Noonan syndrome

Fabrice Cuillier, MD*, Kathleen Comalli Dillon, BA, RDMS**, J.L.Alessandri, MD***

*  Department of Gynecology, Félix Guyon Hospital, 97400 Saint-Denis, Ile de la Réunion, France.
**  Diagnostic Medical Sonographer, Medical writer/editor, 727 N Webster St #B, Petaluma, CA 94952, California, USA.
*** Department of Neonatology, Félix Guyon Hospital, 97400 Saint-Denis, Ile de la Réunion, France.

Case report

A 28-year-old, G1P0 patient, with non-contributive family or personal history, came for the first visit to our department at 25 weeks of gestation. Increased amount of the amniotic fluid and bilateral pyelectasis were noted.

Ultrasound examination at 12 weeks of gestation revealed normal nuchal translucency (1 mm, CRL = 60 mm). At 22 weeks of gestation, ultrasound investigation of the fetus was normal and no anomalies were observed.

Our ultrasound examination at 25 weeks of gestation revealed the following:

  • Normal facial profile, normal looking ears
  • Normal brain anatomy
  • Normal looking extremities and hands and feet
  • Normal heart anatomy (25 and 30 weeks)
  • Increased amount of the amniotic fluid
  • Bilateral pyelectasis
  • Bilateral cryptorchidism

At 30 weeks of gestation, amniocentesis was done, revealing a normal karyotype (46, XX), the Kleihauer-Betke test was negative.

Our differential diagnoses included a metabolic or genetic anomaly (Noonan syndrome); but the heart was normal during all the pregnancy.  At 36 weeks and 38 weeks the findings were the same. The neonate was delivered at 39 weeks of gestation with normal Apgar score of 10 and 10 in the first and fifth minutes, without cyanosis. Postnatal echocardiography showed a normal heart, and the mother and baby left the unit on the day four.

The patient returned six days later. The neonate had severe dyspnea. Hypertrophic cardiomegaly was observed, without hyperechoic atrioventricular valves and with no cardiac insufficiency. 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 1, Case 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.

Images 1,2: Images show fetal profile with mild prefrontal edema.


Images 3,4: 3D images of the fetal face with no obvious abnormality.


Images 5,6: Axial and sagittal view of both kidneys showing bilateral pyelectasis.


Images 7,8
: Image 7 shows the increased amount of the amniotic fluid. Image 8 shows a detail of the fetal mouth and nostrils.


Images 9,10: Image 9 shows 3D image of both ears with no apparent malformation. Image 10 shows a sagittal view of the brain with normal corpus callosum.


Images 11,12
: Image 11 shows a normal looking hands and fingers. Image 12 shows male gender, testicles are not inside the scrotum, cryptorchidism.


Image 13: Left outflow tract and a normal 4-chamber view.


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