Abstract

Constitutional trisomy 8 is a relatively rare aneuploidy; most identified cases are mosaic with a normal cell line. The phenotype is highly variable from apparently normal to severe disability. The proportion of abnormal cells is dramatically different between tissues and the severity of the phenotype is not directly related to the level of mosaicism. Therefore, it is very difficult to provide a definitive prognosis. We report here a case of constitutional trisomy 8 mosaicism with agenesis of the corpus callosum, congenital heart disease and micrognathia. The trisomy 8 cell line was not detected by prenatal cytogenetic study. This is the fourth reported case of constitutional trisomy 8 mosaicism in Korea.

• Keywords: Constitutional trisomy 8;Mosaicism;Agenesis of the corpus callosum