Ultrastructural Studies of the May-Hegglin Anomaly

One case of May-Hegglin’s anomaly has been described with characteristic findings present also in the mother of the reported case. The propositus showed typical stigmata of the condition: characteristic crescentic, pyroninophilic cytoplasmic patches in a high proportion of polymorphonuclear leukocytes, thrombocytopenia, and giant platelets. The patient’s mother, however, had characteristic patches in only 6 per cent of polymorphonuclear leukocytes and had giant platelets, but was not thrombocytopenic. This is the first patient reported to have such a small proportion of affected polymorphonuclear leukocytes, and suggests that there is variable expression of this genetically determined error of cell differentiation. Other family members did not show hematologic abnormalities.

The ultrastructure of leukocytes and platelets from the propositus was investigated, and it was found that:

1. No ultrastructural abnormalities were identified in the lymphocytes and monocytes.

2. Polymorphonuclear neutrophiles had irregular cytoplasmic areas which lacked specific granules and which contained small granules probably glycogen, 50 Å. diameter filaments, and amorphous densities.

3. The fibrils found in the characteristic patches probably consist of RNA.

4. Platelets have apparently normal ultrastructure, but are twice the normal diameter.