Problems posed by prenatal diagnosis of abdominal wall malformations

The authors present 6 observations of in utero detected abdominal wall defect : 2 laparoschisis and 4 omphaloceles. In three cases the diagnosis have been done prior week 20, by systematic AFP assay for amniocentesis performed for cytogenetic or metabolic reasons; the pregnancy was terminated. In three other cases, the pregnancy was complicated by hydramnios after week 30; amniocentesis for AFP and echography were performed to detect fetal malformations after associated with hydramnios. The detected abdominal wall anomaly was not alone: two fetus had an abnormal caryotype (trisomy 18), three other presented a polymalformative syndrome, a Beckwith-Wiedemann syndrome was discussed for the last child. The in utero diagnosis of omphalocele or laparoschisis implicates difficulties for genetic counselling, particularly if the diagnosis is done prior week 20. These anomalies can be treated with surgical management, but frequency of associated malformations must be underlined. it is important for genetic counselling to know the family history, the amniotic fluid cells caryotype, and an ultrasound scanning performed to reveal any other malformations.     

Ultrasonic prenatal diagnosis of the Jarcho-Levin syndrome

The Jarcho-Levin syndrome is an autosomal recessive disease characterized by spinal and rib malformations (spondylocostal dysplasia). The case reported concerns a fetus with a dorsal spine angulation noted at the 15th week of gestation. A more accurate ultrasound study performed at 20 weeks revealed shortness of the neck and thorax, irregular ribs and vertebrae and absence of other visceral abnormalities. The karyotype was normal. Therapeutic abortion proposed was finally accepted by both parents at 27 weeks. The diagnosis was confirmed by post mortem radiography. No parental consanguinity was noted.     

Ethical considerations in prenatal diagnosis.

Prenatal diagnostic testing raises a number of important ethical issues, some related to diagnostic testing in general and others related to the special circumstances of pregnancy. These issues are most effectively addressed in the context of a broader understanding of the goals of prenatal diagnosis. Our dual obligations--to the pregnant woman and to the fetus--have an important influence on the goals of testing. Testing seldom leads to treatment beneficial to the fetus, but more often can be beneficial to the pregnant woman, particularly if the information provided enhances her ability to make sound decisions about reproductive matters. The process of prenatal diagnostic testing can, however, limit a woman''s sense of control over the decisions made about her pregnancy. It can also provide an opportunity for third parties to become involved in what are usually considered private matters. It is therefore important that the process of testing include adequate counseling and follow-up and that the patient''s confidence be respected. As prenatal diagnostic technology expands, both in terms of patients to be tested and diagnoses to be sought, society will face difficult questions concerning access to testing and the justification for its use.     

Confined chorionic mosaicism in prenatal diagnosis

Summary Confined chorionic mosaicism, detected commonly on chorionic villus sampling (CVS) and occasionally in cultured amniotic fluid cells, is described in five pregnancies that showed confined chorionic mosaicism for trisomies 12, 13, 14, 17 and a marker chromosome. Cytogenetic findings in these pregnancies support the conclusion that within chorion some chromosomal mosaicism are confined to the trophectoderm derivatives while others to the extra-embryonic mesoderm. The etiology of confined chorionic mosaicism is discussed in relation to a significant role of multiple cell lineages contributing to the early development of placenta. The need is indicated for the use of both direct and long-term cultures in CVS prenatal diagnosis, and for the confirmatory testing of fetal blood or amniotic fluid in cases where mosaicism is detected in chorionic villi.     

Cytogenetic analysis in prenatal diagnosis.

Chromosome analysis is the single most frequent test used in laboratory prenatal diagnostic studies. I summarize the current status of the field, including diagnostic problems in the laboratory and the clinical problems associated with communicating unexpected laboratory findings. I explore the effect of molecular genetics on these issues and its possible future effects on the entire practice of prenatal diagnosis as it relates to the risk for chromosome nondisjunction (trisomy). I also discuss the use of cytogenetic analysis in the prenatal diagnosis of certain inherited genetic diseases.