Association of the protein Z ATG haplotype with symptomatic nonvascular stroke or thromboembolism in white children: a family-based cohort study

Linkage Analysis of the Chromosome 5q31-33 Region Identifies JAKMIP2 as a Risk Factor for Graves' Disease in the Chinese Han Population

Background

This study aimed to investigate susceptibility to Graves’s disease and the association with the 5q32–33.1 region on chromosome 5 in a Chinese Han population.

Material/Methods

Eighty Chinese Han multiplex families included first-degree and second-degree relatives with Graves’ disease. Eight microsatellite markers on chromosome 5 at the 5q32–33.1 region underwent linkage analysis and the association between the regions D5S1480–D5S2014 were studied.

Results

The maximal heterogeneity logarithm of the odds (HLOD) score of D5S2090 was 4.29 (α=0.42) and of D5S2014 was 4.01 (α=0.34). A nonparametric linkage (NPL) score of 3.14 (P<0.001) was found for D5S2014. The D5S1480–D5S2014 region on chromosome 5 was associated with Graves’ disease, with eight haplotype domains. There were significant differences in the sixth and eighth haplotype domains between patients with Graves’ disease compared with normal individuals. Tagging single nucleotide polymorphisms (SNPs) of the sixth and eighth haplotype domains showed that individuals with SNP62 (rs12653715 G/C) who were GG homozygous had a significantly increased risk of Graves’ disease compared GC heterozygous or CC homozygous individuals. The transmission disequilibrium test (TDT) indicated that SNP62 (rs12653715) and SNP63 (rs12653081) loci in the Janus kinase and microtubule interacting protein 2 (JAKMIP2) gene showed dominant transmission from heterozygous parents to the affected offspring, and SNPs in the secretoglobin family 3A member 2 (SCGB3A2) gene showed no transmission disequilibrium. The haplotype JAKMIP2-1 was identified as being particularly significant.

Conclusions

JAKMIP2 gene polymorphism require further study as potential risk factors for Graves’ disease in the Chinese Han population.

The protein Z/protein Z-dependent protease inhibitor complex

Protein Z (PZ) is a vitamin K-dependent factor identified in human plasma in 1984 but it has no enzymatic activity. It is a cofactor of a serpin, the protein Z-dependent protease inhibitor (ZPI), and the complex PZ/ZPI inhibits activated factor X on phospholipid surfaces. In mice, the disruption of PZ or ZPI gene is asymptomatic, but enhances the thrombotic phenotype and mortality of other thrombotic risk factors. Most of the clinical studies focused on PZ. Despite conflicting results, a recent meta-analysis indicated that PZ deficiency could be a risk for venous and arterial thrombosis and early fetal loss. However, these conclusions are drawn from case-control studies of small size, constituting an important limitation. Recently, it was shown that PZ and/or ZPI are synthesised by normal kidney and different cancer cells, suggesting that the complex PZ/ZPI could play a role in inhibiting the tissue deposition of fibrin. The physiopathological consequences of these observations remain to be established. At this time, the measurement of plasma PZ and ZPI or analysis of their gene polymorphisms should not be performed routinely for the exploration of thrombophilia.

Developmental hemostasis: A lifespan from neonates and pregnancy to the young and elderly adult in a European white population

Absolute values of reference ranges for coagulation assays in humans vary within the entire lifespan and confirm the concept of developmental hemostasis. It is known that physiologic concentrations of coagulation factors (F) gradually increase over age: they are lower in premature infants as compared to full-term babies, healthy children or adults. Here we demonstrate in a cohort of 1011 blood donors and in a group of 193 healthy pregnant women, that the process of developmental hemostasis proceeds in adults. During the course of pregnancy F and activation markers steadily increase until delivery with a parallel decrease noticed for protein S. From adolescents, young adults to the elderly there is a further increase of F, reaching significance starting between 35 and 50years of age compared to younger subjects. Covering the entire lifespan FVIII and von-Willebrand-factor showed the lowest values in carriers of blood group "O". Apart from pregnancy differences related to gender, pill users, smoking habits or the presence of thrombophilic variants were reported. Laboratory test results should be compared to age-related reference intervals when hemostatic defects are suspected to avoid misclassifications as being "healthy", prone to "bleeding" or vice versa to "thrombosis".

Circulating protein Z concentration, PROZ variants, and unexplained cerebral infarction in young and middle-aged adults

Protein Z (PZ) is a vitamin K-dependent plasma protein that exhibits both pro- and anticoagulant properties. Both low and high PZ levels have been linked to ischaemic stroke. Although PZ-lowering gene variants have been found to be less common in ischaemic stroke, the relationship remains unclear. We investigated PZ levels and PROZ variants in a multi-ethnic case-control study of unexplained stroke in participants aged 18 to 64. Plasma PZ was measured in cases (≥2 months post-stroke) and controls. PZ polymorphisms G79A (rs3024735) and A13G (2273971) were genotyped. A combined genetic score (0-4 minor alleles) was created assuming additive effects. A total of 715 individuals (1:1.4 cases:controls) was included. Analyses revealed evidence of a non-linear association. After adjusting for demographic and clinical covariates, PZ levels >2.5 µg/ml (90^th %ile) were significantly associated with cryptogenic stroke (OR 2.41 [95 % CI 1.34, 4.34]) as compared with lower levels. Higher genetic score was related to progressively lower levels of PZ, and the presence of four minor alleles was associated with lower odds of stroke (adjusted OR 0.26 [95 % CI 0.07, 0.96]) versus 0 minor alleles. In this multi-ethnic study of young and middle-aged adults, there was evidence of a non-linear positive association between PZ level and unexplained stroke, with a directionally consistent association for genetic variants related to PZ levels and cryptogenic stroke. These findings support elevated PZ levels as a risk factor for cryptogenic stroke.

Contribution of protein Z gene single-nucleotide polymorphism to systemic lupus erythematosus in Egyptian patients

Protein Z has been reported to exert an important role in inhibiting coagulation. Polymorphisms in the protein Z gene (PROZ) may affect protein Z levels and thus play a role in thrombosis. This study aimed to investigate the prevalence and clinical significance of protein Z gene G79A polymorphism in Egyptian patients with systemic lupus erythematosus (SLE). We studied the distribution of the protein Z gene (rs17882561) (G79A) single-nucleotide polymorphism by PCR-restriction fragment length polymorphism in 100 Egyptian patients with SLE and 100 age, sex, and ethnically matched controls. There was no statistically significant difference in the distribution of the genotypes between SLE patients and the control group in our study (P = 0.103). But a statistically significant difference in the frequency of the alleles between SLE patients and controls was observed (P = 0.024). Also a significant association was detected between protein Z genotypes (and also A allele) and thrombosis, which is one of the manifestations of SLE (P = 0.004 and P = 0.001, respectively). Moreover, we observed a significant association between the protein Z AA and GA genotypes (and also A allele) and the presence of anticardiolipin antibodies (P = 0.016 and P = 0.004, respectively). The minor A allele of the G79A polymorphism in the protein Z gene might contribute to the genetic susceptibility of SLE in Egyptian patients. Also, an influence for this polymorphism on some of the disease manifestations has been elucidated, so protein Z G79A AG/AA may be a risk factor for thrombosis.

Protein Z, an anticoagulant protein with expanding role in reproductive biology

Protein Z (PZ) is a vitamin K-dependent factor characterized by its homology to other vitamin K-dependent factors (factors VII, IX, and X, protein C and protein S), but lacks any enzymatic activity. Instead, PZ acts as a cofactor for the inhibition of factor Xa through the serpin PZ-dependent protease inhibitor (ZPI). PZ deficiency is associated with a procoagulant state, highlighted by excessive FXa secretion and thrombin production, and is linked with several thrombotic disorders, including arterial vascular and venous thromboembolic diseases. A role for the PZ-ZPI complex in the regulation of physiological pregnancy has been demonstrated, highlighted by the progressive elevation in PZ levels in the first trimester of gestation, which then steadily decline toward delivery. An association between altered plasma PZ concentrations and adverse pregnancy outcomes (recurrent miscarriage, stillbirth, preeclampsia, intrauterine growth restriction, and placental abruption) has been reported. The mechanism by which PZ deficiency leads to adverse pregnancy outcomes is not clear, but it is multifactorial. It may be attributed to the anti-PZ IgG and IgM autoantibodies, which apparently act independently of classical antiphospholipid antibodies (lupus anticoagulant, anticardiolipin, and anti-β2-glycoprotein I antibodies). PZ deficiency has also been reported to be constitutional, and a number of variants in the PROZ (PZ) gene and SERPINA10 (ZPI) gene are linked with specific adverse pregnancy complications. This review summarizes the relationship between adverse pregnancy outcomes and acquired and constitutional PZ-ZPI deficiency, in order to understand whether or not PZ deficiency could be considered as a risk factor for poor pregnancy outcomes.

Protein Z variants associated with protein Z plasma levels and with risk of idiopathic recurrent miscarriage

Protein Z (PZ) deficiency due to anti-PZ autoantibodies and/or mutations in PZgene was linked with adverse pregnancy outcomes, including idiopathic recurrent miscarriage (IRM). We investigated the association of rs3024718, rs3024719, rs3024731, rs3024778, rs3024772, and rs3024735 (G79A) PZ variants and changes in PZ levels in 287 women with IRM, and 308 control women. Of the 6 single nucleotide polymorphisms (SNPs) analyzed, higher minor allele frequency of rs3024735 (G79A) and rs3024731 were seen in IRM cases than in control women. Significantly higher frequencies of rs3024735/G79A G/A and A/A (P< .001), rs3024719 G/A (P= .009), and rs3024731 A/A (P = .012), but not rs3024718 (P= .12), rs3024778 (P = .76), or rs3024772 (P= .27) genotype carriers were seen between IRM cases versus control women, respectively, and was linked with reduced PZ levels. Six-locus (rs3024718/rs3024719/rs3024778/rs3024731/rs3024735/rs3024772) PZhaplotypes analysis demonstrated increased frequency of GAGAAG and AGGTAG and reduced frequency of AGGTGC haplotypes in IRM cases, thereby conferring disease susceptibility and protective nature to these haplotypes, respectively. These results demonstrate that specific PZSNPs and haplotypes are significantly associated with IRM.

Participation of protein Z-dependent protease inhibitor and protein Z system in the pathomechanism of thrombotic complications

Thrombotic complications of unknown etiology remain a serious diagnostic and therapeutic problem. Occurrence of the inherited polymorphisms of genes encoding proteins involved in the coagulation cascade is one of the possible causes of these complications. In recent years, protein Z (PZ) and PZ-dependent protease inhibitor (ZPI) have been added to the list of prothrombotic factors. PZ is a glycoprotein serving as a cofactor of ZPI, which is responsible for the inhibition of prothrombinase. Expression of the PZ gene is under the control of many transcriptional factors; several polymorphisms alternate the rate of gene expression. The present article describes the significance of the ZPI-PZ system in venous and arterial thrombosis, adverse pregnancy outcomes and antiphospholipid syndrome complications.

Perfusion CT in childhood stroke--initial observations and review of the literature

INTRODUCTION

To report the preliminary results of contrast-enhanced perfusion multi-detector CT for diagnoses of perfusion disturbances in children with clinical suspicion of stroke.

PATIENTS AND METHODS

Within the last two years emergency perfusion CT was performed in ten children (age: 8-17 years, male:female=3:7) for assessment of suspected childhood stroke. These intracranial perfusion CT, intracranial CT-digital subtraction angiography (CT-DSA) and extracranial CT-angiography (CTA) studies were retrospectively reviewed and compared with MRI, follow-up CT, catheter angiography and final clinical diagnosis. The total dose length product (DLP) for the entire examination was recorded. The image quality of perfusion CT-maps, CT-DSA and CTA were evaluated with a subjective three-point scale ranging from very good to non-diagnostic image quality rating perfusion disturbance, intracranial peripheral vessel depiction, and motion- or streak artifacts.

RESULTS

In nine of ten children perfusion CT showed no false positive or false negative results. In one of ten children suffering from migraine focal hypo-perfusion was read as perfusion impairment potentially indicating early stroke, but MRI and MRA follow-up were negative. Overall, perfusion-CT with CT-DSA was rated very good in 80% of cases for the detection of perfusion disturbances and vessel anatomy.

CONCLUSIONS

In comparison to standard CT, contrast-enhanced perfusion CT improves CTs' diagnostic capability in the emergency examination of children with a strong suspicion of ischemic cerebral infarction.