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2017-10-29  Noonan syndrome  © Fabrice Cuillier  www.TheFetus.net

Noonan syndrome
Cuillier F., MD.*, Doray B. Pr.**, J.L.Alessandri, MD.***
 
*  Department of Gynecology, Félix Guyon Hospital, 97400 Saint-Denis, Ile de la Réunion, France. 
**  Department of Cyto-genetic, Félix Guyon Hospital, 97400 Saint-Denis, Ile de la Réunion, France. 
*** Department of Neonatology, Félix Guyon Hospital, 97400 Saint-Denis, Ile de la Réunion, France.
 

Case report

A 30-year-old patient (G1P0), with non-contributive family or personal history, came for the first time to our department at 12 weeks of pregnancy. Ultrasound examination at 12 WG revealed normal nuchal translucency (1 mm, CRL = 60 mm, triple test 1/10000).
At 22 and 32 weeks of gestations, ultrasound examination of the fetus was normal and no anomalies were observed. 

The patient was examined one more time at 36 weeks of pregnancy and the ultrasound examination revealed the following findings.
  • Polyhydramnios, without intestinal obstruction.
  • Normal facial profile, normal looking ears with normal size.  
  • Normal brain anatomy with normal corpus callosus. 
  • Normal looking extremities, hands and feet. 
  • A right isolated hydrothorax.
  • Normal heart anatomy, with normal valve. 
  • Possible bilateral cryptorchidism and micropenis. 
At 37 weeks of pregnancy amniocentesis was done and the result was normal karyotype (46, XX), Kleihauer-Betke test was negative and MCA velocimetry was normal.

Our differential diagnoses included a metabolic or genetic anomaly (Noonan syndrome); but the heart was normal during the whole pregnancy, in particular pulmonary artery. At 38 weeks, findings were the same. 

The neonate was delivered at 39 weeks with normal Apgar 10/10 in the first and fifth minutes, without cyanosis. Postnatal echocardiography showed a normal heart. On the other hand, the baby was hypotonic and he had severe dyspnea. Isolated hypertrophic cardiomegaly was observed, without hyperechoic atrio-ventricular valves and with no cardiac insufficiency. Four thoracocentesis were done (chylothorax). 

The baby was examined again and the clinical appearance of the neonate demonstrated some features of Noonan syndrome such as low-set, dysplastic ears, widely spread nipples, and exophthalmos.   

Genetic examination confirmed the diagnosis of Noonan syndrome via study of gene PTPN11. 

In contrast to our two published Noonan syndrome cases (
Case 1Case 2), in this case, cardiomyopathy was not revealed prenatally but a few days, after birth.  
At 8 month of life, the baby developed supravalvular pulmonary stenosis and left ventricular hypertrophic myocardiopathy, characteristic of Noonan syndrome.

Image 1: p
olyhydramnios, without intestinal obstruction.





Images 2, 3 and 4
: normal facial profile and normal looking extremities, hands and feet.

  



Images 5 and 6
right isolated hydrothorax.

 



Videos 1 and 2
: normal heart anatomy without pulmonary artery stenosis.

 



Image 7
: possible bilateral cryptorchidism and micropenis.


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