JUMPING TRANSLOCATION IN A PHENOTYPICALLY NORMAL FEMALE

''Jumping translocation'' (jt) refers to a rare type of chromosome mos aic. in which the same portion of a (donor) chomosome is translocated to different (recipient) chromosome sites. Jt have mainly been observe d in lymphocyte cultures of patients with hematologic malignancies. We report a phenotypically normal female carrying a mosaic of two cell l ines with the Xq26-qter segment translocated to the short arm of chrom osomes 15 or 21 in peripheral blood lymphocytes. In skin fibroblasts, only the X/21 translocation was detected. We speculate that recombinat ion between homologous repetitive sequences on non-homologous human ac rocentrics may be the cause of such chromosomal rearrangements.