Persistence of nuchal edema and distended jugular lymphatic sacs in Noonan syndrome.
OBJECTIVE
Noonan syndrome is one of the most common genetic syndromes manifesting at birth. Still, it is diagnosed late, often during infancy. Diagnosis is difficult because prenatal ultrasound findings are unspecific and the dysmorphias after birth can be subtle.


METHODS
Two women were referred to our university hospital because of an increased nuchal translucency in the first trimester of pregnancy. Further ultrasound examination showed the bilateral presence of distended jugular lymph sacs. Karyotyping revealed euploidy in both fetuses. The second trimester ultrasound scan showed a persistence of the jugular lymph sacs together with a nuchal fold, indicating a disturbed lymphatic development. There were no other anomalies. In 1 case the jugular lymph sacs containing newly formed lymph node tissue remained visible until 35 weeks' gestation. Both newborns were diagnosed with Noonan syndrome after birth. Postnatal echocardiography revealed a mild pulmonary stenosis.


CONCLUSIONS
Distension of the jugular lymph sacs is known to cause nuchal edema and normally resolves after the first trimester. In case of persistence of the jugular lymphatic sacs beyond the second trimester of pregnancy, the diagnosis of Noonan syndrome and subsequent DNA testing should be considered.
Bekker
Mireille N
MN
Department of Obstetrics and Gynecology, VU University Medical Center, Amsterdam, The Netherlands. mn.bekker@vumc.nl
Go
Atti T J I
AT
van Vugt
John M G
JM
D000328:Adult; D015193:Chorionic Villi Sampling; D004487:Edema / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000196:embryology; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000235:genetics / Q000473:pathology; D005820:Genetic Testing; D005865:Gestational Age; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D007621:Karyotyping; D050498:Live Birth; D008208:Lymphatic System / Q000002:abnormalities* / Q000000981:diagnostic imaging; D009154:Mutation; D009634:Noonan Syndrome / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000196:embryology / Q000473:pathology; D048208:Nuchal Translucency Measurement; D011247:Pregnancy; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000235:genetics; D016216:Ultrasonography, Prenatal / Q000379:methods
D047908:Intracellular Signaling Peptides and Proteins; C516724:PTPN11 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases