Jumping translocation in a phenotypically normal male: A study of mosaicism in spermatozoa, lymphocytes, and fibroblasts

Abstract

Both Robertsonian translocations, rob(13;13) and rob(13;15), (in the present case defined as dic(13;15)), are rare chromosomal rearrangements and there is scarce information regarding their behavior during meiosis. In this report we describe a man with mosaicism for two cell lines, each cell line containing a different de novo Robertsonian translocation with the common breakpoint in the centromeric region on chromosome 13. The karyotype was finally defined as: 45,XY,rob(13;13)(q10;q10)[29]/45,XY,dic(13;15)(p11.2;p12)[22], a phenomenon referred to as jumping translocation. The relative occurrence of the two clones in lymphocytes and fibroblasts as well as the meiotic segregation in spermatozoa and the mechanism of formation were studied using karyotype analysis, fluorescence in situ hybridization (FISH), and quantitative fluorescence-PCR. Karyotype analysis of cultured lymphocytes revealed 57% rob(13;13) cells and 43% dic(13;15) cells and for cultured skin fibroblasts the figures were almost identical (56% and 44%, respectively). FISH analysis showed 55% balanced nuclei for unselected spermatozoa and after swim-up selection the number of balanced spermatozoa decreased to 41%. In addition, 16% of the unselected spermatozoa and 27% of the spermatozoa after swim-up selection carried an additional chromosome 13, indicating a high risk for a trisomy 13 offspring. Swim-up selection did not increase the number of balanced spermatozoa.

Robertsonian Translocations: An Overview of 872 Robertsonian Translocations Identified in a Diagnostic Laboratory in China

“…Postnatal mosaic ROBs are rare [ 24 , 30 , 31 ]. Nine mosaic ROBs (6 females and 3 males) were identified in the current study, consistent with previous reports that excess mosaic females were obsevered on individuals with autosomal abnormalities [ 24 , 28 , 32 ].…”

The conundrum of a jumping translocation (JT) in CVS from twins and review of JTs

“…The donor site was 18p11.1pter and recipients were 8qter in blood and skin and 20qter in his peripheral blood. The second patient [Iwarsson et al, 2009]; was also infertile with oligoasthenoteratozoospermia. This patient had a normal phenotype with a jumping Robertsonian translocation involving donor 13q10 and recipient 13q10 or 15p12.…”

“…JTs in two infertile males have been reported [Zahed et al, 2004;Iwarsson et al, 2009]. The first patient [Zahed et al, 2004], had hypergonadotropic hypogonadism with azoospermia and a ring chromosome 18q and a JT.…”

Chimerism resulting from parthenogenetic activation and dispermic fertilization

“…Hybridization was performed in a moist chamber at 37°C overnight. FISH was performed as previously described [Iwarsson et al, 2009]. The signals were visualized in metaphase and interphase nuclei using a Zeiss Axioplan 2 fluorescence microscope equipped with cooled CCD camera (Sensys; Photometrics Ltd, Tucson, AZ), controlled by a Power Macintosh computer.…”