Table 1

Diagnostic features of Noonan syndrome (NS) and the relative importance of these features3

FeatureA=majorB=minor
1.FacialTypical face*Suggestive face
2.CardiacPulmonary valve stenosis and/or hypertrophic cardiomyopathyOther cardiac defect
3.Height<3rd centile<10th centile
4.Chest wallPectus carinatum/excavatumBroad thorax
5.Family historyFirst-degree relative with definite NSFirst-degree relative suggestive of NS
6.OtherMild developmental delay, cryptorchidism AND lymphatic dysplasiaMild developmental delay, cryptorchidism OR lymphatic dysplasia
Definitive NS=Criterion 1A (typical face)
PLUS
Criterion 1B (suggestive face)
PLUS
1×major criterion
(2A‒6A)
2×minor criteria
(2B‒6B)
2×major criteria
(2A‒6A)
3×minor criteria
(2B‒6B)
  • *Facial features of NS vary over time and may have only subtle differences.