Fluorescence in-situ hybridization studies using a whole chromosome 9
painting probe were performed on three individuals from two different
families, who carry a chromosome 9 variant with an extra band within t
he elongated 9qh region. The results confirm the euchromatic nature of
the extra band, and provide evidence that it is of chromosome 9 origi
n. This variant band, which may not be very rare, thus possibly result
s from a duplication of a segment of 9qh plus band p12 or part of band
q21.