A dominantly inherited cytogenetic anomaly: a possible cell division mutant.

Short-term lymphocyte cultures from three unrelated patients showed an increased frequency of mitoses with separated centromeres and splayed chromatids in the presence of colcemid. We refer to this phenomenon as premature centromere division (PCD). In two of the three patients the frequency of PCD in lymphocytes decreased when colcemid was omitted prior to harvest but was still higher than controls, whereas in the third patient, the frequency appeared unchanged. Cultured fibroblasts from the latter patient exhibited increased tetraploidy and multinucleated cells. Transmission of the trait in the three families was compatible with autosomal dominant inheritance. Time lapse cinemicrographic studies on fibroblasts from one patient demonstrate a shortened metaphase time, suggesting that the separation of chromatids observed in this patient may indeed be premature. The nature of the mutation(s) and phenotype correlation if any is unknown.