No evidence for increased prevalence of JAK2 V617F in women with a history of recurrent miscarriage

Contribution of JAK2 and STAT3 variants to the genetic susceptibility of recurrent spontaneous miscarriage in a Tunisian population

AIMS

Th1 and Th2 balance is crucial for maintenance of pregnancy, and intracellular JAK and STAT proteins significantly contribute to it. In view of evidence linking JAK2 and STAT3 variants with recurrent spontaneous miscarriage (RSM), here we investigated the association of JAK2 (rs2230724) and STAT3 (rs1053023 and rs1053004) to RSM susceptibility in Tunisians.

SUBJECTS AND METHODS

A retrospective case-control study. Subjects comprised 235 RSM cases and 235 control subjects. JAK2 and STAT3 were genotyped by the allelic discrimination method.

RESULTS

STAT3 rs1053023 and, to a lower extent, rs1053004 were significantly associated with RSM under the additive and dominant, but not recessive models. This remained significant after adjustment for the covariates age, smoking, and gravida. In contrast to STAT3 variants, JAK2 rs2230724 was not associated with RSM under any of the genetic models tested. Two-locus STAT3 (rs1053023/rs1053004) haplotype analysis revealed increased frequency of the C/G haplotype in patients with RSM. Multivariate regression analysis confirmed the association of C/G haplotype with RSM (p=0.001; odds ratio=2.01; 95% confidence interval=1.32-3.07), thus conferring RSM susceptibility nature. These differences remained significant after applying the Bonferroni correction for multiple testing (Pc=0.004).

CONCLUSIONS

STAT3 rs1053023, more so than the STAT3 rs1053004 or JAK2 rs2230724 polymorphisms, is associated with RSM risk.

Contribution of JAK2 and STAT3 variants to the genetic susceptibility of recurrent miscarriage among Bahraini and Tunisian Arabs

We investigated the contribution of JAK2 rs2203724 and STAT3 rs1053023 and rs1053004 to the susceptibility of idiopathic recurrent miscarriage (IRM) in Bahraini (246 cases and 279 controls) and Tunisian (235 cases and 235 controls) Arabs. The distribution of JAK2 rs2203724 and STAT3 rs1053023 genotypes were in Hardy-Weinberg equilibrium (HWE) in both communities, while mild deviation from HWE was noted for rs1053004 in Tunisians but not Bahraini. JAK2 rs2203724 was not associated with IRM in either community, while STAT3 rs1053023 was positively associated with IRM in both Bahraini and Tunisian women. STAT3 rs1053004 displayed mixed association: it was positively associated with IRM in Bahraini (P < 0.001), but not Tunisian women (P = 0.10). Genotype association confirmed the association of both STAT3 variants with IRM under additive, dominant, and recessive models, while the association of STAT3 rs1053023 was seen under additive and dominant, but not recessive models in Tunisians. The contribution of JAK2 and STAT3 variants to IRM susceptibility must be evaluated regarding specific variants, and the ethnic/racial background.

Genetics of recurrent miscarriage: challenges, current knowledge, future directions

Recurrent miscarriage (RM) occurs in 1-3% of couples aiming at childbirth. Due to multifactorial etiology the clinical diagnosis of RM varies. The design of genetic/"omics" studies to identify genes and biological mechanisms involved in pathogenesis of RM has challenges as there are several options in defining the study subjects (female patient and/or couple with miscarriages, fetus/placenta) and controls. An ideal study would attempt a trio-design focusing on both partners as well as pregnancies of the couple. Application of genetic association studies focusing on pre-selected candidate genes with potential pathological effect in RM show limitations. Polymorphisms in ∼100 genes have been investigated and association with RM is often inconclusive or negative. Also, implication of prognostic molecular diagnostic tests in clinical practice exhibits uncertainties. Future directions in investigating biomolecular risk factors for RM rely on integrating alternative approaches (SNPs, copy number variations, gene/protein expression, epigenetic regulation) in studies of single genes as well as whole-genome analysis. This would be enhanced by collaborative network between research centers and RM clinics.

Myeloproliferative disorders in pregnancy

This article reviews pregnancy outcome in women diagnosed with a myeloproliferative neoplasm (MPN), and discusses possible risk markers and the pathogenesis of poor pregnancy outcome. An outline of the key factors regarding the diagnosis and management of MPN in women of reproductive potential is followed by a description of the authors' management strategy for standard and high-risk pregnancy in MPN patients.

Impact of common thrombophilias and JAK2 V617F on pregnancy outcomes in unselected Italian women

BACKGROUND

Although an association between thrombophilias and adverse pregnancy outcome has been shown, the influence of the most common inherited thrombophilias and the somatic mutation JAK2 V617F in determining an adverse outcome is questioned.

OBJECTIVES

We examined the contribution of the factor V Leiden (FVL), the prothrombin G20210A (PTm) and the somatic JAK2 V617F mutations to adverse pregnancy outcome in an unselected cohort of pregnant women.

PATIENTS/METHODS

During the study period, 5345 pregnant women were admitted to the 14 hospitals of the five provinces of the Campania region (Italy). Of these, 3097 samples were investigated and obstetric history collected. The presence of the FVL, PTm, and JAK2 V617F mutation was prospectively determined by polymerase chain reaction followed by TaqMan SNP genotyping assays.

RESULTS AND CONCLUSIONS

We identified 119 (3.8%) women that carried FVL and 138 (4.4%) with the PTm. Only 4 (0.1%) women carried both mutations. Only one woman tested positive for the JAK2 V617F somatic mutation. The prevalence of a previous history of an adverse pregnancy outcome was similar in women with common thrombophilias as compared to those without. In the current pregnancy, there was no association of any of the genetic markers considered with any of the adverse outcomes investigated. Carriership of FVL or PTm showed a positive trend with delivery of a small for gestational age newborn (OR: 1.5, 95% CI: 0.9-2.5). Pregnancy outcomes in asymptomatic women with inherited thrombophilias are often uneventful. Therefore, in women at low-risk of an adverse pregnancy, neither screening for common thrombophilias nor administration of routine thromboprophylaxis are warranted.

JAK2 mutation and thrombosis in the myeloproliferative neoplasms

The clinical course of the classic myeloproliferative neoplasms (MPNs) is burdened by an increased rate of cardiovascular events, which are the major cause of mortality. Age and history of thrombosis are the criteria used to stratify patients to the most appropriate therapeutic options. However, the mechanisms ultimately responsible for the increased thrombotic tendency have not yet been elucidated; abnormalities of blood cell count, neutrophil and platelet activation, and a state of hypercoagulability can all occur. Recurrent mutations in JAK2 or MPL have been described in MPNs and serve as disease markers. There is also evidence that a JAK2V617F mutant state represents an independent factor associated with thrombosis, and abnormalities of cell function attributable to JAK2V617F have been characterized. It is hoped that elucidation of the role mutant JAK2 plays in MPNs will improve our understanding of the pathophysiology of thrombosis and eventually result in improved patient treatment using molecularly targeted drugs.