes.

OBJECTIVE: Tissue factor (TF) plays a central role during disseminated intravascular coagulation (DIC) in sepsis. We hypothesized that a frequent D/I polymorphism, at nucleotide position -1208 in the promoter region, could influence TF-mRNA and downstream coagulation. METHODS: Basal- and lipopolysaccharide (LPS)-induced TF-mRNA expression, microparticle-associated TF-procoagulant activity and coagulation were determined in healthy men (n = 74) before and after endotoxin (LPS) infusion (2 ng kg(-1)). Basal values of TF-mRNA ranged between 34 and > 37.5 cycles. RESULTS: Baseline TF-mRNA levels significantly differed between genotypes: I/I carriers had almost 2-fold higher TF-mRNA levels compared to D/D carriers at baseline (P < 0.01). In accordance, higher levels of microparticle-associated TF-procoagulant activity could be seen in I/I carriers. However, the genotype did not affect basal or LPS-induced levels of prothrombin fragment F1+2, D-dimer or cytokines including tumor necrosis factor and interleukin-6. CONCLUSION: The TF-1208 polymorphism is functional in that it regulates basal TF-mRNA in circulating monocytes and circulating microparticle-associated TF-procoagulant activity in vivo, but does not influence the relative increase in TF-mRNA or coagulation activation during low-grade endotoxemia.

Haem oxygenase-1 genotype and cardiovascular adverse events in patients with peripheral artery disease.

BACKGROUND: A functional GT dinucleotide length polymorphism in the haem oxygenase-1 (HO-1) gene promoter is thought to be involved in the pathogenesis of cardiovascular disease. Short (< 25) (GT)n repeats are suggested to facilitate enhanced HO-1 up-regulation in response to injury and confer potent anti-inflammatory and antioxidative effects. MATERIALS AND METHODS: We investigated the association between the HO-1 GT-polymorphism and cardiovascular outcome in 472 patients with advanced peripheral artery disease. Cardiovascular risk profile and DNA samples for determination of the HO-1 genotype (carrier vs. noncarrier of a short (GT)n repeat allele) were obtained at baseline, and patients were followed for median 21 months for the occurrence of coronary events (myocardial infarction, percutaneous coronary interventions and coronary artery bypass graft), cerebrovascular events (stroke or carotid revascularization) and all-cause mortality. RESULTS: Coronary events occurred in 48 patients (9%), cerebrovascular events in 40 patients (9%) and 59 patients (13%) died. In total, 173 major adverse cardiovascular events (MACE) occurred in 133 patients (28%). Carriers of the short (GT)n repeat allele had a 0.46-fold reduced adjusted hazard ratio for coronary events (P = 0.016) as compared to noncarriers. No significant difference was found for cerebrovascular events, mortality and overall MACE. CONCLUSION: Apparently, the HO-1 genotype exerts potentially protective effects against coronary adverse events in patients with peripheral artery disease. Homozygous and heterozygous carriers of < 25 (GT)n repeats had lower rates of myocardial infarction, percutaneous coronary interventions and coronary bypass operations compared to patients with longer (GT)n repeats.

Loss of normal circadian profile of urine excretion in idiopathic restless legs syndrome.

BACKGROUND: This study was performed to elucidate preliminary observations of excessive nighttime urine excretion in idiopathic restless legs syndrome (iRLS). METHODS: Seventeen patients, with normal serum creatinine, blood urea nitrogen, and urate, and 11 healthy controls were examined. We measured excretory renal function parameters (urine volume, osmolarity, sodium, chloride, potassium, calcium, phosphate, microalbumin, aldosterone, creatinine) between 7:00 am and 10:00 pm and between 10:00 pm and 7:00 am. RESULTS: During the nighttime, volume (P=0.006), sodium (P=0.009), and chloride excretion (P=0.001) were significantly higher, and osmolarity (P=0.025) was significantly lower in patients as compared to controls. In comparing daytime to nighttime, controls showed the physiological reduced nocturnal excretion of volume (P=0.009) and chloride (P=0.023), and an increased osmolarity (P=0.026), but patients showed similar excretion rates of these parameters (all differences ns). CONCLUSIONS: These data indicate a loss of normal circadian profile of urine excretion in iRLS. The elevated nighttime excretion, with values similar to those in the daytime, hint at a possibly elevated fluid, sodium, and chloride intake during daytime.

Is elevated mean platelet volume associated with a worse outcome in patients with acute ischemic cerebrovascular events?

BACKGROUND AND PURPOSE: Increased mean platelet volume (MPV), indicating higher platelet reactivity, is associated with an increased risk of myocardial infarction. Higher levels of MPV have been found in patients with acute ischemic stroke than in control subjects. Data from smaller studies regarding an association between MPV and stroke severity and outcome have been controversial. If such an association exists, MPV might help to identify patients at increased risk of a severe course of acute cerebrovascular disease. METHODS: Within a multicenter, cross-sectional study nested in a cohort, we analyzed the relation between MPV and stroke severity as determined by the modified Rankin Scale after 1 week in 776 patients with acute ischemic stroke or transient ischemic attack. By multivariate logistic regression modeling, we determined the influence of MPV on stroke severity, adjusting for potential confounding factors. RESULTS: Patients within the highest quintile of MPV had a significantly higher risk of suffering a severe stroke, defined as modified Rankin Scale score of 3 to 6, compared with patients within the lowest quintile (odds ratio=2.6; 95% confidence interval, 1.6 to 4.1; P<0.001). This association remained significant after adjustment for possible confounding factors (odds ratio=2.2; 95% confidence interval, 1.2 to 4.0; P=0.013). CONCLUSIONS: Our results indicate that an elevated MPV is associated with a worse outcome for acute ischemic cerebrovascular events independent of other clinical parameters.

A polymorphism of the interleukin-6 gene promoter and idiopathic recurrent miscarriage.

BACKGROUND: Cytokines have been described to play a major role in the pathogenesis of idiopathic recurrent miscarriage (IRM). We investigated the association between IRM and a polymorphism of the interleukin-6 (IL-6) gene and IL-6 serum levels. METHODS: In a prospective case-control study, we studied 161 women with IRM and 124 healthy controls. Peripheral venous puncture, DNA extraction and PCR were employed to genotype women for the presence of a polymorphism at position -174 in the promoter region of IL-6. Serum IL-6 levels were assessed by a commercially available ELISA. RESULTS: Allele frequencies among women with IRM and controls were 63.4 and 58.1% respectively for allele G (wild type), and 36.6 and 41.9% respectively for allele C (mutant). No association between allele C and the occurrence of IRM was found (odds ratio 0.8; 95% confidence interval = 0.57-1.12; P = NS). IL-6 serum levels were not significantly different between genotypes and between the study and control groups. CONCLUSIONS: This is the first report on an IL-6 polymorphism in IRM. Although known to alter IL-6 expression, the IL-6 polymorphism investigated was not associated with IRM and alterations in IL-6 serum levels in a Middle-European Caucasian population.

A common C-->T polymorphism at nt 46 in the promoter region of coagulation factor XII is associated with decreased factor XII activity.

Coagulation factor XII (FXII) deficiency is rarely found to be associated with bleeding, but single reports demonstrated thromboembolic events in FXII-deficient patients. Currently, the biological role of FXII is still discussed controversially. It is well known that plasma levels of FXII show great interindividual variability. Recently, it has been demonstrated that a frequently occurring C-->T polymorphism in the FXII promoter region at nucleotide (nt) 46 is associated with lower plasma FXII activity levels in Orientals. In our study, we evaluated the frequency of this polymorphism in a randomly selected sample of newborns and investigated whether this C-->T polymorphism also contributes to the frequently observed moderate FXII deficiency in Europeans. We developed a new mutagenically separated polymerase chain reaction assay (MS PCR), which allows mutation detection without the use of restriction enzymes. Among 100 healthy newborns, we found 64% homozygous carriers of the wildtype FXII 46C allele, 29% were heterozygous for FXII C46T, and 7% homozygous for FXII 46T. Evaluation of plasma FXII activity and genotype in 80 randomly selected and unrelated individuals revealed a highly statistically significant (P<.001) association of the FXII 46T allele with reduced FXII plasma activity. Individuals carrying the homozygous FXII 46C genotype had a mean of 1.17 U/ml (+/-0.31 U/ml), individuals heterozygous for FXII C46T showed a mean of 0.70 U/ml (+/-0.31 U/ml), and subjects homozygous for FXII 46T had only 0.44 U/ml (+/-0.10 U/ml) plasma FXII activity.