Trisomy 8 Mosaicism
Trisomy 8 mosaicism (T8M) is a chromosome disorder caused by the presence of a complete extra chromosome 8 in some cells of the body. The remaining cells have the usual number of 46 chromosomes, with two copies of chromosome 8 in each cell. Occasionally T8M is called Warkany syndrome after Dr Josef Warkany, the American paediatrician who first identified the condition and its cause in the 1960s. Full trisomy 8 – where all cells have an extra copy of chromosome 8 - is believed to be incompatible with survival, so babies and children in whom an extra chromosome 8 is found are believed to be always mosaic (Berry 1978; Chandley 1980; Jordan 1998; Karadima 1998).