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2015-06-05-22 Answer to the case of the week #397 © Grochal 

Answer to the case of the week #397

June 18, 2015 - July 02, 2015

Frantisek Grochal, MD1; Adriana Gátová, MD2; Jana Kršiaková, MD3.

1 Femicare, Center of prenatal ultrasonographic diagnostics, Kollarova 17A, 036 01 Martin, Slovak republic; 
2 AGAIA s.r.o., Zvolenská 4014, 036 01 Martin, Slovak Republic; 
3 Genetic department, M-Genetik, s.r.o., Martin, Slovak republic.

Case report

A 32-year-old primigravida, with non-contributive history, was sent to our office at 12 weeks of pregnancy due to abnormal fetal morphology of one of the two fetuses of monochorionic, diamniotic pregnancy. 

Our examination revealed following findings:

- monochorionic, diamniotic, twin pregnancy;
- female gender of both fetuses;
- normal amount of amniotic fluid in both compartments;

Fetus A

- increased nuchal translucency (7.5 mm, septate sonolucent nuchal edema) and abdominal skin edema;
- normal nasal bone; three-vessel umbilical cord;
- tricuspid regurgitation;
- absent ductus venosus.

Fetus B

- normal nuchal translucency (1.3 mm) and normal nasal bone
- single umbilical artery; the rest of the fetal morphology was normal;
- normal flow within ductus venosus.

Despite of the fact the pregnancy was monochorionic, the findings were suspected of the heterokaryotypic twin pregnancy with Turner syndrome of the fetus A.

The patient was sent to geneticist and invasive testing was indicated. Following amniocentesis and DNA study confirmed monozygotic heterokaryotypic twin pregnancy monosomy X (45,X0) of the fetus A and normal karyotype of the fetus B (46,XX).

Selective feticide of the fetus A by ultrasound-guided coagulation of the umbilical cord with bipolar forceps had been indicated, but was refused by the parents. 

At 20 weeks massive hydrops of the fetus A was present. The fetus A had occupied almost the whole space of the uterine cavity and had been compressing the normal fetus to the fundal part of the uterine cavity. One week later another ultrasonographic examination was done, but revealed intrauterine demise of both fetuses and pregnancy was terminated.

Chromosomal abnormality in one of the fetuses of a monozygotic twin pregnancy is rare, but has been described in literature several times [1, 2, 3]. This possibility should be taken into consideration in differential diagnostic process during evaluation of monozygotic twin pregnancies because some features of such pregnancy may imitate twin-to-twin transfusion syndrome. 

12 weeks

Images 1, 2, 3: 12 weeks of pregnancy; the images show thin inter-amniotic membrane, placenta and normal amount of the amniotic fluid in both compartments of the monochorionic, diamniotic twin pregnancy.


Images 4, 5, 6, and 7: 12 weeks of pregnancy; Fetus A; the images show increased nuchal translucency (7.5 mm, septate sonolucent nuchal edema) and abdominal skin edema of the fetus.



Image 8, and video 1: 12 weeks of pregnancy; Fetus A; the image 8 shows tricuspid regurgitation; the video 1 shows absent ductus venosus of the fetus A.


Image 9, and video 2: 12 weeks of pregnancy; Fetus A; the image 9 shows two umbilical arteries passing around empty urinary bladder; the video 2 shows normal female gender of the fetus A.


Images 10, 11, 12, 13, and 14: 12 weeks of pregnancy; Fetus B; the images show normal nuchal translucency, normal nasal bone, normally filled stomach, single umbilical artery, and normal flow within ductus venosus of the fetus B.



20 weeks

Image 15 and videos 3, 4: 20 weeks of pregnancy; Fetus A; massive hydrops of the fetus can be seen. 


Video 5 and videos 3, 4: 20 weeks of pregnancy; Fetus A; color Doppler 2D and 3D imaging showing absent ductus venosus of the fetus - umbilical vein after insertion to the abdomen has abnormal direction and connection to portal system). 



Videos 5, 6: 20 weeks of pregnancy; the video 5 shows hydrothorax and normal morphology of the fetus A; the video 6 shows normal thorax and four chamber view of the heart of the fetus B. 



1. Nieuwint A, Van Zalen-Sprock R, Hummel P, Pals G, Van Vugt J, Van Der Harten H, Heins Y, Madan K. 'Identical' twins with discordant karyotypes. Prenat Diagn. 1999 Jan;19(1):72-6. PubMed PMID: 10073913.
Bohec C, Douet-Guilbert N, Basinko A, Le Bris MJ, Marcorelles P, Audrézet MP, Tetefort R, Bages K, Collet M, Morel F, De Braekeleer M. Difficult diagnosis and management of an heterokaryotypic monochorionic twin pregnancy with discordant fetal sex and 45,X/47,XYY karyotypes. Fetal Pediatr Pathol. 2010;29(6):424-30. doi: 10.3109/15513815.2010.505630. PubMed PMID: 21043568.
3. Sepulveda W, Wong AE, Ocaranza M. Heterokaryotypic pregnancy: monozygotic 
monochorionic twins discordant for trisomy 13. Fetal Diagn Ther. 2010;28(2):109-13. doi: 10.1159/000309175. Epub 2010 May 21. PubMed PMID: 20501972.

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