Ultrastructural Features of the Granulocytes in Down's Syndrome

The granulocytes of 9 patients with Down's syndrome (DS) were examined for morphological abnormalities. Electron microscope examination showed abnormalities in the nucleus, such as pockets, bridges, appendices and fibrillar bodies in 25–57 % of the cells as compared to similar, but less conspicuous findings in 5–10 % of the granulocytes of 5 controls. The similarity of these ultrastructural malformations to those described in different forms of leukaemia is stressed. Since chromosomal abnormalities exist in both DS and leukaemia, the possibility that they are the cause for the ultrastructural alterations is discussed.