Growth and development of lungs in siblings with nonimmune hydrops

Postmortem findings in the lungs of two siblings with nonimmune hydrops and lung hypoplasia are presented. In one, a girl, the hypoplasia was severe, with reduced numbers of airway generations and markedly reduced radial alveolar counts. In the other, a boy, the hypoplasia of both airway and alveolar development was mild. The reason for the difference in the growth of the lungs in these two children is unknown. The additional finding of Noonan's syndrome in the male sibling with mild hypoplasia and in the father is of interest.