Pulmonary hypoplasia in neonatal hypophosphatasia.

Morphological, biophysical, and biochemical parameters of lung growth were studied at autopsy on a male infant with hypophosphatasia who died with asphyxia immediately after birth. The lungs were hypoplastic because of a marked decrease in airspace formation but lung maturation was normal for gestational age by all the parameters used. Diaphragmatic development, assessed by weight and fiber measurement, was in keeping with the decreased chest size. The proposed mechanism for this late onset type of pulmonary hypoplasia, attributed to decreased thoracic volume, is correlated with antenatal ultrasonographic observations of normal fetal breathing movements in the affected infant.