Premature centromere splitting in a presumptive mild form of Roberts syndrome.

Cytogenetic investigations performed on lymphocytes from a 29-year-old woman with no severe anomalies, allowed us to recognize a mild form of Roberts syndrome. The proposita's metaphases showed a consistent centromere splitting, especially affecting chromosomes 16, 19, 21, and 22. This centromere separation sequence seems to be unique to Roberts syndrome cells. The experiments also showed that no diffusible factor, involved in the mechanism of sister chromatid pairing-disjunction, exists.