Mosaicism with a normal cell line (N) and an unbalanced autosomal structura
l rearrangement (UASR) is rare. This report describes a case of a newborn f
emale with a karyotype of 46,XX,der(4)t(4;15)(q35;q22)/46,XX. Molecular cyt
ogenetic analysis confirmed the origin of the derivative chromosome 4, Here
we discuss this case as well as other cases of mosaic karyotypes involving
N/UASR, (C) 1999 Wiley-Liss, Inc.