Rhombencephalosynapsis in a severely polymalformed fetus with non-mosaic tetrasomy 9p, in intracytoplasmic-sperm-injection pregnancy.

CASE REPORT: A fetus with rhombencephalosynapsis and prenatally diagnosed tetrasomy 9p is reported. Chromosomal analysis from amniocyte culture revealed non-mosaic supernumerary chromosome identified as isochromosome 9p (9p24-->q13::q13-->p24). Ultrasound scan revealed intrauterine growth retardation, renal anomalies, cardiac anomalies, ventriculomegaly, and agenesis of cerebellar vermis with fusion of the cerebellar hemispheres. CONCLUSION: Although most cases of cerebellar vermis agenesis in tetrasomy 9p are described with cystic malformation such as Dandy-Walker anomaly, our case indicates that this chromosomal disorder should be taken into account in fetuses with the development of cystic and non-cystic malformations of cerebellar vermis and posterior fossa.

Fetal facial profile in Pallister-Killian syndrome.

Pallister-Killian syndrome (PKS) is a sporadic chromosomal anomaly, caused by a tissue-specific mosaic distribution of an additional isochromosome 12p. About 60 cases of prenatal diagnosis of PKS have been reported. Only 1 case of PKS is described on the basis of prenatal screening, presenting increased nuchal translucency. An abnormal fetal facial profile is described prenatally as sonographic evidence of PKS. We report a case of prenatal diagnosis in a fetus undergoing second-level scan due to positive triple screen with ultrasound features of PKS.

Cystic hygroma and mid-trimester maternal serum screening.

OBJECTIVE: To investigate the relationship between maternal serum screening markers and pregnancy outcome in fetuses with cystic hygroma at 15-18 weeks of gestation. STUDY DESIGN: We retrospectively reviewed case-notes of 34 consecutive singleton fetuses with cystic hygroma referred at 15-18 weeks of gestation. All cases had maternal blood sampled for triple screening at the time of the ultrasound scan. RESULTS: In total, 62% of fetuses with cystic hygroma had abnormal chromosome complements and 80% had a poor outcome. Six fetuses presenting normal values of human chorionic gonadotropin (0.5-2.5 MoM [multiples of the median]), serum alpha-fetoprotein (0.5-2.5 MoM) and unconjugated estriol (>0.5 MoM), normal karyotype and absence of associated structural anomalies had an uneventful outcome. CONCLUSIONS: Our data demonstrated that cystic hygroma at 15-18 weeks has a strong association with chromosomal abnormalities. In euploid fetuses, maternal serum screening results may have a role in the diagnostic work-up of the pregnancy.

Lack of correlation between elevated maternal serum hCG during second-trimester biochemical screening and fetal congenital anomaly.

OBJECTIVE: Isolated elevations in midtrimester maternal serum human chorionic gonadotrophin concentrations (MShCG) have been reported to be associated with a substantially increased likelihood of fetal congenital malformations. The reported malformations included a wide range of organ systems, originating at different embryologic developmental stages. The purpose of our study was to determine the significance of an isolated elevated MShCG (>2.5 MoM) in midtrimester for the detection of fetal structural anomalies in a large population. METHODS: Among 10,144 women who underwent a biochemical triple screen at 15 to 18 weeks' gestation, 463 patients, who had an elevated MShCG, but normal alpha-fetoprotein (AFP) and unconjugated estriol (uE3) levels, were identified. Patients with an integrated calculated Down syndrome risk above 1:250 were excluded. Only nonsmokers, at ages <35 years, without a history of prior fetal anomalies were included. The control group consisted of 463 patients with normal serum analyte concentrations and Down syndrome risks below 1:250, who were matched for maternal age and date of biochemical screen. All patients underwent a detailed genetic sonogram in which an anatomic survey and multiple 'soft markers' for aneuploidy were looked for. Newborns were examined by a senior pediatrician trained in dysmorphology. RESULTS: MShCG levels were 3.18 +/- 0.72 versus 0.99 +/- 0.43 MoM (p < 0.0001) in study and control groups respectively. Sonography revealed 8 versus 6 cases of major congenital anomalies among the 463 patients of their respective groups, and 39 versus 36 sonographic 'soft markers' for aneuploidy. Fetal karyotyping and neonatal examination for dysmorphology revealed 6 chromosomal anomalies (4 Down syndrome; 2 Turner syndrome) among the 8 major malformations in the study group, but none in the controls (p < 0.0001). Three of the 39 fetuses with 'soft markers' and elevated MShCG were found to have trisomy 21. CONCLUSION: Isolated elevation of MShCG does not confer an increased risk of fetal congenital anomalies other than chromosomal abnormalities. However, elevated MShCG levels in combination with sonographic 'soft markers' for aneuploidy were associated with a high incidence of chromosomal anomalies, despite a normal biochemical triple screen risk estimate.