Biomedical subjects
Bernd Eiben
Publications and source records attributed to Bernd Eiben.
Situs ambiguus in a female fetus with balanced (X;21) translocation--evidence for functional nullisomy of the ZIC3 gene?
The human ZIC3 gene has been mapped to Xq26.2, the visceral heterotaxy locus HTX1, and has been shown to be mutated in X-linked situs ambiguus and/or complex heart defects. We report on a female fetus with situs ambiguus, asplenia and corrected transposition of the great arteries, displaying a (X;21) translocation. The balanced state of the t(X;21)(q26;p13) was verified by FISH on metaphase chromosomes of the fetus using DOP-PCR products of the microdissected der(21) and Xq-subtelomere specific sequences, and by PRINS with beta-satellite specific sequences. Examination with polymorphic markers flanking ZIC3 on DOP-PCR products of the microdissected der(21) chromosome evidenced that the complete copy of the ZIC3 gene was translocated to chromosome 21. Mutations in the fetal and parental ZIC3 genes were excluded by sequencing. Paternal origin of the der(X) and der(21) chromosomes was confirmed by use of polymorphic microsatellite markers from chromosome 21 and from the chromosomal region Xq26, respectively. X chromosome inactivation analysis using a PCR of a polymorphic (CAG)(n) repeat in the first exon of the androgen receptor gene showed a completely skewed X inactivation pattern with the paternal X as the active X chromosome, thus excluding functional disomy of distal Xq. A positional effect caused by the balanced (X;21) translocation may be responsible for functional nullisomy of ZIC3 and thus explain the situs and cardiac abnormalities in the fetus.
First-trimester screening: an overview.
An improvement in prenatal screening for chromosomal defects has been achieved by combining sonography and biochemical markers. Analyzing markers taken from maternal blood such as pregnancy-associated plasma protein A and free beta-human chorionic gonadotropin in combination with the ultrasound marker nuchal translucency provides detection rates of 90% for the most important chromosomal anomalies. In addition, nuchal translucency is a marker for severe heart defects. This report discusses the potential of new markers such as the nasal bone.
Outcomes of pregnancies diagnosed with Klinefelter syndrome: the possible influence of health professionals.
OBJECTIVE: To describe the association between the outcomes of pregnancies diagnosed with Klinefelter syndrome (KS) and the specialty of the health professional providing pre- and post-diagnostic counselling. METHOD: Data were extracted from the case notes of the 111 cases of KS diagnosed prenatally between 1986 and 1997 in eight geographical regions in five European countries. The data extracted included: outcome of pregnancy, maternal age, social class, parity, gestational age at diagnosis, year of diagnosis and specialties of the health professionals conducting pre- and post-diagnosis consultations. RESULTS: The overall termination rate was 44% (49/111: 95% confidence interval: 35 to 54). Using multivariable logistic regression analysis, the only significant predictor of continuation of the pregnancy was the specialties of the health professionals conducting post-diagnosis counselling: the affected pregnancy was more likely to continue when post-diagnosis counselling involved only a genetics specialist (relative risk: 2.42 (1.14 to 5.92)). CONCLUSION: There is an association between whether or not a woman terminates a pregnancy affected by an unfamiliar fetal anomaly and the professional background of the health professional providing post-diagnostic counselling. The causal nature of this association remains to be determined.