Search :     
Articles » Aneuploidy » Trisomy 18

2006-07-24-15 Trisomy 18 © Cuillier www.thefetus.net/


Trisomy 18

Fabrice Cuillier, MD

Department of Gynecology, Félix Guyon’ Hospital, Ile de la Réunion, France

This is a 30-year-old, G8P7, referred to our department due to an omphalocele and a cardiac malformation diagnosed at 35 weeks.  The ultrasound findings were:

  • Complex cardiac anomaly. This fetus had a situs solitus. The four-chamber-view showed a large right ventricle, with a left morphology. A right atrium was connected to this "right" ventricle. An atrophic morphological right ventricle (the left ventricle) was seen under a small left atrium. The foramen ovale valve was on the left near a small left atrium. The aorta was connected directly to the right ventricle (with left morphology). The pulmonary artery seemed connected to the left ventricle, which was atrophic. The diameter of the aorta was 7-8 mm and the pulmonary artery measured 3 mm. The dimension of the right and left pulmonary arteries were 2 mm. A normal cardiac sinusal rhythm was present. A diagnosis of atria-ventricular discordance was made, without ventriculoarterial discordance. There was no septal defect. Doppler investigation of the mitral and tricuspid valves revealed a regurgitation jet during systole. The mitral valve was dysplastic, thick, with abnormal movements.
  • Cardiomegaly:  The cardio-thoracic ratio was 0.6. The right wall was thick (5 mm to 6 mm). No other evidence of congestive cardiac failure was observed.
  • Omphalocele (with liver)
  • Hypoplasia of cerebellar vermis
  • Clenched fingers, in particularly, on the right hand.  The left hand was always closed.
  • Umbilical cord seemed abnormal
  • Intrauterine growth restriction


A brain MRI was performed at 35 weeks and 3 days. The fetal brain anomaly was confirmed (hypoplasia of cerebellar vermis)). The face seemed normal. An amniotic fluid alpha-fetoprotein analysis and a karyoptype (trisomy 18) were performed. The couple decided to perform an interruption of pregnancy at 36 weeks.  The anatomopathological analysis was refused.

Note the aorta in red and the pulmonary artery in blue.

Note the omphalocele

The abnormal umbilical cord and the clenched fingers

Hypoplasia of cerebellar vermis

MRI images showing the hypoplasia of the cerebellar vermis

Help Support TheFetus.net :