Effectiveness and costs of non-invasive foetal RHD genotyping in rhesus-D negative mothers: a French multicentric two-arm study of 850 women.

BACKGROUND: The determination of foetal Rhesus D (RHD) status allows appropriate use of IgRh prophylaxis by restricting its use to cases of RHD feto-maternal incompatibilities. There is a degree of uncertainty about the cost-effectiveness of foetal RHD determination, yet screening programs are being introduced into clinical practice in many countries. This paper evaluates the impact of non-invasive foetal Rhesus D (RHD) status determination on the costs of managing RHD-negative pregnant women and on the appropriate use of anti-D prophylaxis in a large sample of RHD-negative pregnant women using individual prospectively collected clinical and economic data. METHODS: A prospective two-armed trial of RHD negative pregnant women was performed in 11 French Obstetric Departments. Non-invasive foetal RHD genotyping was performed before 26 weeks' gestation in the experimental arm whereas the control arm participants received usual care. The costs associated with patient management in relation to their RHD negative status (biological tests, anti-D prophylaxis and visits) were calculated from inclusion to the end of the postpartum period. The costs of hospital admissions during pregnancy and delivery were also determined. RESULTS: A total of 949 patients were included by 11 centres between 2009 and 2012, and 850 completed follow-up, including medical and biological monitoring. Patients were separated into two groups: the genotyping group (n=515) and the control group (n=335). The cost of the genotyping was estimated at 140 euros per test. The total mean cost per patient was estimated at €3,259 (SD ± 1,120) and €3,004 (SD ± 1,004) in the genotyping and control groups respectively. The cost of delivery represented three quarters of the total cost in both groups. The performance of managing appropriately RHD negative anti-D prophylaxis was 88% in the genotyping group, versus 65% in the control group. Using the costs related to RHD status (biological tests, anti-D immunoglobulin injections and visits) the incremental cost-effectiveness ratio (ICER) was calculated to be €578 for each percentage gain in women receiving appropriate management. CONCLUSION: Early knowledge of the RHD status of the foetus using non-invasive foetal RHD genotyping significantly improved the management of RHD negative pregnancies with a small increase in cost. TRIAL REGISTRATION: Clinical trials registry- NCT00832962 -13 January 2009 - retrospectively registered.

Mutational Spectrum in Holoprosencephaly Shows That FGF is a New Major Signaling Pathway.

Holoprosencephaly (HPE) is the most common congenital cerebral malformation in humans, characterized by impaired forebrain cleavage and midline facial anomalies. It presents a high heterogeneity, both in clinics and genetics. We have developed a novel targeted next-generation sequencing (NGS) assay and screened a cohort of 257 HPE patients. Mutations with high confidence in their deleterious effect were identified in approximately 24% of the cases and were held for diagnosis, whereas variants of uncertain significance were identified in 10% of cases. This study provides a new classification of genes that are involved in HPE. SHH, ZIC2, and SIX3 remain the top genes in term of frequency with GLI2, and are followed by FGF8 and FGFR1. The three minor HPE genes identified by our study are DLL1, DISP1, and SUFU. Here, we demonstrate that fibroblast growth factor signaling must now be considered a major pathway involved in HPE. Interestingly, several cases of double mutations were found and argue for a polygenic inheritance of HPE. Altogether, it supports that the implementation of NGS in HPE diagnosis is required to improve genetic counseling.

NEK1 and DYNC2H1 are both involved in short rib polydactyly Majewski type but not in Beemer Langer cases.

BACKGROUND: The lethal short rib polydactyly syndromes (SRP type I-IV) are characterised by notably short ribs, short limbs, polydactyly, multiple anomalies of major organs, and autosomal recessive mode of inheritance. Among them, SRP type II (Majewski; MIM 263520) is characterised by short ovoid tibiae or tibial agenesis and is radiographically closely related to SRP type IV (Beemer-Langer; MIM 269860) which is distinguished by bowed radii and ulnae and relatively well tubulated tibiae. NEK1 mutations have been recently identified in SRP type II. Double heterozygosity for mutations in both NEK1 and DYNC2H1 in one SRP type II case supported possible digenic diallelic inheritance. METHODS: The aim of this study was to screen DYNC2H1 and NEK1 in 13 SRP type II cases and seven SRP type IV cases. It was not possible to screen DYNC2H1 in two patients due to insufficient amount of DNA. RESULTS: The study identified homozygous NEK1 mutations in 5/13 SRP type II and compound heterozygous DYNC2H1 mutations in 4/12 cases. Finally, NEK1 and DYNC2H1 were excluded in 3/12 SRP type II and in all SRP type IV cases. The main difference between the mutation positive SRP type II group and the mutation negative SRP type II group was the presence of holoprosencephaly and polymycrogyria in the mutation negative group. CONCLUSION: This study confirms that NEK1 is one gene causing SRP type II but also reports mutations in DYNC2H1, expanding the phenotypic spectrum of DYNC2H1 mutations. The exclusion of NEK1 and DYNC2H1 in 3/12 SRP type II and in all SRP type IV cases further support genetic heterogeneity.

Spectrum of mutations in the renin-angiotensin system genes in autosomal recessive renal tubular dysgenesis.

Autosomal recessive renal tubular dysgenesis (RTD) is a severe disorder of renal tubular development characterized by early onset and persistent fetal anuria leading to oligohydramnios and the Potter sequence, associated with skull ossification defects. Early death occurs in most cases from anuria, pulmonary hypoplasia, and refractory arterial hypotension. The disease is linked to mutations in the genes encoding several components of the renin-angiotensin system (RAS): AGT (angiotensinogen), REN (renin), ACE (angiotensin-converting enzyme), and AGTR1 (angiotensin II receptor type 1). Here, we review the series of 54 distinct mutations identified in 48 unrelated families. Most of them are novel and ACE mutations are the most frequent, observed in two-thirds of families (64.6%). The severity of the clinical course was similar whatever the mutated gene, which underlines the importance of a functional RAS in the maintenance of blood pressure and renal blood flow during the life of a human fetus. Renal hypoperfusion, whether genetic or secondary to a variety of diseases, precludes the normal development/ differentiation of proximal tubules. The identification of the disease on the basis of precise clinical and histological analyses and the characterization of the genetic defects allow genetic counseling and early prenatal diagnosis.

Circulating microRNAs as clinical biomarkers in the predictions of pregnancy complications.

Predicting pregnancy complications is a major topic for clinicians and biologists for maternal and fetal monitoring. Noninvasive biomarkers in maternal blood such as circulating microRNAs (miRNAs) are promising molecules to predict pregnancy disorders. miRNAs are noncoding short RNAs that regulate mRNA expression by repressing the translation or cleaving the transcript. miRNAs are released to the extracellular systemic circulation via exosomes. The discovery of plasma- or serum-derived miRNAs and of free-circulating exosomes that contain miRNAs provides useful information about the physiological or pathophysiological roles of the miRNAs. Specific placental miRNAs are present in maternal plasma in different ways depending on whether the pregnancy is normal or pathological or if there is no pregnancy. This paper focuses on placental miRNAs and extracellular miRNAs to the placenta whose misregulation could lead to pregnancy complications.

Enhanced prevalence of plasmatic soluble MHC class I chain-related molecule in vascular pregnancy diseases.

The major histocompatibility complex class I related chain (MIC) is a stress-inducible protein modulating the function of immune natural killer (NK) cells, a major leukocyte subset involved in proper trophoblast invasion and spiral artery remodeling. Aim of the study was to evaluate whether upregulation of soluble MIC (sMIC) may reflect immune disorders associated to vascular pregnancy diseases (VPD). sMIC was more frequently detected in the plasma of women with a diagnostic of VPD (32%) than in normal term-matched pregnancies (1.6%, P < 0.0001), with highest prevalence in intrauterine fetal death (IUDF, 44%) and vascular intrauterine growth restriction (IUGR, 39%). sMIC levels were higher in preeclampsia (PE) than in IUFD (P < 0.01) and vascular IUGR (P < 0.05). sMIC detection was associated with bilateral early diastolic uterine notches (P = 0.037), thrombocytopenia (P = 0.03), and high proteinuria (P = 0.03) in PE and with the vascular etiology of IUGR (P = 0.0038). Incubation of sMIC-positive PE plasma resulted in downregulation of NKG2D expression and NK cell-mediated IFN-γ production in vitro. Our work thus suggests that detection of sMIC molecule in maternal plasma may constitute a hallmark of altered maternal immune functions that contributes to vascular disorders that complicate pregnancy, notably by impairing NK-cell mediated production of IFN-γ, an essential cytokine favoring vascular modeling.

Fetal RhD genotyping by real time quantitative PCR in maternal plasma of RhD-negative pregnant women from the Sahel of Tunisia.

OBJECTIVE: The aim of this study was to evaluate the diagnostic value of RhD fetal genotyping from the plasma of RhD-negative pregnant women. METHODS: We analysed the plasma samples of 65 pregnant women. DNA quantification was done using real time quantitative PCR (RQ-PCR) in multiplex targeting multiple RhD exons 5, 7 and 10, with a standardized pool of plasmid calibrators. Results were compared with serological analysis of cord blood after delivery. RESULTS: Fetal RhD status was predicted with 95.38% accuracy from maternal plasma of pregnant women in the 11(th) to 40(th) weeks of gestation. One false positive but no false negative results were found. Thus the sensitivity of the assay was 100% and the specificity was 94.44 %. CONCLUSION: The present data demonstrates that the fetal RhD genotyping approach could be achieved efficiently with RQ-PCR for RhD-negative tunisian pregnant women.