The current case of the week is a case of aneuploidy, Trisomy 9.
Introduction
Trisomy 9 is a very rare chromosomal abnormality, which has a wide range of symptoms. The ultrasound findings can vary but they usually include central nervous system, craniofacial, cardiac, skeletal and genitourinary abnormalities. The fetuses which survive to term are usually mosaics, the majority of the affected pregnancies results in spontaneous abortion at early pregnancy.
Case
The presented fetal anomaly is a case of 25-year-old primipara which was referred for an ultrasound examination at 26 weeks for a suspicion of a central nervous system abnormality. She was otherwise healthy, the pregnancy was uncomplicated, no history of teratogens. During the ultrasound examination at 26 weeks we found symmetric IUGR (intrauterine growth restriction) corresponding to 22 weeks of gestation. Fetus showed multiple abnormalities:
Central nervous system: agenesis of vermis and dysgenesis of corpus callosum, thick nuchal fold
Craniofacial: hypertelorism, micrognathia
Cardiovascular: AV canal, transposition of the great vessels, single umbilical artery
Genitourinary: pyelectasis
Skeletal: brachycephaly, rockker-bottom foot.
Our differential diagnosis included Trisomy 13 and 18, we did a karyotyping from the amniotic fluid and the result was Trisomy 9. Patient delivered preterm, dead fetus, no autopsy was performed. We examined the karyotype of the patents as well. The maternal karyotype showed a reciprocal balanced translocation between chromosome 15 and 9, 46, XX t(15:9). We are planning on consulting the patient regarding the future pregnancy.
Image 1,2: Vermian agenesis, Dandy-Walker malformation, note the nuchal fold thickenning.