Rapid aneuploidy diagnosis by multiplex ligation-dependent probe amplification using uncultured amniocytes in pregnancy with major fetal structural abnormalities

Prenatal diagnosis and molecular cytogenetic characterization of chromosome 22q11.2 deletion syndrome associated with congenital heart defects

OBJECTIVE

To report prenatal diagnosis of 22q11.2 deletion syndrome in a pregnancy with congenital heart defects in the fetus.

CASE REPORT

A 26-year-old, primigravid woman was referred for counseling at 24 weeks of gestation because of abnormal ultrasound findings of fetal congenital heart defects. The Level II ultrasound revealed a singleton fetus with heart defects including overriding aorta, small pulmonary artery, and ventricular septal defect. Cordocentesis was performed. The DNA extracted from the cord blood was analyzed by multiplex ligation-dependent amplification (MLPA). The MLPA showed deletion in the DiGeorge syndrome (DGS) critical region of chromosome 22 low copy number repeat (LCR) 22-A∼C. Conventional cytogenetic analysis revealed a normal male karyotype. Repeated amniocentesis and cordocentesis were performed. Whole-genome array comparative genomic hybridization (aCGH) on cord blood was performed. aCGH detected a 3.07-Mb deletion at 22q11.21. Conventional cytogenetic analysis of cultured amniocytes revealed a karyotype 46,XY. Metaphase fluorescence in situ hybridization (FISH) analysis on cultured amniocytes confirmed an interstitial 22q11.2 deletion.

CONCLUSION

Prenatal ultrasound findings of congenital heart defects indicate that the fetuses are at increased risk for chromosome abnormalities. Studies for 22q11.2 deletion syndrome should be considered adjunct to conventional karyotyping. Although FISH has become a standard procedure for diagnosis of 22q11.2 deletion syndrome, MLPA can potentially diagnose a broader spectrum of abnormalities, and aCGH analysis has the advantage of refining the 22q11.2 deletion breakpoints and detecting uncharacterized chromosome rearrangements or genomic imbalances.

Prenatal diagnosis of fetal gastroschisis using three-dimensional ultrasound: comparison between the 20th and 21st centuries

OBJECTIVE

In order to compare the trends and improvements of prenatal diagnosis of gastroschisis, we herein retrospectively reviewed our cases of fetal gastroschisis detected by three-dimensional ultrasound (3D US) between the two centuries.

MATERIALS AND METHODS

We reviewed our computer database of prenatal diagnosis on gastroschisis in National Cheng Kung University Hospital from October 1994 to November 2011. All the fetuses were initially scanned by two-dimensional (2D) US to locate the region of interest (ROI). Then, the 3D probe was used to scan all the ROI systematically and mechanically, and all the images were stored on laser discs for further 3D visualization and reconstruction. To compare the characteristics at prenatal diagnosis of gastroschisis between the 20th and 21st centuries in our hospital, the Chi-square test and Student t test were used. The p values less than 0.05 and 0.1 were considered statistically significant.

RESULTS

In total, 26 fetuses with gastroschisis were depicted by 3D US in utero (10 cases were diagnosed in the 20th century and 16 cases in the 21st century). The ranges of gestational age at prenatal diagnosis of gastroschisis by 3D US in the 20th century were between 14 and 34 weeks (mean: 21.6 weeks) and between 14 and 33 weeks (mean: 21.9 weeks) in the 21st century. Moreover, seven cases (70%) were diagnosed before the third trimester in the 20th century, whereas 13 cases (81%) were diagnosed before the third trimester in the 21st century.

CONCLUSION

Although without statistical significance, higher prenatal diagnosis rate before the third trimester in the 21st century was noted. The improvement of 3D US has remarkable advantages in adding novel visual depiction of a 3D lesion of a 3D fetus in 3D US after reconstruction and thus assists substantially in prenatal diagnosis, genetic consultation, and perinatal management of gastroschisis.

Prenatal diagnosis and molecular cytogenetic characterization of mosaicism for a small supernumerary marker chromosome derived from chromosome 22 associated with cat eye syndrome

We present prenatal diagnosis of mosaicism for a small supernumerary marker chromosome (sSMC) derived from chromosome 22 associated with cat eye syndrome (CES) using cultured amniocytes in a pregnancy with fetal microcephaly, intrauterine growth restriction, left renal hypoplasia, total anomalous pulmonary venous return with dominant right heart and right ear deformity. The sSMC was bisatellited and dicentric, and was characterized by multiplex ligation-dependent probe amplification (MLPA) and array comparative genomic hybridization (aCGH). The SALSA MLPA P250-B1 DiGeorge Probemix showed duplication of gene dosage in the CES region. aCGH showed a 1.26-Mb duplication at 22q11.1-q11.21 encompassing CECR1-CECR7. The sSMC was likely inv dup(22) (q11.21). Prenatal diagnosis of an sSMC(22) at amniocentesis should alert CES. MLPA, aCGH and fetal ultrasound are useful for rapid diagnosis of CES in case of prenatally detected sSMC(22).