Partial trisomy 1 due to a "shift" and probable location of the Duffy (Fy) locus.

Transposition of 1q31-1q32 from the q to p arm in a parent followed by crossing over resulted in a child with a duplication of this region. Concomitant C- and GTG-banding and genotyping were used to position the single crossover and to localize Fy to 1q2.