Kniest dysplasia: neonatal death with necropsy.

We describe a premature female infant with Kniest dysplasia, who died shortly after birth. This appears to be the first autopsy performed in this condition. Manifestations included neonatal respiratory distress, large head, midface hypoplasia, flat nasal bridge, short nose, micrognathia, cleft palate, short neck, micromelia, and mildly bowed limbs. Roentgenologic findings included short, slightly bowed tubular bones with metaphyseal flare; mild platyspondyly, with vertical clefts of vertebral bodies; small iliac bones with increased acetabular angles; and inadequate ossification of pubic rami. Histopathologic findings of cartilage included focal "Swiss-cheese" pattern; disorganized physeal growth zone; and PAS-positive, diastase-resistant intracytoplasmic inclusions, which corresponded to finely granular material accumulated in dilated cisterns of rough endoplasmic reticulum.