Nico J. Leschot

Co-variables in first trimester maternal serum screening

The objective of this study was to determined the influence of maternal weight, maternal smoking habits, gravidity, parity and fetal gender on the level of maternal serum marker used in first trimester screening for Down syndrome. A total of 2449 singleton unaffected pregnancies from two centres were studied. Maternal serum free β‐human chorionic gonadotrophin (hCG) and α‐fetoprotein (AFP) concentrations had been measured in all pregnancies, and pregnancy associated plasma protein (PAPP)‐A levels had been measured in 924. All results were expressed as multiples of the gestation specific median (MoM) values after regression, using each centres own medians. Information on maternal weight was available in 2259 pregnancies, on self‐reported current cigarette smoking in 1364 (of whom 117 (8.6%) were smokers), on gravidity in 1371, parity in 1303 and fetal gender in 253. All three markers showed a statistically significant negative association with maternal weight (p<0.0005) and in the subsequent analyses MoM values were weight adjusted using standard methods. The median PAPP‐A level in smokers was 0.81 MoM, a significant reduction (p<0.005); free β‐hCG was also reduced (median 0.89 MoM) but not significantly (p=0.17), and AFP was unaltered. The median AFP level in primagravidas was highly significantly greater than that in gravid women (p<0.0005). In PAPP‐A the reverse effect was seen but it did not reach statistical significance (p=0.15) and there was no effect for free β‐hCG. Results of a similar magnitude and direction were found for parity. The median level of free β‐hCG was higher (p=0.0005), and the median AFP lower in female pregnancies. Maternal weight and, for PAPP‐A, maternal smoking are important first trimester screening co‐variables. Gravidity, parity and fetal gender also seem to influence one or more first trimester markers. Copyright

Early pregnancy screening for fetal aneuploidy with serum markers and nuchal translucency.

We determined the aneuploidy detection rate achievable by early pregnancy screening with pregnancy associated plasma protein (PAPP)‐A, free β human chorionic gonadotrophin (hCG) and ultrasound nuchal translucency (NT) measurement. Women having prenatal diagnosis were scanned, and a blood sample was taken and stored. Stored samples were tested and a total of 37 were found to have Down syndrome, 8 to have Edwards syndrome and 255 were controls. Results were expressed in multiples of the gestation‐specific median (MOM) value in the controls after regression and, for the serum markers, maternal weight adjustment. In Down syndrome the medians were for PAPP‐A 0.63 MOM (95 per cent confidence interval (CI) 0.45–0.87); free β‐hCG 1.88 MOM (1.33–2.66); and NT 2.34 MOM (1.70–3.22). Using these parameters the expected detection rate for a 5 per cent false‐positive rate for different marker combinations were: 55.3 per cent for PAPP‐A and free β‐hCG; 68.4 per cent for NT alone; and 84.6 per cent for PAPP‐A, free β‐hCG and NT. The median values for Edwards syndrome were: 0.17 MOM for PAPP‐A; 0.18 MOM for free β‐hCG; and 2.64 MOM for NT. Early pregnancy screening with the combined measurement of maternal serum PAPP‐A and free β‐hCG and fetal nuchal translucency could achieve a high Down syndrome detection rate. Copyright

Lessons from BWS twins: complex maternal and paternal hypomethylation and a common source of haematopoietic stem cells

The Beckwith–Wiedemann syndrome (BWS) is a growth disorder for which an increased frequency of monozygotic (MZ) twinning has been reported. With few exceptions, these twins are discordant for BWS and for females. Here, we describe the molecular and phenotypic analysis of 12 BWS twins and a triplet; seven twins are MZ, monochorionic and diamniotic, three twins are MZ, dichorionic and diamniotic and three twins are dizygotic. Twelve twins are female. In the majority of the twin pairs (11 of 13), the defect on chromosome 11p15 was hypomethylation of the paternal allele of DMR2. In 5 of 10 twins, there was additional hypomethylation of imprinted loci; in most cases, the loci affected were maternally methylated, but in two cases, hypomethylation of the paternally methylated DLK1 and H19 DMRs was detected, a novel finding in BWS. In buccal swabs of the MZ twins who share a placenta, the defect was present only in the affected twin; comparable hypomethylation in lymphocytes was detected in both the twins. The level of hypomethylation reached levels below 25%. The exchange of blood cells through vascular connections cannot fully explain the degree of hypomethylation found in the blood cell of the non-affected twin. We propose an additional mechanism through which sharing of aberrant methylation patterns in discordant twins, limited to blood cells, might occur. In a BWS-discordant MZ triplet, an intermediate level of demethylation was found in one of the non-affected sibs; this child showed mild signs of BWS. This finding supports the theory that a methylation error proceeds and possibly triggers the twinning process.

Jejunal atresia related to the use of methylene blue in genetic amniocentesis in twins

Objective To calculate the incidence of jenunal atresia in newborns in The Netherlands. To study the relation between the occurrence of jejunal atresia and genetic amniocentesis to determine a possible iatrogenic cause for the unexpected high incidence of this anomaly in twins.

Reduced copy number of DAZ genes in subfertile and infertile men

OBJECTIVE(S) To determine the copy number and identity of the DAZ genes on the Y chromosomes of infertile patients. DESIGN Prospective study. SETTING University medical center. PATIENT(S) One hundred and thirty-nine patients with male factor infertility. INTERVENTION(S) The separate genes were detected by polymerase chain reaction (PCR) digestion assays of sequence family variants in leukocyte DNA and by fluorescence in situ hybridization of interphase nuclei and chromatin fibers. MAIN OUTCOME MEASURE(S) Number of DAZ genes present. RESULT(S) One hundred twenty-nine patients had four genes, 6 patients had two genes, and 4 patients had none. Three patients had a deletion of the two proximal DAZ genes, and three were missing both distal genes. Semen analysis showed a less severe phenotype in patients with only two DAZ genes compared with patients missing all four genes. CONCLUSION(S) In six patients, two different partial deletions were found that were not detected by PCR with conventional markers. One patient with an AZFb deletion appeared to also have a partial AZFc deletion that was not detected by routine PCR. Phenotypic differences between patients with different deletions suggest a dose effect of the DAZ genes.

Chorionic villi sampling: cytogenetic and clinical findings in 500 pregnancies

The cytogenetic findings were analysed in a series of 500 pregnancies in which chorionic villi sampling was performed. In all cases a direct method was used, karyotyping being successful in 481 cases (96.2%). The main indication for sampling was maternal age over 36 (412 cases; 82.4%). Abnormal laboratory findings resulted in 24 terminations of pregnancy (4.8%); in addition five unexpected balanced chromosome rearrangements were detected. Twelve of 15 cytogenetic discrepancies were detected at amniocentesis, two after termination, and one at spontaneous abortion. Complete follow up data were available for the first 250 patients, among whom nine pregnancies (3.6%) ended in spontaneous abortion before the 20th week. There were no false negative findings. Seventy additional chromosome studies were performed because of failure of chorionic villi sampling or equivocal results, or for confirmation. Counselling before chorionic villi sampling should include the possibility that subsequent amniocentesis may be needed should mosaicism or other unexpected abnormalities be found. The success rate and accuracy of karyotyping chorionic villi samples by the direct method are acceptable but distinctly less than those of karyotyping cultured amniotic fluid cells.

Enrichment, identification and analysis of fetal cells from maternal blood: evaluation of a prenatal diagnosis system

In this study we evaluated the performance of a system for the enrichment, identification and analysis of fetal cells in maternal peripheral blood.

A comparison of counselee and counselor satisfaction in reproductive genetic counseling

Important insights in the process of genetic counseling can be provided by establishing levels of satisfaction. The aim of our study was to compare counselees’ and counselors’ satisfaction with the initial consultation in reproductive genetic counseling and to gain insight into the factors associated with their contentment. One hundred and fifty‐one women and 11 counselors participated in this study. Pre‐test questionnaires included counselees’ socio‐demographic, physical and psychological characteristics, i.e. their degree of worry, expectations, preferred participation in decision making and experienced degree of control. Post‐visit questionnaires asked for counselees’ and counselors’ satisfaction, counselees’ participation in decision making and counselees’ Perceived Personal Control (PPC). Little difference was found between counselees’ and counselors’ overall visit‐specific satisfaction (mean 79 vs 74, respectively, on a visual analogue scale from 0 to 100). The correlation between counselees’ and counselors’ satisfaction was medium sized (r = 0.26, p < 0.01). Counselees’ satisfaction was positively associated with being pregnant and with their post‐visit PPC. Counselors’ satisfaction was positively associated with counselees’ post‐visit PPC. No other counselee and counselor related variables appeared to be associated with satisfaction, nor was the duration of the consultation. Our findings suggest that, although both groups were satisfied with the consultation, counselees and counselors do not always have equal perceptions of the consultation process and may form their evaluation in different ways. In the assessment of quality of care, evaluation of both counselees’ and counselors’ satisfaction deserves more attention.

Perspectives of couples with high risk of transmitting genetic disorders

OBJECTIVE To investigate the preference for preimplantation genetic diagnosis (PGD) as an alternative to prenatal diagnosis (PND) in a large group of couples representing a wide array of genetic disorders. We also investigated the couples familiarity with PGD and presented time trade-off scenarios for PGD versus PND, as PGD treatment is regularly accompanied by waiting lists. DESIGN Questionnaire study. SETTING Patient organizations representing genetic disorders. PATIENT(S) A total of 210 couples carrying genetic disorders. MAIN OUTCOME MEASURE(S) Preference for PGD or PND and familiarity with PGD in carrier couples. RESULT(S) Fifteen organizations representing 38 genetic disorders agreed to participate. Nine hundred eighty-three couples responded. In total 210 couples were in their reproductive years (women 18-40 years) and had a desire to conceive. Ninety couples (42%) had never heard of PGD. After they were informed, 127 couples (60%) wanted to have diagnostic testing (PND or PGD) performed. Ninety-four (74%) of these couples preferred testing with PGD. When no waiting list was used 102 couples (80%) preferred PGD. With a 2-year waiting list for PGD, 58 couples (46%) would opt for PGD. CONCLUSION(S) Many carrier couples are unaware of the existence of PGD. When informed, most couples prefer PGD more than PND. The preference for PGD decreases with longer waiting lists.

Genetic counseling for familial conditions during pregnancy: an analysis of patient characteristics

Reproductive genetic counseling for a familial genetic risk factor preferably takes place before conception. However, of the women with a family history of genetic conditions who attend our department of clinical genetics, about 10–20% attend for the first time during a pregnancy. The current study aims to explore patient‐related factors that may affect this late timing of reproductive genetic counseling. Consecutive pregnant (n = 100) and non‐pregnant (n = 84) women visiting the department of clinical genetics for a genetic risk factor which was not age related completed a questionnaire immediately prior to the consultation. The questionnaire asked for (a) background characteristics, i.e. socio‐demographic, obstetric, and disease characteristics (b) cognitive factors, i.e. initiative of referral, knowledge of the risk factor involved, risk perception, worry, child wish, attitudes toward abortion, and preferred participation in decision making, and (c) reasons for the timing of the consultation and for seeking genetic counseling. Pregnant women appeared to be higher educated, considered their children more often as healthy and were less often affected themselves, as compared to non‐pregnant women. They also estimated their chance of having an affected child as lower, and they worried less. Furthermore, the initiative for referral was taken less often by the pregnant woman herself and more often by a medical worker. There were no major differences between the two study groups in knowledge, perceived severity of the risk factor, child wish, attitudes toward abortion, desired participation in decision making, and reasons to seek genetic counseling. Women indicated no specific reasons for their timing of referral for reproductive genetic counseling, e.g. during vs before pregnancy. Our data suggest that this timing of referral is not influenced predominantly by the womens level of knowledge. Rather, womens estimation of genetic risks and their degree of worry, which may be in accordance with the actual risk figures, seem to play a role in seeking genetic counseling. Although further studies are required, a more active role of health care providers seems warranted if we want to prevent genetic counseling for familial genetic conditions during pregnancy as much as possible.