DUPLICATION OF 8P23.1 - A CYTOGENETIC ANOMALY WITH NO ESTABLISHED CLINICAL-SIGNIFICANCE

We present seven families with a cytogenetic duplication of the short arm of chromosome 8 at band 8p23.1. The duplication has been transmitt ed from parents to offspring in four of the seven families. In three f amilies, the source of the extra material and its euchromatic origin w ere established using FISH with a YAC which was mapped to 8p23.1 and a whole chromosome paint for chromosome 8. FISH signals from this YAC w ere significantly larger on the duplicated chromosome compared with th e normal chromosome in all six family members tested. Comparative geno mic hybridisation (CGH) on a representative subject was consistent wit h these results. The families were ascertained for a variety of mostly incidental reasons including prenatal diagnosis for advanced maternal age. The transmission of this duplication by multiple phenotypically normal family members with no history of reproductive loss suggests th e existence of a novel class of 8p23.1 duplications, which can be rega rded as euchromatic variants or duplications with no phenotypic effect .