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Resources > Educational Tools > Clinical Vignettes > Prental Case Presentation

Clinical Vignettes

Vignette 1: Prenatal Case Presentation

This case illustrates the clinical usefulness of prenatal array CGH.

A 21-year-old woman was referred at 16 weeks’ gestation because alobar holoprosencephaly (HPE) was observed on ultrasound examination. The woman’s obstetrical history revealed one spontaneous abortion and one pregnancy terminated at 15 weeks’ gestation following detection of alobar HPE. Family history showed that the father’s brother had failure to thrive and autistic features. Karyotype analysis on the mother and fetus was normal.

Microarray analysis of the fetus showed a single copy-number loss of 7.7Mb at 7q36.1q36.3 (Figure 1) encompassing the SHH gene, deletion of which is associated with holoprosencephaly 3, and a single-copy gain of 4.4Mb at 8q24.3 (Figure 2). FISH confirmed both abnormalities (Figure 3). FISH analysis of the parents showed a balanced t(7;8)(q36.3;q24.3) in the father (Figure 4). Detection of the paternal balanced translocation indicates significant risk for recurrence in this family.

Vignette 1 Figures

Figure 1. Microarray plots for a single-copy loss of 7q36.1q36.3. Each clone represented on the array is arranged along the x-axis according to its location on chromosome 7 with the most distal/telomeric p-arm clones on the left and the most distal/telomeric q-arm clones on the right. The blue line represents the ratios for each clone from the first slide for the patient (control Cy5/patient Cy3). (A) Plot for a normal chromosome 7 showing a log2 raio of 0 for all clones. (B) Plot showing a single-copy loss at 7q36.1q36.3, ~7.7mb.

Figure 2. Microarray plots showing single-copy gain of 8q24.3. Plots are arranged as in Figure 1. (A). Plot for a normal chromosome 8 showing log2 ratio of 0 for all clones. (B) Plot showing single-copy gain of 8q24.3 ~4.4Mb in size.

Figure 3. FISH reults for fetus. (A) FISH showing deletion of 7q36.# encompassing the SHH gene. The clone from 7q36.6 is labeled in red, and a chromosome 7 centromere probe is labeled in green as a control. No red signal is present on the derivative 7. (B) FISH showing duplication of 8q24.3. The clone from 8q24.3 is labeled in red, and a chromosome 8 centromere probe is labeled in green as a control. An extra red signal is present on the dericative 7.

Figure 4. Paternal FISH showing balanced t(7;8)(q36.3;q24.3). (A) The probe from 7q36.3 is labeled in red, and centromere probes are labeled in green as a control. A red signal is present on the derivative 8. (B) The probe from 8q24.3 is labeled in red, and centromere probes are labeled in green as a control. A red signal is present on the derivative 7.