Maternal age-specific risks for trisomies at 9—14 weeks' gestation

This study provides data on the incidence of fetal trisomies 21, 18, and 13 at 9–14 weeks' gestation in women aged 35–45 years and estimates of maternal age-specific risks in women aged 20–45 years. Our data from 5814 singleton pregnancies undergoing first-trimester karyotyping for the sole indication of maternal age ⩾ 35 years were combined with those from two previous reports and the incidence of the trisomies was calculated from a total of 15 793 pregnancies. Comparison of incidences at 9–14 weeks' gestation with published data at 15–20 weeks' gestation and in livebirths demonstrated that at birth the maternal age-specific incidence of trisomy 21 is 33 per cent lower than at 15–20 weeks' gestation and 54 per cent lower than at 9–14 weeks' gestation. Furthermore, the relative frequency of trisomies 18 and 13 decreases from 30 per cent at 9–14 weeks to 22 per cent at 15–20 weeks and 14 per cent at birth.     

MSAFP levels and oesophageal atresia

This study was undertaken to evaluate the relationship between maternal serum alpha-fetoprotein (MSAFP) levels and oesophageal atresia (OA). OA occurred in 16 fetuses of mothers who had an MSAFP test in the study interval. The multiple of the median (MOM) value for MSAFP averaged 1·54 ± 0·65 (range 0·5–2·9 MOM), which was significantly higher than the value seen in controls. The median MOM was 1·35. Using a cut-off of 2·5 MOM, the sensitivity of MSAFP for detecting OA was 19 per cent. Although OA should be considered in the differential diagnosis of an elevated MSAFP level, MSAFP cannot be considered an appropriate screening test for OA given the low sensitivity.     

Achondrogenesis type 2 diagnosed by transvaginal ultrasound at 12 weeks' gestation

Ultrasound examination at 12 weeks' gestation revealed severe generalised subcutaneous oedema in a pregnancy at risk for achondrogenesis type II. Transvaginal scanning confirmed the oedema and suggested abnormal limb development. The prenatal diagnosis was confirmed by X-ray examination after transvaginal termination.     

Prenatal diagnosis of 21-hydroxylase deficiency by rflp analysis of the 21-hydroxylase,complement C4, and HLA class II genes

In 19 pregnancies at risk for 21-hydroxylase deficiency (21OHD) in 18 families with at lea one affected child, prenatal diagnosis was performed by RFLP analysis using the enzymi Taq I and EcoRI and the DNA probes specific for the 21 OH genes, the closely linke complement C4 genes and the highly polymorphic HLA class II genes DRB, DQB, and DPI For fetal DNA analysis either chorionic villi or cultivated amniotic cells were used. In all 1 cases, a clear prenatal diagnosis was possible either with the 21OH probe alone or in mo cases, by combining the results of the different closely linked loci.     

Prenatal diagnosis of endocardial fibroelastosis

In a case of fetal heart failure caused by endocardial fibroelastosis, prenatal echocardiography clearly demonstrated; a thickened endocardium. We therefore suggest that an abnormal endocardium may be detected in utero by ultrasound, thus representing an important clue in the differential diagnosis of fetal nonimmune hydrops and in the evaluation of pregnancies at risk for endocardial fibroelastosis.     

Prenatal diagnosis for dystrophia myotonica using the polymerase chain reaction

The polymerase chain reaction has been used to detect an abundant class of short repeat DNA families of the form (dC-dA)n.(dG-dT)n, known as microsatellites. These units are found throughout the human genome and have been characterized for several loci including APOC2 on chromosome 19ql2-ql3.2. The locus APOC2 is linked to the gene for dystrophia myotonica and a microsatellite within this locus was used to derive polymorphisms in a family to predict the inheritance of the disease. Chorionic villus sampling (CVS) was performed at 151/2 weeks' gestation. Following DNA extraction from the CVS material and parental blood samples, microsatellite analysis was carried out by the polymerase chain reaction.     

Prenatal diagnosis of β-thalassaemia in Mediterranean populations by dot blot analysis with DNA amplification and allele specific oligonucleotide probes

In this study, we describe a simple strategy to detect β-thalassaemia mutations in prospective parents and to make prenatal diagnosis in pregnancies at risk in the Mediterranean population. Screening of prospective parents is carried out by dot blot analysis on enzymatically amplified DNA with a set of oligonucleotide probes complementary to the most common mutations in this population. Prenatal diagnosis is accomplished by the same procedure on enzymatically amplified amniocyte or trophoblast DNA. The main advantages of this procedure are the simplicity, sensitivity (0.05 μg of DNA), and rapidity (12–24 h). Further simplification is obtained by amplification of the DNA from crude amniotic cell lysate. The very low amount of fetal material necessary for this analysis eliminates the need to culture amniotic fluid cells and may decrease the fetal loss rate associated with trophoblast sampling. The number of specific DNA sequences obtained by the amplification procedure allowed us to use non-radioactive labelled oligonucleotide probes, which have several advantages compared to radioactive probes.     

Prenatal diagnosis of Opitz (BBB) syndrome in the second trimester by ultrasound detection of hypospadias and hypertelorism

Prenatal diagnosis in a kindred with the Opitz (BBB) syndrome is presented. The inheritance is consistent with either autosomal dominant inheritance with sex limited expression or X-linked inheritance. The abnormalities in the kindred consist of hypertelorism, hypospadias, ambiguous genitalia, urocolic fistula, imperforate anus, mental retardation, diaphragmatic hernia, and malrotation with volvulus. A male fetus at 19 weeks was found by ultrasound to have hypertelorism and hypospadias with a small phallus consistent with the syndrome. The diagnosis was confirmed by pathologic examination after pregnancy termination. This is the first report of prenatal diagnosis of Opitz syndrome by ultrasonographic demonstration of hypertelorism and hypospadias in the second trimester.