A new mutation in the AFP gene responsible for a total absence of alpha feto-protein on second trimester maternal serum screening for Down syndrome.

Alpha feto-protein (AFP) is a major plasma protein produced by the yolk sac and the liver during the fetal period. During the second trimester of pregnancy, APF and betahCG serum concentrations are commonly used for screening Down syndrome. AFP deficiency is rare (estimated to be 1/105,000 newborns) and only one sequence alteration has previously been reported in the AFP gene. We report a new mutation in exon 5 of the AFP gene, leading to a total absence of AFP on 2nd-trimester maternal serum screening for Down syndrome, confirmed on the amniotic fluid. Despite this, fetal development and birth were normal. After PCR-amplification, the whole AFP gene was sequenced. The new mutation was a guanine to adenine transition in position 543 creating a premature stop codon in position 181. In order to search for eventual modifications of the amniotic fluid profile, proteins were separated by electrophoresis and compared with 10 normal amniotic fluids sampled at the same developmental age (18 weeks). In the amniotic fluid of our patient albumin rate was reduced whereas alpha1 and beta protein fractions were increased, suggesting that AFP deficiency may modify the distribution of protein fractions. This observation emphasizes the complex molecular mechanisms of compensation of serum protein deficiency. Studies on other families with AFP deficiency are necessary to confirm this observation.

Enlightenment about the new Architect-i2000 estradiol (Abbott Laboratories) immunoassay during in vitro fertilization.

OBJECTIVE: We assessed a new estradiol (E2) immunoassay on the Architect-i2000 (Abbott Laboratories) for monitoring ovulation stimulation for IVF-ET and re-establishing clinical cut-off points. The method has been modified to improve E2 measurements especially at normal and low concentrations. DESIGN AND METHOD: E2 was determined for 552 samples, from 83 women, presenting normal follicular status and undergoing 100 cycles of IVF treatment. We assessed the value of this assay for down-regulation of E2 concentration limit using gonadoliberin-releasing hormone agonist (GnRHa), and monitoring of the ovarian hyperstimulation, expected range of E2 per mature follicle prior to the administration of exogenous hCG and day 3 concentration limit. We compared results with our routine method (E2-6II Advia-Centaur; Siemens-Diagnostics) for which decision-making values were known. RESULTS: Considering E2 concentrations obtained with the new Architect-i2000 assay for patients treated with GnRHa for 2 weeks, the cutoff-point for ovarian down-regulation should be set down at 110 pmol/L to maintain 100% of sensitivity. Considering day 3 concentration limit determination, results were not significantly different from those obtained with our routine method. The mean E2 values per mature follicle fell into the range generally expected. CONCLUSION: E2 determination with the new E2 Architect-i2000 assay could be used to monitor ovulation, in patients undergoing IVF-ET, in combination with transvaginal ultrasound.

Prediction of preeclampsia or intrauterine growth restriction by second trimester serum screening and uterine Doppler velocimetry.

OBJECTIVE: To assess the performance of screening for preeclampsia and intrauterine growth restriction by combining second trimester maternal serum screening and uterine Doppler ultrasound. METHODS: A cohort of 2,615 women underwent both maternal serum screening (using human chorionic gonadotropin (hCG) and alpha-fetoprotein (AFP)), and second trimester uterine artery Doppler. The sensitivity, specificity and predictive value of different combinations of both tests were compared. RESULTS: The mean values for hCG and AFP were significantly higher in women with subsequent preeclampsia (p < 0.0003 and p < 0.03, respectively). Taking into account obstetrical history, hCG and AFP levels, notching on uterine artery Doppler and parity, the adjusted odds ratios were significantly higher for a high level of hCG for preeclampsia, intrauterine growth restriction (IUGR) and pregnancy-induced hypertension. AFP level >1.5 MoM (multiples of the median) was significantly correlated with subsequent IUGR. The presence of a uterine notch was associated with a significantly higher risk of both preeclampsia and IUGR. The combination of an elevated serum level and the presence of a uterine notch had a positive predictive value (PPV) for preeclampsia of 25 and 21% for hCG and AFP, respectively. The combination of a bilateral notch with a low level of hCG or a high level of AFP had a PPV for IUGR of 50 and 43%, respectively. The sensitivity of the different tests ranged from 2 to 40%. CONCLUSION: The combination of serum markers and abnormal uterine Doppler ultrasound improves the identification of women at risk for subsequent pregnancy complications. These results should encourage care providers to perform a uterine Doppler ultrasound when serum markers are abnormal. However, the sensitivity of these tests is too low to provide an efficient generalized screening.

First-trimester screening for Down syndrome in France combining fetal nuchal translucency measurement and biochemical markers.

BACKGROUND: In France, there is a strictly regulated National Screening Programme for Down syndrome, based on second-trimester maternal serum markers. A prospective study of nuchal translucency together with retrospective evaluation of maternal serum markers was carried out to inform decisions on whether to move the programme to the first trimester. METHODS: Between January 1998 and June 2001, all women who presented for their prenatal care at 12 participating maternity units were, regardless of age, invited to provide a blood sample and to attend for an NT scan at 11 to 13 weeks. The results were used to derive Gaussian distribution parameters. Detection and false-positive rates were computed in two ways: statistical modelling and directly. The cut-off risk was 1 in 250 at term. RESULTS: A total of 5694 women with singleton pregnancies were screened including 26 with Down syndrome and 24 with other aneuploidies. The model-predicted detection and false-positive rates for combined ultrasound and serum screening were 81 and 4.5% compared to 64 and 6.0% for ultrasound alone. The directly observed rates were 73 and 4.7%, compared to 62 and 5.0% respectively. CONCLUSION: In France, first-trimester screening with nuchal translucency and maternal serum markers is likely to achieve a high screening efficiency. This has important implications for the national screening policy.

Severe preeclampsia is associated with high inhibin A levels and normal leptin levels at 7 to 13 weeks into pregnancy.

OBJECTIVE: The purpose of this study was to determine whether maternal serum inhibin A and leptin concentrations changed in the first trimester of pregnancy in patients in whom severe preeclampsia subsequently developed. STUDY DESIGN: Blood samples were collected prospectively from patients during the first trimester of prenatal care. Patients in whom severe preeclampsia with no evidence of glucose intolerance or gestational diabetes mellitus subsequently developed were identified (study group, 30 patients) and matched with control subjects in a 1:2 ratio (control group, 60 patients). Inhibin A and leptin concentrations were determined in these first-trimester serum samples for both the study and control groups. RESULTS: Leptin levels were correlated highly with body mass index in both groups but were not correlated with the subsequent onset of preeclampsia. Serum inhibin A concentrations were significantly higher in women in whom preeclampsia subsequently developed than in women in whom it did not. With a specific cutoff value, the estimated odds for severe preeclampsia were almost five times higher in women with high inhibin A concentrations than in women with normal levels (odds ratio, 4.93; 95% CI, 1.83, 13.28). CONCLUSION: High serum inhibin A levels in the first trimester of pregnancy could be used as an early risk marker for preeclampsia.

Comparison of day 3 FSH serum values as determined by six different immunoassays.

BACKGROUND: The accurate assessment of FSH concentration is important for evaluating ovarian function prior to IVF. However, a number of different assay techniques are currently in use, leading to inconsistencies in the hormone data being reported. To address this problem, we measured FSH concentration using a number of commercially available systems. METHODS: Day 3 serum FSH levels were measured in 215 healthy fertile women using six different immunoassays: Coatria (125)I (Bio-Mérieux), ACS-180 (Bayer Diagnostics), Advia-Centaur (Bayer Diagnostics), Vitros ECi (Ortho-Clinical Diagnostics), Architect i2000 (Abbott) and Elecsys 2010 (Roche Diagnostics). RESULTS: According to the immunoassay, means +/- SD of FSH concentrations were: 6.5 +/- 2.2 mIU/ml for Coatria (125)I, 6.8 +/- 2.7 mIU/ml for Advia-Centaur, 6.7 +/- 3.0 mIU/ml for Vitros ECi, 7.6 +/- 3.0 mIU/ml for ACS-180, 8.2 +/- 3.3 mIU/ml for Architect i2000 and 8.8 +/- 3.0 mIU/ml for Elecsys 2010. CONCLUSION: Day 3 FSH values determined by six different immunoassays were significantly different (P < 0.01, paired t-test). Physicians must take care when interpreting results from different clinical laboratories.